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Pagola, S   Benavente, A   Raschi, A   Romano, E   Molina, MAA   Stephens, PW
Crystal structure determination of thymoquinone by high-resolution
   X-ray powder diffraction
The crystal structure of 2-isopropyl-5-methyl-1,4-benzoquinone (
   thymoquinone) and its thermal behavior - as necessary physical and
   chemical properties - were determined in order to enhance the current
   understanding of thymoquinone chemical action by using high resolution
   x-ray powder diffraction, Fourier transform infrared spectroscopy (
   FTIR), and 3 thermo-analytical techniques thermogravimetric analysis
   (TGA), differential thermal analysis (DTA), and differential scanning
   calorimetry (DSC). The findings obtained with high-resolution x-ray
   powder diffraction and molecular location methods based on a simulated
   annealing algorithm after Rietveld refinement showed that the triclinic
   unit cell was a = 6.73728( 8) Angstrom, b = 6.91560( 8) Angstrom, c =
   10.4988( 2) Angstrom, alpha = 88.864( 2)degrees, beta = 82.449( 1)
   degrees, gamma = 77.0299( 9)degrees; cell volume = 472.52( 1)
   Angstrom(3), Z = 2, and space group 1 (1) over bar.


Gomez, A   Rodriguez-Hernandez, J   Reguera, E
Unique coordination in metal nitroprussides: The structure of
   Cu[Fe(CN)(5)NO] .  2H(2)O and Cu[Fe(CN)(5)NO]
The structures of copper pentacyanonitrosylferrate dihydrate,
   Cu[Fe(CN)(5)NO].2H(2)O, and anhydrous, Cu[Fe(CN)(5)NO], have been
   determined from their XRD powder patterns and refined using the
   Rietveld method. The dihydrate structure was solved by direct methods
   and the anhydrous one was elucidated by chemical intuition.
   Cu[Fe(CN)(5)NO].2H(2)O is orthorhombic, space group Amm2 (38) and Z=2.
   In this structure the iron is coordinated to five CN and a NO ligand,
   while the copper atom is coordinated, in a unique fashion, to four
   equatorial CN groups at N ends and two water molecules. Cu[Fe(CN)(5)NO]
   is tetragonal, space group I4 mm (107) and Z=2. This structure is
   obtained from the dehydration of the orthorhombic one; reordering
   allows the Cu atom to coordinate not only to the four equatorial
   cyanides but also to the axial cyanide. The coordination of the iron
   atom remains as in the orthorhombic structure. Agreement factor
   obtained from the final refinement were as follows: R-wp=5.10 and
   R-B=4.57 for the orthorhombic structure and R-wp=6.52 and R-B=7.82 for
   the tetragonal one. These crystal structures are also supported by IR
   and Mossbauer spectroscopic data and thermogravimetry.


Vivani, R   Costantino, F   Nocchetti, M   Gatta, GD
Structural homologies in benzylamino-N,N-bis methylphosphonic acid and
   its layered zirconium derivative
A new layered zirconium diphosphonate fluoride, ZrF(O3PCH2)(2)NHCH2C6H5
   has been prepared and its structure determined ab initio by X-ray
   powder data and refined with the Rietveld method (orthorhombic, a =
   8.9429(2) Angstrom, b = 9.1746(2) Angstrom, c = 31.5654(7) Angstrom,
   space group Pbca, V = 2589.9(1) Angstrom(3), Z = 8, R-wp = 0.080).


Atkinson, TD   Fjellvag, H   Kjekshus, A
Synthesis, structure, and properties of chromium(III) sulfates
Reactions between CrO3 and 50-95 wt% H2SO4 are studied at temperatures
   up to the boiling point of the acid. Depending on the H2SO4
   concentration and synthesis temperature, Cr-2(SO4)(3), CrH(SO4)(2),
   (H3O)[Cr(SO4)(2)], Cr-2(SO4)(3) . H2SO4 . 4H2O (gross formula), and
   (H5O2)[Cr(H2O)(2)(SO4)(2)], are obtained as identified reaction
   products in addition to the incompletely characterized chromic-sulfuric
   acid. The Cr-III-based sulfates are characterized by X-ray powder
   diffraction, thermogravimetric, and magnetic susceptibility
   measurements. The nuclear and magnetic structures of Cr-2(SO4)(3) at 10
   K are determined, the structure type of (H3O)[Cr(SO4)(2)] is
   established, and the crystal structure of (H5O2)[Cr(H2O)(2)(SO4)(2)] is
   firmly stipulated.


Chernyshev, VV   Stephens, PW   Yatsenko, AV   Ryabova, OB   Makarov, VA
Structural characterization of prazosin hydrochloride and prazosin free
three-dimensional solid-state structures of prazosin hydrochloride,
   C19H22N5O4+ . Cl- (A), and prazosin free base, C19H21N5O4 (B), have
   been determined by synchrotron X-ray powder diffraction. A and B
   crystallize in triclinic P-1 and monoclinic Cc space groups,
   respectively, with one structural unit per asymmetric part. In A and B,
   the prazosin molecule adopts different conformations, which do not
   correspond to those obtained by DFT optimizations of protonated and
   free prazosin.


Cremer, U   Disch, S   Ruschewitz, U
CaCu(C2H)(3)  .  6 NH3 and Rb2Cu(C2H)(3)  .  NH3: Two
   ethinylocuprates with a trigonal planar [Cu(C2H)(3)](2-) anion
By reactions in liquid ammonia Ca[Cu(C2H)(3)] (.) 6 NH3 and
   Rb-2[Cu(C2H)(3)](.) NH3 were obtained as polycrystalline solids. The
   new compounds are very sensitive against loss of ammonia and are only
   stable in a NH3 atmosphere at room temperature. Structural
   investigations based on X-ray powder diffraction data resulted in
   hexagonal unit cells (Ca[Cu(C2H)(3)] (.) 6 NH3: P6(3)mc, Z = 2, a =
   986,39(1) pm, c = 926,47(1) pm; Rb-2[Cu(C2H)(3)] (.) NH3: P6(3)/m, Z =
   6, a = 1096,46(2) pm, c = 1600,15(3) pm).


Fantin, G   Fogagnolo, M   Bortolini, O   Masciocchi, N   Galli, S   Sironi, A
Structural and analytical powder diffraction studies of the
   enantioselective inclusion of chiral arylmethylsulfoxides in
   dehydrocholic acid cocrystals
NEW JOURNAL OF CHEMISTRY 28, 2004, 1295-1300.
Dehydrocholic acid (DHA) has been employed in the separation of chiral
   arylmethylsulfoxides through selective precipitation of highly enriched
   1 : 1 cocrystals of p-XC6H4SOMe@DHA (X = Me, OMe, Br, H) formulation.
   X-ray powder diffraction (XRPD) has shown that two, nearly isomorphous,
   but distinct classes of compounds are obtained. Their complete
   structural analysis has been performed by ab initio XRPD methods.


Ivashkevich, LS   Lyakhov, AS   Selevich, AF   Lesnikovich, AI
Crystal structure determination of In-3(H3O)(H2PO4)(6)(HPO4)(2)center
   dot 4H(2)O from X-ray powder diffraction
The crystal structure of indium hydrogen phosphate hydrate,
   In-3(H3O)(H2PO4)(6)(HPO4)(2) . 4 H2O, has been determined from X-ray
   powder diffraction data by using direct methods (EXPO program), and
   refined by FULLPROF package to R-Bragg value of 5.6%. The structure is
   monoclinic, space group C2/c (No. 15), unit cell dimensions a =
   17.0835(5), b = 9.6795(3), c = 17.8776(4) Angstrom, beta =
   90.301(2)degrees, V = 2956.2(1) Angstrom(3), Z = 4, D-x = 2.73 g/cm(3).
   Hydrogen atoms were placed on calculated positions. There are two
   unique indium atoms in the crystal structure. InO6 octahedra are
   connected together via the corners of PO4 tetrahedra to form layers
   parallel to the xy plane. The layers are linked to-ether by water
   molecules, located in the interlayer space, through their hydrogen
   bonds. Within the layers there are hollows occupied by oxonium cations.
   The compound was found to be isostructural with salts of the
   composition M-III M-3(I)(H2PO4)(6)(HPO4)(2) . 4 H2O, where M-III -
   trivalent metal, M-I - monovalent metal, oxonium or ammonium.


Robins, ELR   Brunelli, M   Mora, AJ   Fitch, AN
Low-temperature crystal structure of RS-thiocamphor
DSC and high-resolution powder X-ray diffraction measurements in the
   range 295 K-100 K show that RS-thiocamphor undergoes two phase
   transitions. The first, at around 260 K on cooling, is from the
   room-temperature body-centred-cubic phase to a short-lived
   intermediate. At 258 K the low-temperature form starts to appear. The
   crystal structure of the latter is orthorhombic, space group Pbnm, with
   a = 9.0643(4) Angstrom, b = 14.6714(8) Angstrom, c = 7.2878(4)
   Angstrom, Z = 4, rho(calc) = 1.15 g cm(-3) at 100 K. The structure is
   twofold disordered, with the enantiomers superimposed in the average
   structure, related by the mirror plane.


Mathieu, Y   Paillaud, JL   Caullet, P   Bats, N
Synthesis and characterization of IM-10: a new microporous
   silicogermanate with a novel topology
A novel GeO2 or (Si,Ge)O-2 zeolite phase called IM-10 was obtained in
   the presence of the well-known hexamethonium ion as template and in
   fluoride media, from gels with Ge/Si molar ratios greater than or equal
   to 1. With decrease of the Ge/Si molar ratio, BEC-type zeolite and
   ITH-type zeolite were successively obtained. The recovered IM-10
   samples were characterized by X-ray diffraction, SEM, elemental and
   thermal analysis, F-19 MAS and H-1 liquid (after dissolution of the
   samples in HF) spectroscopies. Due to the small crystal sizes (1-4
   mum), the structure was determined from powder X-ray diffraction (of
   the GeO2 as-made sample) and refined by the Rietveld method. IM-10 is a
   new member of the clathrate family. It crystallizes in the tetragonal
   symmetry, the space group being P (4) over bar n2. The framework is
   made of F--containing D4R units, bridged by GeO4 tetrahedra. The
   arrangement of the D4R units creates [6(20)4(2)] supercages, each of
   them occluding one hexamethonium cation. Structural similarities exist
   between ASU-9 (AST), ASU-7 (ASV) and the new IM-10 zeolite with a novel
   topology (UOZ).


Ma, HW   Liang, JK   Wu, L   Liu, GY   Rao, GH   Chen, XL
Ab initio structure determination of new compound Ba-3(BO3)(PO4)
Ba3BPO7; borophosphate; structure determinations; x-ray powder
The crystal structure of new compound Ba3BPO7 was determined by ab
   initio method from high-resolution conventional X-ray powder
   diffraction data. The Rietveld refinement converged to R-p = 5.92%,
   R-wp = 8.87%, R-exp = 5.00% with the following details: Hexagonal,
   space group P6(3)mc, a = 5.4898 (1) Angstrom, c = 14.7551 (1) Angstrom,
   Z = 2.


Fukuda, K   Moriyama, A   Hashimoto, S
Crystal structure and phase transitions of strontium zirconium
   diorthophosphate, SrZr(PO4)(2)
The crystal structure of SrZr(PO4)(2) at 298 K was determined from
   conventional X-ray powder diffraction data using direct methods, and it
   was further refined by the Rietveld method. The structure was triclinic
   (space group P (1) over bar, Z = 2) with a = 0.77508(4) nm, b =
   0.78887(5) nm, c = 0.51251(3) nm, alpha = 95.754(3)degrees, beta =
   90.228(2)degrees, gamma = 92.474(2)degrees, and V = 0.31149(3) nm(3).
   Final reliability indices were R-wp = 8.51%, R-P = 6.07%, and R-B =
   2.46%. The powder specimens were also examined by high-temperature XRD
   and differential thermal analysis to reveal the occurrence of phase
   transitions from triclinic to monoclinic at 405 K, then to hexagonal
   (or trigonal) at 1196 K during heating. Upon cooling, the reverse
   change of the latter transition occurred at 1175 K. The subsequent
   monoclinic-to-triclinic transition was martensitic and incomplete
   during further cooling to 298 K. The monoclinic phase is most probably
   isostructural with yavapaiite. The present paper has described, for the
   first time, the higher- and lower-temperature polymorphs of the
   yavapaiite-type structure.


Millini, R   Carluccio, LC   Carati, A   Bellussi, G   Perego, C   Cruciani, G   Zanardi, S
ERS-12: A new layered tetramethylammonium silicate composed by
   ferrierite layers
The new layered silicate ERS-12 was synthesized using
   tetraethylorthosilicate (TEOS) as source of silica and
   tetramethylammonium hydroxide (TMA-OH) as a structure directing agent.
   ERS-12 crystallizes also as germanosilicate, but not as alumino- and
   titanosilicate. Structure determination of as-synthesized ERS-12 was
   performed using alpha combined approach of experimental and molecular
   modeling techniques. It is composed by a regular stacking of ferrierite
   layers, with the TMA cations located in the interlayer region. Rietveld
   refinement of the high resolution synchrotron X-ray diffraction (SXPD)
   pattern of as-synthesized ERS-12 structure was firstly carried out in
   the monoclinic P2(1)/m space group; however, to avoid the presence of
   linear Si-O-Si angles, final refinement was. performed in the acentric
   P2(1) space group, which gave unit cell parameters a = 10.5606 (2), b =
   13.9692 (1), c = 7.4148(1) Angstrom, beta = 97.981(2)degrees and
   agreement factors of R-p = 8.9%, R-wp = 12.4% and R-F(2) = 12.2%. Upon
   calcination, a remarkable change of the SXPD pattern occurred with the
   contemporarily presence of sharp and asymmetrically broadened
   reflections, indicative of the formation of a disordered structure;
   this was confirmed by the DIFFaX study carried out in order to evaluate
   the stacking sequences of ferrierite layers. The simulation suggested
   that the layers do not fully condense upon calcinations to form a
   completely connected framework.


Bulychev, BM   Shpanchenko, RV   Antipov, EV   Sheptyakov, DV   Bushmeleva, SN   Balagurov, AM
Synthesis and crystal structure of lithium beryllium deuteride Li2BeD4
INORGANIC CHEMISTRY 43, 2004, 6371-6376.
Single-phase ternary deuteride Li2BeD4 was synthesized by a
   high-pressure high-temperature technique from LiD and BeD2. The crystal
   structure of Li2BeD4 was solved from X-ray and neutron powder
   diffraction data. The compound crystallizes in the monoclinic space
   group P2(1)/c with lattice parameters a = 7.06228(9) Angstrom, b =
   8.3378(1) Angstrom, c = 8.3465(1) Angstrom, beta=93.577(1)degrees, and
   Z = 8. Its structure contains isolated BeD4 tetrahedra and Li atoms
   that are located in the structure interstices. Li2BeD4 does not undergo
   any structural phase transitions at temperatures down to 8 K.


Hull, S    Berastegui, P
Crystal structures and ionic conductivities of ternary derivatives of
   the silver and copper monohalides - II: ordered phases within the
   (AgX)(x)-(MX)(1-x) and (CuX)(x)-(MX)(1-x) (M = K, Rb and Cs; X = Cl, Br
   and I) systems
The crystal structures of 23 ternary phases present in the systems
   (AX)(x)-(MX)(1-x) (A = Ag, Cu; M= K, Rb and Cs; X= Cl, Br and 1) have
   been determined and/or refined using X-ray and neutron diffraction
   studies of powder samples. A total of 11 x = 0.333 phases of
   stoichiometry M(2)AX(3) are found (Rb2AgCl3, Cs2AgCl3, Rb2AgBr3,
   Cs2AgBr3, K2AgI3, Rb2AgI3, Cs2AgI3, K2CuCl3, K2CuBr3, Rb2CuBr3 and
   Rb2CuCl3) which crystallize in one of two closely related crystal
   structures with space group Pnma. The x = 0.4 composition is
   characterized by three compounds Cs3Cu2X5 (X= Cl, Br, 1) which all
   adopt space group Pnma, whilst the x = 0.5 case comprises the two
   compounds CsAgCl2 and CsAgBr2, which possess space group Cmcm. The
   latter undergo phase transitions at 408(5) and 413(8) K, respectively,
   to higher symmetry structures in space group P4/nmm. Five x = 0.667
   compounds of stoichiometry MCu2X3 have been identified (CsCu2Cl3,
   CsCu2Br3, CsCu2I3, RbCu2Br3, and RbCu2I3). Together with CsAg2I3, these
   form a family of compounds, which crystallize in one of two closely
   related structures (space group Pbnm or Cmcm).


Vicente, J   Gil-Rubio, J   Bautista, D   Sironi, A   Masciocchi, N
Synthesis and reactivity of fluoro complexes: Part 2. Rhodium(I) fluoro
   complexes with alkene and phosphine ligands. Synthesis of the first
   isolated rhodium(I) bifluoride complexes. Structure of
   [Rh-3(mu(3)-OH)(2)(COD)(3)](HF2) by X-ray powder diffraction
INORGANIC CHEMISTRY 43, 2004, 5665-5675.
The reaction between [Rh(mu-OH)(COD)](2) (COD = 1,5-cyclooctadiene) and
   73% HF in THF gives [Rh-3(mu(3)-OH)(2)(COD)(3)](HF2) (1). Its crystal
   structure, determined by ab initio X-ray powder diffraction methods
   (from conventional laboratory data), contains complex trimetallic
   cations linked together in 1 D chains by a mu(3)-OH... F-H-F...
   HO-mu(3) sequence of strong hydrogen bonds. The complex
   [Rh(mu-F)(COE)(2)](2) (COE = cyclooctene; 2), prepared by reacting
   [Rh(u-OH)(COE)(2)](2) with NEt3.3HF (3:2), has been characterized.
   Complex 1 reacts with PR3 (1:3) to give [RhF(COD)(PR3)] [R = Ph (3),
   C6H4OMe-4 (4), Pr-i (5), Cy (6)] that can be prepared directly by
   reacting [Rh(U-OH)(COD)](2) with 73% HF and PR3 (1:2:2). The reactions
   of 1 with PPh3 or Et3P have been studied by NMR spectroscopy at
   different molar ratios. Complexes [RhF(PEt3)(3)] (7), [RhF(COD)(PEt3)]
   (8), and [RhF(PPh3)(3)] (9) have been detected. The complex
   [Rh(F)(NBD)(Pr3P)] (NBD = norbornadiene; 10) was prepared by the
   sequential treatment of [Rh(mu-OMe)(NBD)](2) with 1 equiv of NEt3.3HF
   and Pr3P. The first isolated bifluoride rhodium(I) complexes
   [Rh(FHF)(COD)(PR3)] [R = Ph (11), Pr-i (12), Cy (13)], obtained by
   reacting fluoro complexes 3, 5, and 6 with NEt3.3HF (3:1), have been
   characterized. The crystal structures of 3 and 11 have been determined.


Gomez-Alcantara, MM   Cabeza, A   Martinez-Lara, M   Aranda, MAG
   Suau, R   Bhuvanesh, N   Clearfield, A
Synthesis and characterization of a new bisphosphonic acid and several
   metal hybrids derivatives
INORGANIC CHEMISTRY 43, 2004, 5283-5293.
Commercial bis-(4-bromophenyl)-ether, [BrC6H4](2)-O, has been used to
   prepare 4-[4'-(diethoxyphosphoryl)phenoxy]phenyl-phosphonic acid
   diethyl ester, [(CH3CH2)(2)O3P-C6H4](2)-O, (I) following a slight
   modification of the Michaelis-Arbuzov reaction. The acid hydrolysis of
   I gave 4-(4'-phosphonophenoxy)phenyl phosphonic acid, [H2O3P-C6H4](2)-O
   (II), and both compounds have been characterized by H-1 NMR and C-13
   NMR. The crystal structure of II has been determined by single-crystal
   X-ray diffraction. II crystallizes in an orthorhombic unit cell, space
   group Pbcn, with a = 7.822(3) Angstrom, b = 5.821(2) Angstrom, c =
   28.982(9) Angstrom, and V = 1319.7(7) Angstrom(3). The final R factor
   was R1 = 0.0614. The structure is layered, being held together through
   a hydrogen bonding network. II has been used as precursor in the
   syntheses of new metal (Mn, Fe, Co, Ni, Cu, and Zn) bisphosphonates.
   The syntheses were carried out using a fixed metal/bisphosphonic acid
   molar ratio of 2.1:1 and the influence of the pH in the reactions has
   been studied. Nine new compounds have been isolated:
   Mn-2(O3PC6H4OC6H4PO3)(.)1.5H(2)O (III),
   Mn-5(OH)(2)(O3PC6H4OC6H4PO3)(2)(.)2H(2)O (IV),
   Fe(HO3PC6H4OC6H4PO3)(.)0.5H(2)O M, CO2(O3PC6H4OC6H4PO3)(.)2H(2)O (VI),
   Ni-2(O3PC6H4OC6H4PO3)(.)3H(2)O (VII), Ni-2(O3PC6H4OC6H4PO3)(.)2H(2)O
   (VIII), Cu-2(O3PC6H4OC6H4PO3) (IX), Zn-2(O3PC6H4OC6H4PO3) (X), and
   Zn(HO3PC6H4OC6H4PO3H) (XI). Compound IX crystallizes in an orthorhombic
   unit cell, space group Pbcn, and unit cell parameters a = 8.1012(5)
   Angstrom, b = 5.3109(3) Angstrom, c = 29.2595(5) Angstrom, and V =
   1258.8(1) Angstrom(3). Its structure has been solved by ab initio
   powder diffraction and refined by the Rietveld method to R-F = 0.042.
   IX has a pillared layer framework with highly distorted CuO5 groups
   sharing edges to give isolated dimers. XI was indexed in a monoclinic
   unit cell, space group P112(1), with parameters a = 9.4991 (9)
   Angstrom, b = 5.0445(5) Angstrom, c = 29.131(2) Angstrom, gamma =
   91.945(7)degrees, and V = 1395.1(3) Angstrom(3). Its structure has been
   refined by the Rietveld method, R-F = 0.054, since it is isostructural
   with the known compound, Zn[HO3P(C6H4)(2)PO3H]. All solids were also
   characterized by thermal analysis and IR and UV-Vis spectroscopies.


Chernaya, VV   Tsirlin, AA   Shpanchenko, RV   Antipov, EV   Gippius, AA
   Morozova, EN   Dyakov, V   Hadermann, J   Kaul, EE   Geibel, C
Crystal structure and properties of Na2MVO(PO4)(2), the new
   vanadyl(IV)phosphates M=Ca and Sr
Two new complex vanadyl(IV)phosphates Na2MVO(PO4)(2) (M = Ca, Sr) were
   synthesized in evacuated quartz ampoules and investigated by means of
   X-ray diffraction, electron microscopy, DTA, ESR and magnetic
   susceptibility measurements. The crystal structure of Na2SrVO(PO4)(2)
   was solved ab initio from X-ray powder diffraction data. Both compounds
   are isostructural: a = 10.5233(3) Angstrom, b = 6.5578(2) Angstrom, c =
   10.0536(3) Angstrom and a = 10.6476(3) Angstrom, b = 6.6224(2)
   Angstrom, c = 10.2537(3) Angstrom for Ca and Sr, respectively; S.G.
   Pnma, Z = 4. The compounds have a three-dimensional structure
   consisting of V4+ O-6 octahedra connected by PO4 tetrahedra via five of
   the six vertexes forming a framework with cross-like channels. The
   strontium and sodium atoms are located in the channels in an ordered
   manner. Electron diffraction as well as high-resolution electron
   microscopy confirmed the structure solution. The new vanadylphosphates
   are Curie-Weiss paramagnets in a wide temperature range down to 2 K
   with theta = 12 and 5 K for Ca and Sr phases, respectively.


Albov, DV   Davydov, DV   Chernyshev, VV
Di-mu-hydroxo-bis[(N,N,N ',N '-tetramethylethylenediamine)copper(II)]
   dichloride from X-ray powder data
The crystal structure of the title complex,
   [Cu-2(OH)(2)-(TMEDA)(2)]Cl-2 (TMEDA is
   N,N,N',N'-tetramethylethylene-diamine, C6H16N2) has been characterized
   by X-ray powder diffraction. The cation is a binuclear complex with a
   Cu...Cu distance of 3.031 (7) Angstrom and occupies a special position
   of 222 symmetry, while the chloride anions are on a twofold axis. There
   is a hydrogen bond linking a bridging hydroxy group with the anion
   [O...Cl = 2.993 (14) Angstrom].


Filonenko, VP   Sundberg, M   Werner, PE   Zibrov, IP
Structure of a high-pressure phase of vanadium pentoxide beta-V2O5
A high-pressure phase of vanadium pentoxide, denoted beta-V2O5, has
   been prepared at P = 6.0 GPa and T = 1073 K. The crystal structure of
   beta-V2O5 has been studied by X-ray and neutron powder diffraction, and
   high-resolution transmission electron microscopy. The V atoms are
   six-coordinated within distorted VO6 octahedra. The structure is built
   up of quadruple units of edge-sharing VO6 octahedra linked by sharing
   edges along [ 010] and mutually connected by sharing corners along
   [001]. This arrangement forms layers of V4O10 composition in planes
   parallel to ( 100). The layers are mutually held together by weak
   forces. beta-V2O5 is metastable and transforms to alpha-V2O5 at 643 -
   653 K under ambient pressure. Structural relationships between beta-
   and alpha-V2O5, and between beta-V2O5 and B-Ta2O5-type structures are
   discussed. The high-pressure beta-V2O5 layer structure can be
   considered as the parent of a new series of vanadium oxide bronzes with
   cations intercalated between the layers.


Platteau, C   Lefebvre, J   Affouard, F   Derollez, P
Ab initio structure determination of the hygroscopic anhydrous form of
   a-lactose by powder X-ray diffraction
Annealing of alpha-lactose monohydrate at 408 K yielded a mixture of
   this compound with hygroscopic anhydrous alpha-lactose. A powder X-ray
   diffraction pattern of this mixture was recorded at room temperature.
   The starting structural model of hygroscopic alpha-lactose was found by
   a Monte Carlo simulated-annealing method. The final structure was
   obtained through Rietveld refinements, with soft restraints on
   interatomic bond lengths and bond angles, and crystalline energy
   minimization to locate the H atoms of the hydroxy groups. The
   crystalline cohesion is achieved by networks of O - H ... O hydrogen
   bonds that differ from those of the monohydrate phase. The width of the
   Bragg peaks is interpreted by a phenomenological microstructural
   approach in terms of isotropic size effects and anisotropic strain


Rosdahl, J   Persson, I   Lars, K   Stahl, K
On the solvation of the mercury(I) ion. A structural, vibration
   spectroscopic and quantum chemical study
INORGANICA CHIMICA ACTA 357, 2004, 2624-2634.
The structure of solid
   anhydrous mercury(l) trifluoromethanesulfonate, Hg-2(CF3SO3)(2) (1),
   has been determined by powder diffraction methods. The structure
   comprises of discrete molecules, where each mercury binds to an oxygen
   atom in the anion, forming an almost linear O-Hg-Hg-O entity; the
   Hg-Hg-O angle is 173degrees and the Hg-Hg and Hg-O bond lengths are
   2.486(6) and 2.099(22) Angstrom, respectively.


Kyoi, D   Sato, T   Ronnebro, E   Tsuji, Y   Kitamura, N   Ueda, A
   Ito, M   Katsuyama, S   Hara, S   Noreus, D   Sakai, T
A novel magnesium-vanadium hydride synthesized by a
   gigapascal-high-pressure technique
A magnesium-based vanadium-doped hydride was prepared in a
   high-pressure anvil cell by reacting a MgH2-25%V molar mixture at 8 GPa
   and 873 K. The new magnesium-vanadium hydride has a cubic F-centred
   substructure (a = 4.721 (1) Angstrom), with an additional
   superstructure, which could be described by a doubling of the cubic
   cell axis and a magnesium atom framework, including an ordered
   arrangement of both vanadium atoms and vacancies (a = 9.437(3)
   Angstrom, space group Fm (3) over barm (no. 225), Z = 4, V =
   840.55,Angstrom(3)). The metal atom structure is related to the Ca7Ge
   type structure but the refined metal atom composition with vacancies on
   one of the magnesium sites corresponding to Mg6V nearly in line with
   EDX analysis.


Song, GB   Han, CQ   Chen, XL   Liang, JK   Liu, QL   Zhou, YQ   Liu, FS   Rao, GH
Subsolidus phase relations and crystal structure of compounds in the
   PrOx-CaO-CuO system
The subsolidus phase relations of the PrOx-CaO-CuO pseudo-ternary
   system sintered at 950-1000degreesC have been investigated by X-ray
   powder diffraction. In this system, there exist one compound
   Ca10Pr4Cu24O41, one Ca2Pr2Cu5O10-bascd solid solution, seven
   three-phase regions and two two-phase regions. The crystal structures
   of Ca10Pr4Cu24O41, and Ca2Pr2Cu5O10-based solid solution have been
   determined. Compound Ca10Pr4Cu24O41 crystallizes in an orthorhombic
   cell with space group D-2h(20) - Cccm, Z = 4. Its lattice parameters
   are a = 11.278(2) Angstrom, b = 12.448(3) Angstrom and c = 27.486(8)
   Angstrom. The crystal structure of Ca2Pr2Cu5O10-based solid solution is
   an incommensurate phase based on the orthorhombic NaCuO2 type subcell.
   The lattice parameters of the subcell of the Ca2.4Pr1.6Cu5O10 are a(0)
   = 2.8246(7) Angstrom, b(0) = 6.3693(5) Angstrom, c(0) = 10.679(1)
   Angstrom, and those of the orthorhombic superstructure are with a =
   5a(0), b = b(0), c = 5c(0). The Ca2.4Pr1.6Cu5O10 structure can also be
   determined by using a monoclinic supercell with space group C-2h(5) -
   P2(1)/c, Z = 4, a = 5a(0), b = b(0), c = c(0)/sin beta and beta =
   104.79(1)degrees or 136.60(1)degrees, V = 5a(0)b(0)c(0).


Bellitto, C   Bauer, EM   Righini, G   Altomare, A
Synthesis and magnetic properties of a new Cr(II)
   ammonium-ethyl-phosphonate: Cr-1.5[H3N(CH2)(2)PO3](SO4)  .
A new molecule based magnet of formula Cr-1.5[H3N(CH2)(2)PO3](SO4) (.)
   2H(2)O has been prepared and characterized. The magnetization vs. field
   and temperature measurements revealed the compound to be a soft
   weak-ferromagnet at T-N = 4.9 K.


Botez, CE   Stephens, PW   Omotoso, O
Crystal structure of dicalclum chromate hydrate
POWDER DIFFRACTION 19, 2004, 133-136.
Direct methods and Rietveld analysis were applied to high-resolution
   synchrotron X-ray powder diffraction data to solve the crystal
   structure of dicalcium chromate hydrate (Ca2CrO5.3H(2)O). The compound
   crystallizes in monoclinic symmetry (space group Cm, Z=2), with a
   =8.23575(5) Angstrom, b=7.90302(4) Angstrom, c=5.20331(3) Angstrom, and
   beta=98.0137(3)degrees. The structure is built from double-layers of
   CrO4 tetrahedra and CaO8 polyhedra that run parallel to the (001)


Ivashkevich, LS   Lyakhov, AS   Selevich, AF   Lesnikovich, AI
Crystal structure determination of Ga-3(H3O)H-8(PO4)(6) .  6 H2O
   from X-ray powder diffraction data
The crystal structure of the gallium hydrogen phosphate hydrate,
   Ga-3(H3O)H-8(PO4)(6) (.) 6 H2O, has been determined from X-ray powder
   diffraction data. The structure is trigonal, space group P31c (No.
   159), with unit cell dimensions a = 9.0227(1) Angstrom, c = 16.6389(3)
   Angstrom, V = 1173.08(3) Angstrom(3), Z=2, and D-x = 2.59g/cm(3). The
   structure was solved by direct methods using EXPO program and refined
   by FULLPROF package to R-Bragg value of 8.6%. Positions of hydrogen
   atoms were not defined. There are three unique gallium atoms in the
   crystal structure, having octahedral oxygen coordination. GaO6
   octahedra are linked together via the corners Of PO4 tetrahedra to form
   a three-dimensional network with channels running along the c axis.
   There are two types of water molecules in the crystal, which
   essentially differ in their atomic environment. Oxonium cations, lying
   on crystallographic threefold axis, are surrounded by oxygen atoms of
   the phosphate groups and water molecules.


Thoma, SG   Bonhomme, F   Cygan, RT
Synthesis, crystal structure, and molecular modeling of a layered
   manganese(II) phosphate: Mn-3(PO4)(4) .  2(H3NCH2CH2)(3)N center
   dot 6(H2O)
CHEMISTRY OF MATERIALS 16, 2004, 2068-2075.
A novel layered manganese(II) phosphate,
   Mn-3(PO4)(4).2(H3NCH2CH2)(3)N.6(H2O), has been synthesized
   solvothermally using tris(2-aminoethyl)amine (TREN) as a template. The
   structure was solved A initio using X-ray powder diffraction data and
   confirmed by molecular modeling.
   The compound crystallizes in the trigonal space group P $(3)
   over bar $ c1 with a = 8.8706(4) Angstrom, c = 26.158(2) Angstrom, and
   V= 1782.6(2) Angstrom(3). The structure consists of layers of corner
   sharing Mn(II)O-4 and PO4 tetrahedra forming infinite
   [Mn-3(PO4)(4)](6-)macroanions with 4.6 net topology, sandwiched by
   layers of TREN and water molecules. The protonated TREN molecules
   provide charge balancing for the inorganic sheets; the interlayer
   stability is accomplished mainly by a network of hydrogen bonds between
   water molecules and the inorganic macroanions. This hybrid
   organic/inorganic layered material can be reversibly dehydrated.


Rukiah, M   Lefebvre, J   Descamps, M   Hemon, S   Dzyabchenko, A
Ab initio structure determination of m-toluidine by powder X-ray
The powder X-ray diffraction pattern of the crystalline phase of
   m-toluidine has been recorded with a sensitive curved detector (CPS120)
   at 150 K. The structure has been solved by real-space methods (
   simulated annealing) followed by Rietveld refinements with phenyl rings
   as rigid bodies and with soft constraints on bond lengths for
   peripheral atoms. The cell is monoclinic with space group P2(1)/c and Z
   = 8. Equivalent molecules form chains along c. The crystalline cohesion
   is achieved by N-H...N hydrogen bonds between neighbouring chains of
   non-equivalent molecules and by van der Waals interactions of
   neighbouring chains of equivalent molecules. The hydrogen-bonding
   network has been confirmed by lattice-energy minimization. Anisotropic
   strain effects of the cell have been calculated. The directions of the
   minimal strains correspond to the directions of the hydrogen bonds. An
   explanation of the difficulty to crystallize the metastable phase is


Vila, E   Rojo, JM   Iglesias, JE   Castro, A
Polymorphism and electrical properties in the new oxide Bi6Mo2O15
CHEMISTRY OF MATERIALS 16, 2004, 1732-1739.
A new oxide of composition Bi6Mo2O15 has been isolated in the binary
   system Bi2O3- MoO3. A wet-chemistry procedure, different from
   coprecipitation, has been used to prepare a nanosized, very reactive
   precursor. Annealing at different temperatures and for different time
   lengths leads to isolated polycrystalline polymorphs. X-ray powder
   diffraction studies on the hitherto unknown low-temperature form,
   L-Bi6Mo2O15, show that it crystallizes in the monoclinic system, with
   unit-cell parameters a = 29.0674(5) Angstrom, b = 5.64795(7) A, c
   8.6620(1) Angstrom, beta = 97.979(1)degrees, and V = 1408.3
   Angstrom(3). The high-temperature polymorph, H-Bi6Mo2O15, belongs to
   the well-known [Bi12O14] columnar structural type. The relationship
   between the unit-cell parameters of both phases points at the
   connection of their structural frameworks. Impedance spectroscopy
   measurements show that the transition L-H-Bi6Mo2O15 is partially
   reversible, as well as the existence of a second high-temperature phase
   H', similar to H. In contrast, the transition H-->H'-Bi6Mo2O15 is not
   reversible. These materials turn out to be good ionic conductors, with
   conductivities in the order L < H < H' for all temperatures tested.


Pan, ZG   Cheung, EY   Harris, KDM   Constable, EC   Housecroft, CE
Structural aspects of a dendrimer precursor determined directly from
   powder X-ray diffraction data
CRYSTAL GROWTH & DESIGN 4, 2004, 451-455.
The structure of 3,5-dimethoxybenzyl alcohol has been determined
   directly from powder X-ray diffraction data using the genetic algorithm
   technique for structure solution followed by Rietveld refinement. This
   material is the precursor to a family of dendrimer materials, and
   structural features exhibited by 3,5-dimethoxybenzyl alcohol in the
   solid state may be important in the rationalization of higher
   generation dendrimer materials within this family.


Ronnebro, E   Kyoi, D   Blomqvist, H   Noreus, D   Sakai, T
Structural characterization of Mg3CrH similar to 6 - a new
   high-pressure phase synthesized in a multi-anvil cell at 8 GPa
With modem X-ray diffraction refinement methods it was possible to
   identify the first phase in the Mg-Cr-H system, Mg3CrH-6 from minute
   sample volume in spite of poor crystallinity and coexisting impurity
   phases. The new hydride was synthesized at 8 GPa in a high-pressure
   multi-anvil cell at 873 K. An orthorhombic unit cell was found with a =
   9.635(2) Angstrom, b = 8.615(2) Angstrom, c = 4.8040(7) Angstrom, space
   group Pnam (no. 62) Z = 4. V = 398.77 Angstrom(3). Chromium is
   surrounded by a distorted cube of magnesium atoms with average Cr-Mg
   distances of 2.9(1) Angstrom. The hydrogen positions were not possible
   to determine, as only a small sample amount could be prepared. If the
   metal atom structure is compared to already known metal hydrides it can
   be concluded that Mg3CrH-6 consists of chromium hydrido complexes
   counterbalanced by magnesium ions. A high hydrogen content was
   confirmed with thermal desorption spectroscopy.


Loiseau, T   Serre, C   Huguenard, C   Fink, G   Taulelle, F   Henry, M
   Bataille, T   Ferey, G
A rationale for the large breathing of the porous aluminum
   terephthalate (MIL-53) upon hydration
Aluminum 1,4-benzenedicarboxylate
   Al(OH)[O2C-C6H4-CO2](.)[HO2C-C6H4-CO2H](0.70) or MIL-53 as (Al) has
   been hydrothermally synthesized by heating a mixture of aluminum
   nitrate, 1,4-benzenedicarboxylic acid, and water, for three days at
   220degreesC. Its 3D framework is built up of infinite trans chains of
   corner-sharing AlO4(OH)(2) octahedra. The chains are interconnected by
   the 1,4-benzenedicarboxylate groups, creating ID rhombic-shaped
   tunnels. Disordered 1,4-benzenedicarboxylic acid molecules are trapped
   inside these tunnels. Their evacuation upon heating, between 275 and
   420degreesC. leads to a nanoporous open-framework (MIL-53ht (Al) or
   Al(OH)[O2C-C6H4-CO2]) with empty pores of diameter 8.5 Angstrom. This
   solid exhibits a Langmuir surface area of 1590(1) m(2)g(-1) together
   with a remarkable thermal stability, since it starts to decompose only
   at 500degreesC. At room temperature, the solid reversibly absorbs water
   in its tunnels, causing a very large breathing effect and shrinkage of
   the pores. Analysis of the hydration process by solid-state NMR (H-1,
   C-13, Al-27) has clearly indicated that the trapped water molecules
   interact with the carboxylate groups through hydrogen bonds, but do not
   affect the hydroxyl species bridging the aluminum atoms. ne hydrogen
   bonds between water and the oxygen atoms of the framework are
   responsible for the contraction of the rhombic channels. The structures
   of the three forms have been determined by means of powder X-ray
   diffraction analysis. Crystal data for MIL-53 as (Al) are as follows:
   orthorhombic system, Pnma (no. 62), a 17.129(2), b = 6.628(1), c =
   12.182(1) A; for MIL-53ht (Al), orthorhombic system, Imma (no. 74), a =
   6.608(1), b = 16.675(3), c = 12.813(2) Angstrom; for MIL-53 lt (Al),
   monoclinic system, Cc (no. 9), a = 19.513(2), b = 7.612(1), c =
   6.576(1) Angstrom, beta = 104.24(1)degrees.


Ferreira, A   Lin, Z   Soares, MR   Rocha, J
Synthesis and ab initio structure determination from powder diffraction
   data of K4Sn2Si6O18
The crystal structure of a new potassium stannosilicate K4Sn2Si6O18
   (AV-11) has been determined ab initio from powder X-ray diffraction
   data. The unit cell is trigonal, space group R3 (no. 146), Z=3 with
   cell dimensions a = 10.1587, c = 14.8039 Angstrom, gamma= 120degrees, V
   = 1323 Angstrom(3). The structure is made up of SnO6 octahedra and SiO4
   tetrahedra by sharing comers. The SiO4 tetrahedra form a helix chain,
   periodically repeating every six tetrahedra. These chains extend along
   the [001] direction and are linked by isolated Sn-O octahedron giving a
   mixed framework.


Scordari, F   Ventruti, G   Gualtieri, AF
The structure of metahohmannite, Fe-2(3+)[O(SO4)(2)] .  4H(2)O,
   by in situ synchrotron powder diffraction
AMERICAN MINERALOGIST 89, 2004, 365-370.
Metahohmannite, Fe-2(3+)[O(SO4)(2)].4H(2)O, is a hydrated sulfate of
   ferric iron that occurs in sulfate deposits in the desert areas of
   Northern Chile. The compound used for this study was obtained as a
   dehydration product of hohmannite, Fe-2(3+)[O(SO4)(2)].(4+4)H2O.
   Intensities for the structure analysis were collected from a powdered
   sample using in situ synchrotron X-ray powder diffraction at ESRF
   (Grenoble, France). The structure was solved ab initio by profile
   deconvolution and the application of standard Patterson and difference
   Fourier maps. The structure was refined to R-p = 5.46% using the
   Rietveld method. Metahohmannite crystallizes in the triclinic system,
   space group P (1) over bar with unit-cell parameters a = 7.3484(5)
   Angstrom, b = 9.7710(6) Angstrom, c = 7.1521(5) Angstrom, alpha =
   91.684(5)degrees, beta = 98.523 (5), gamma = 86.390(5)degrees, and Z =
   2. The structure consists of four Fe3+ octahedra and four sulfate
   tetrahedra, which share vertices and edges to form a complex building
   block of Fe-4(3+)[O-2(SO4)(4)].8H(2)O composition. Such blocks are
   connected to form chains running parallel to the c axis. A complicated
   system of hydrogen bonds connects adjacent chains into a
   three-dimensional network. Finally, the crystal structures of
   metahohmannite, hohmannite, and amarantite are compared and the
   geometrical features discussed in detail.


Muhle, C   Dinnebier, RE   van Wullen, L   Schwering, G   Jansen, M
New insights into the structural and dynamical features of lithium
   hexaoxometalates Li7MO6 (M= Nb, Ta, Sb, Bi)
INORGANIC CHEMISTRY 43, 2004, 874-881.
We present a (re)investigation of the hexaoxometalates Li8MO6 (M = Sn,
   Pb, Zr, Hf) and Li7MO6 (M = Nb, Ta, Sb, Bi). Lithium motion and ionic
   conductivity in the hexaoxometalates were studied using impedance
   spectroscopy (for Li7MO6, M = Sb, Bi, Ta) and Li-6 and Li-7 solid-state
   nuclear magnetic resonance (for Li7TaO6). The NMR data indicate a
   considerable exchange of Li among the tetrahedral and octahedral voids
   even at ambient temperature. In an investigation of the crystal
   structures using laboratory and synchrotron X-ray powder diffraction
   techniques, the structures of Li7TaO6, Li7NbO6, and Li7SbO6 could be
   solved and refined. All three reveal a triclinic metric (Li7SbO6,
   triclinic, P (1) over bar, a = 5.38503(6) Angstrom, b = 5.89164(7)
   Angstrom, c = 5.43074(6) Angstrom, alpha = 117.2210(6)degrees, beta =
   119.6311(6)0, gamma = 63.2520(7)degrees, V = 127.454(3) Angstrom(3), Z
   = 1; Li7NbO6, triclinic, P (1) over bar, a = 5.37932(9) Angstrom, b =
   5.91942(11) Angstrom, c = 5.37922(9) Angstrom, alpha = 117.0033(9)-,
   beta = 119.6023(7)degrees, gamma = 63.2570(9)degrees, V = 126.938(4)
   Angstrom(3), Z = 1; Li7TaO6, triclinic, P (1) over bar, a = 5.38486(2)
   Angstrom, b = 5.92014(3) Angstrom, c = 5.38551(2) Angstrom, alpha =
   117.0108(2)degrees, beta = 119.6132(2)degrees, gamma =
   63,2492(2)degrees, V = 127.208(1) Angstrom(3), Z = 1.


Bakhmutova-Albert, EV   Bestaoui, N   Bakhmutov, VI   Clearfield, A   Rodriguez, AV   Llavona, R
A novel cadmium aminophosphonate: X-ray powder diffraction structure,
   solid-state IR and NMR spectroscopic determination of the fine
   structure of the organic moieties
INORGANIC CHEMISTRY 43, 2004, 1264-1272.
A new divalent cadmium phosphonate, Cd2Cl2(H2O)(4)(H2L), has been
   synthesized from the ethylenediamine-N,N'-bis(methylenephosphonic acid)
   (H4L). The obtained microcrystalline compound has been characterized by
   solid-state IR spectra and C-13, P-31, and Cd-113 CP MAS NMR. The
   static P-13 NMR spectra have been also recorded to give the delta(11),
   delta(22), and delta(33) chemical shift parameters for both compounds.
   The spectral data, collected for Cd2Cl2-(H2O)(4)(H2L), are in an
   agreement with its X-ray powder diffraction structure solved with the
   cell dimensions a = 16.6105(10), b = 7.1572(4), and c = 6.8171(4)
   Angstrom and beta = 98.327(4)degrees. The octahedral coordination
   sphere of the cadmium atoms consists of two phosphonate oxygen atoms,
   two water oxygen atoms, and the two chlorine atoms. Cadmium atoms are
   bridged by the chlorine atoms forming four-membered rings. The
   phosphorus atoms exhibit a tetrahedral coordination with two oxygen
   atoms bonded to the cadmium atoms with P-O distances of 1.503(10) and
   1.504(10) Angstrom. The third oxygen atom, showing a longer P-O
   distance (1.546(9) Angstrom), is not bonded to the metal center, nor is
   it bonded to a proton. The combined IR and NMR proton-phosphorus
   cross-polarization kinetic data together with the X-ray data confirm
   that the cadmium phosphonate has the zwitterionic structure
   (NH2+CH2P(O2Cd2)O-) similar to the initial aminophosphonic acid H4L.


Barea, E   Navarro, JAR   Salas, JM   Masclocchi, N   Galli, S   Sironi, A
Coordination frameworks containing the pyrimidin-4-olate ligand.
   Synthesis, thermal, magnetic, and ab initio XRPD structural
   characterization of nickel and zinc derivatives
INORGANIC CHEMISTRY 43, 2004, 473-481.
Extended coordination frameworks containing the pyrimidin-4-olate
   ligand (4-pymo) and Zn(II) and Ni(II) metal ions have been obtained by
   solid state reactions and have been fully characterized by
   spectroscopic, thermal, and magnetic measurements and by ab initio
   XRPD. The reaction of ZnO and 4-Hpymo at 140 degreesC gives a solid
   microcrystalline phase, Zn(4-PYMO)(2) (1). Its 3D framework contains
   Zn(II) centers linked by 4-pymo ligands acting in two different
   coordination modes, namely, the N,N'- and the N,O-exo-bidentate ones,
   which result in a pseuclotetrahedral ZnN3O chromophore. Thermal
   treatment of the "molecular' Ni(4-pymo)(2)(H2O)(4) complex (2) above
   140 degreesC gives an anhydrous amorphous material analyzing as
   Ni(4-PYMO)(2) (3a). Further heating of this material above 388 degreesC
   results in the formation of the microcrystalline layered Ni(4-PYMO)(2)
   species (3b), in which Ni(II) centers are bridged by N,O-exo-bidentate
   4-pymo ligands (assisted by longer Ni...N contacts). The thermal
   dependence of the magnetic susceptibility has been studied for the
   paramagnetic species 2 and 3a. 2 shows a weak antiferromagnetic
   interaction [J = -0.313(5) cm(-1)] transmitted through the multiple
   H-bonding interactions between the exocyclic pyrimidine and water
   oxygen atoms coordinated to the metal centers. 3a behaves as a 2D
   Heisenberg antiferromagnet with J = -4.11(3) cm(-1).


Vanhoyland, G   Le Bail, A   Mullens, J   Van Poucke, LC
Characterization and structure determination of ammonium bismuth
   oxalate hydrate, Bi(NH4)(C2O4)(2) . xH(2)O
INORGANIC CHEMISTRY 43, 2004, 785-789.
From on-line coupled TGA-MS and TGA-FTIR measurements, in combination
   with a quantitative chemical analysis, it was deduced that the chemical
   formula for an unknown bismuth oxalate compound had to be
   Bi(NH4)(C2O4)(2).3.71(6)H2O. Solution of the crystallographic structure
   on the basis of X-ray powder data proved this formula to be correct.
   The diffraction pattern was indexed by a tetragonal unit cell [a and c
   respectively 11.6896(2) and 9.2357(3) Angstrom; M-20 = 195 and F-30 =
   302; Z(calc) = 4], from which the space group /4(1)/amd (No. 141) was
   derived. Direct methods were applied to solve the structure. The
   initial structural model was subsequently refined by means of the
   Rietveld method (R-B = 8.0%, R-wP = 14.0%). Bi is 8-fold coordinated by
   oxygen from the oxalate anions. Since these BiO8 polyhedrons do not
   share any edges or vertexes, an open framework is formed with water and
   ammonium molecules between. As a result, water can easily be removed,
   which is clearly indicated by the instant weight loss in the TGA upon
   heating. Moreover, as shown by HT-XRD, this process of water exchange
   is reversible as long as the heating temperature does not exceed 100


Serda, P   Grochowski, J   Duddeck, H
The structure of marmesinin by powder and single-crystal diffraction
The crystal and molecular structure of marmesinin C20H24O9, a
   furocoumarine beta-D-glucoside, an important biocontrolling compound
   isolated from the fruits of Ammi majus L. was determined from
   high-resolution powder diffraction using simulated annealing and,
   independently, from microcrystal diffraction. Both structural models
   were in good agreement. High-resolution powder diffraction patterns
   recorded with synchrotron radiation proved to be an efficient method
   for crystal structure determination of poorly-crystallizing natural
   products. (C) 2003 Elsevier B.V. All rights reserved.


Neels, A   Wang, Y   Stoeckli-Evans, H
TStudying the structure of metal-organic polymers using in-house powder
   X-ray diffraction data: structural transformations induced by thermal
The use of X-ray powder diffraction for the structure determination of
   inorganic, organic and metal-organic compounds has grown impressively
   over the last ten years. In supramolecular chemistry, the knowledge of
   the three-dimensional structure of a material is essential for the
   discussion of its macroscopic behaviour, and as a result the design of
   new functionalized materials.
   The ab initio crystal structure determination of previously unknown
   metal-organic compounds is still rare but is a field of high interest
   and activity. Here we describe the formation of ID coordination
   polymers and the phase transformation processes that lead to the
   formation of 3D polymers on heating, accompanied by colour changes.
   The reaction of pyrazine-2,5-dimethyl-3,6-dicarboxylic acid with first
   row transition metal salts lead to the formation of coordination
   polymers always in the form of microcrystalline powders. With manganese
   and nickel salts isostructural 1D coordination polymers were obtained.
   With zinc chloride and copper chloride isomorphous ID coordination
   polymers were obtained. The thermal decomposition of the nickel and
   copper polymers were studied and it was shown that on the loss of the
   coordinated water molecules new 3D coordination polymers could be
   obtained. In both the ID and 3D coordination polymers the metal atoms
   have octahedral geometry in N2O4 environments. The crystal structures
   of all six complexes have been determined from powder X-ray diffraction
   data. Crystal data: (1) crystal symmetry monoclinic [space group
   P2(1)/c, a = 7.4645(1), b = 8.9472(2), c = 7.6166(1) Angstrom, beta =
   92.198(2)degrees]; (2) crystal symmetry orthorhombic [space group Pbcn,
   a = 7.4060(2), b = 7.1857(2), c = 9.0661(2) Angstrom]; (3) crystal
   symmetry monoclinic [space group P2(1)/c, a = 6.9376(9), b =
   7.1306(12), c 8.5852(20) Angstrom, beta = 113.299(18)degrees]; (4)
   crystal symmetry orthorhombic [space group Pbcn, a = 9.0593(2), b
   7.4410(1), c = 14.6697(2) Angstrom]; (5) crystal symmetry orthorhombic
   [space group Pbcn, a = 8.9727(1), b = 7.2354(1), c = 15.0444(2)
   Angstrom]; (6) crystal symmetry monoclinic [space group P2(1)/c, a =
   6.9133(4), b = 7.9927(6), c = 8.2084(6)Angstrom, beta =


Cordier, S   Roisnel, T   Poulain, M
TSynthesis and characterization of the novel Nb3O5F5 niobium
   oxyfluoride: the term n=3 of the NbnO(2n-1)F(n+2) series
The solid-state synthesis of the oxyfluoride Nb3O5F5, its crystal
   structure determined from X-ray powder diffraction data as well as some
   physical characterizations, are reported. Nb3O5F5 constitutes the term
   n = 3 of the NbnO2n-1Fn+2 series related to the Dion-Jacobson phases.
   It crystallizes, at room temperature, in the tetragonal system (space
   group I4/mmm (no. 139); Z = 4; a = 3.9135(1) Angstrom, c = 24.2111(2)
   Angstrom, and V = 370.80(Angstrom(3)) The crystal structure appears to
   be an in-between of the three-dimensional network of NbO2F and the
   two-dimensional packing of NbOF3 (term n = 1 of the NbnO2n-1Fn+2
   series). This layered structure consists of slabs made of three
   Nb(O2F)(6) corner-linked octahedra in thickness (n = 3) shifted one
   from another by a (1/2a + 1/2b)/transiation. Oxygen and fluorine atoms
   are randomly distributed over all the ligand sites.


Rukiah, M   Lefebvre, J   Hernandez, O   van Beek, W   Serpellon, M
Ab initio structure determination of the Gamma form of D-sorbitol
   (D-glucitol) by powder synchrotron X-ray diffraction
A high-resolution powder synchrotron X-ray diffraction pattern of the.
   form of D-sorbitol has been recorded at 293 K on the BM1B beamline at
   the ESRF ( Grenoble). The starting model of the structure was found by
   Monte Carlo simulated annealing. The final structure was obtained
   through Rietveld refinements performed with soft restraints on
   interatomic bond lengths and angles. The symmetry is orthorhombic,
   space group P2(1)2(1)2, with 12 molecules within the cell [a = 24.3012
   ( 2), b = 20.5726 ( 2), c = 4.8672 ( 1) Angstrom, V = 2433.30 ( 3)
   Angstrom(3), Z' = 3, 36 non-H independent atoms]. Crystalline cohesion
   between neighbouring molecules is achieved by three networks of O-H...O
   hydrogen bonds. The width of the Bragg peaks is interpreted through a
   microstructural approach in terms of anisotropic strain effects.


Yang, QB   Wang, PL   Li, YX   Yin, QR   Werner, PE   Moliterni, AGG   Cheng, YB
On the superstructure of KTiO2(OH)
The superstructure of potassium titanate, KTiO2(OH), prepared by
   hydrothermal synthesis has been determined from synchrotron powder
   diffraction data. It is shown that the unit cell of the superstructure
   is rhombohedral: a = 11.13848 Angstrom, alpha = 52.7336degrees. The
   structure has been determined and refined in space group R (3) over
   barc to R-F = 0.074. The distribution of hydrogen atoms as hydroxy
   groups can be explained from the crystal structure described by the


Mahe, N    Bataille, T
Synthesis, crystal structure from single-crystal and powder x-ray
   diffraction data, and thermal behavior of mixed potassium lanthanide
   squarates: Thermal transformations of layered
   [Ln(H2O)(6)]K(H2C4O4)(C4O4)(2) into pillared LnK(C4O4)2 (Ln = Y, La,
   Gd, Er)
INORGANIC CHEMISTRY 43, 2004, 8379-8386.
A new series of mixed potassium and rare-earth squarates,
   [Ln(H2O)(6)]K(H2C4O4)(C4O4)(2) (Ln = Y, La, Gd, Er), has been
   synthesized and structurally characterized from single-crystal X-ray
   diffraction and spectroscopic analyses. The yttrium-based compound
   crystallizes with a monoclinic symmetry, space group C2/c [a =
   8.3341(2) Angstrom, b = 37.7094(g) Angstrom, c = 11.7195(3) Angstrom,
   beta = 90.3959(9)degrees, V = 3683.1(2) Angstrom(3), Z = 8]. The
   structure is built from layers maintained together via hydrogen bonds.
   Within a layer, squarate ligands act as linkers between lanthanide and
   potassium cations. The thermal decomposition of the precursors has been
   studied by powder thermodiffractometry and thermal analyses. It is
   shown that crystalline intermediate phases are formed during the
   degradation. Among them, unprecedented mixed anhydrous squarates,
   LnK(C4O4)(2), could be isolated. The crystal structure of the Y
   compound has been solved ab initio from X-ray powder diffraction data,
   using direct-space methods [a = 6.2010(5) Angstrom, c = 11.639(l)
   Angstrom, V = 447.55 Angstrom(3), Z = 2]. The structure consists of
   layers of edge-sharing YO8 and KO8 antiprisms, pillared by
   mu(8)-squarate groups. The end of the precursor decomposition is marked
   by the formation of cubic sesquioxides Ln(2)O(3), including lanthanum


Zhang, Y   Li, YD
Red photoluminescence and crystal structure of Sr3Y2(BO3)(4)
The crystal structure of a new compound Sr(3)y(2)(BO3)(4) has been
   determined from powder X-ray diffraction data by means of the Rietveld
   method. The structure can be described as being made up of isolated
   triangles, strontium-oxygen polyhedra, and yttrium-oxygen polyhedra.
   The yttrium atom has eight-fold coordination. The strontium atoms have
   10-, 9- and 8-fold coordination in a covalent matrix.
   Sr(3)y(2)(BO3)(4):Eu phosphor exhibits a strong red emission around 615
   nm because Eu3+ ion locates at a non-centrosymmetric site in the host
   lattice. In particular, the compound Sr-3(Y0.9Eu0.1)(2)(BO3)(4) has the
   strongest emission intensity.


Li, YQ   de With, G   Hintzen, H
Synthesis, structure, and luminescence properties of Eu2+ and Ce3+
   activated BaYSi4N7
BaYSi4N7 and its phosphors activated with Eu2+ and Ce3+ were
   synthesized by solid-state reaction at 1400-1650 degreesC under
   nitrogen mixed with hydrogen atmosphere. The crystal structure of
   BaYSi4N7 was solved by direct methods and refined by the Rietveld
   method from powder X-ray diffraction data. BaYSi4N7 crystallizes in the
   hexagonal space group P6(3)mc (No.186), with a = 6.0550 (2) Angstrom, c
   = 9.8567 (1) Angstrom, V = 312.96 (2) Angstrom(3). and Z = 2. which is
   isotypic with BaYbSi4N7. The photoluminescence properties have been
   studied for the solid solutions of Ba1-xEuxYSi4N7 (x = 0-0.4) and
   BaY1-xCexSi4N7 (x = 0-0.1) at room temperature. Eu2+-doped BaYSi4N7
   gives a broad green emission band centered between 503 and 527 nm
   depending on the Eu2+ concentration. The Eu2+ emission band shows a
   red-shift formulation with increasing Eu2+ concentration mainly caused
   by the change of the crystal field strength and Stokes shift.
   Concentration quenching of Eu2+ emission is observed for x = 0.05 due
   to energy transfer between Eu2+ ions by electric dipole-dipole
   interactions with a critical interaction distance of about 20 Angstrom.
   Ce3+-doped BaYSi4N7 exhibits a bright blue emission band with a maximum
   at about 417 nm, which is independent of Ce3+ concentration. This is
   ascribed to a lower solubility of Ce3+ ions in BaYSi4N7 lattice as
   shown by X-ray powder diffraction analysis.
DICVOL, direct methods


Matsuda, R   Kitaura, R   Kitagawa, S   Kubota, Y   Kobayashi, TC
   Horike, S   Takata, M
Guest shape-responsive fitting of porous coordination polymer with
   shrinkable framework
In situ synchrotron X-ray powder diffraction patterns of porous
   coordination polymers {[Cu-2-(pzdc)(2)(bpy)](.)G} have been measured
   (pzdc = pyrazine-2,3-dicarboxylate, bpy = 4,4'-bipyridine) (where G =
   H2O for CPL-2 superset of H2O, G = benzene for CPL-2 superset of
   benzene, and G = void for the apohost). The structures of apohost and
   CPL-2 superset of benzene were determined from Rietveld analysis.
   Adsorption of benzene in the channels induced a remarkable contraction
   in the crystal (b axis; 6.8%, volume; 4.9%), although the channels were
   occupied by the benzene molecules. This crystal transformation provides
   a new pore structure that is well suited for benzene molecules, and we
   denote it as a "shape-responsive fitting" transformation. This type of
   pore gives rise to a new guideline: frameworks can be composed of
   flexible motifs that are linked via strong bond and/or stiff motifs
   that are connected via weaker bonds.


Salamakha, PS   Sologub, OL   Rizzoli, C   Hester, JR   Stepien-Damm, J
   Goncalves, AP   Lopes, EB   Almeida, M
Ternary RPt4B (R = La, Ce, Pr, Nd) compounds; structural and physical
INTERMETALLICS 12, 2004, 1325-1334.
The compounds RPt4B, with (R = La, Ce, Pr, Nd), were synthesized and
   their crystal structure was studied either by single crystal X-ray
   diffraction and/or by conventional and synchrotron X-ray powder
   diffraction. All four compounds of this family are isostructural and
   belong to the CeCo4B structure type. AC-susceptibility and
   magnetization studies show that: there is no magnetic ordering of the
   La compound down to 1.7 K; the Ce compound presents an
   antiferromagnetic-type-transition at 2.4 K; and both Pr and Nd
   compounds present a ferromagnetic-type transition at 4.2 and 4.9 K,
   respectively. Electrical resistivity studies show metallic behaviour
   for all compounds, the temperature dependence for the La compound being
   described by the Bloch Gruneisen relation. Thermopower studies as a
   function of temperature show that the thermopower is positive and small
   for these compounds, which is consistent with hole dominated metallic

2004-49  ????????

Kitaura, R   Iwahori, F   Matsuda, R   Kitagawa, S   Kubota, Y
   Takata, M   Kobayashi, TC
Rational design and crystal structure determination of a 3-D
   metal-organic jungle-gym-like open framework
INORGANIC CHEMISTRY 43, 2004, 6522-6524.
A new three-dimensional (3-D) jungle-gym-like open metal-organic
   framework has been synthesized from a two-dimensional (2-D) layer
   compound using a heterogeneous pillar insertion reaction. Both the
   starting 2-D layer and the resulting 3-D open compounds have been
   characterized using X-ray crystallography.


Johnston, A   Florence, AJ   Shankland, K   Markvardsen, A
   Shankland, N   Steele, G   Cosgrove, SD
Powder study of
   aphthalen-1-ylethoxy)ethylsulfonyl]propylaminium benzoate
The crystal structure of the title compound, C26H31N2O5S2+.-C7O2H5-,
   also known as AR-C69457CC, was solved by simulated annealing from
   laboratory X-ray powder diffraction data collected at room temperature
   to 2.1 Angstrom resolution. Subsequent Rietveld refinement yielded an
   R-wp of 0.038 and site-occupancy factors for the disordered anion
   components of 0.5.
DICVOL, Simulated annealing


Grzechnik, A   Dmitriev, V   Weber, HP   Gesland, JY   van Smaalen, S
LiSrAlF6 with the LiBaCrF6-type structure
The crystal structure of LiSrAlF6-III (P2(1)/c, Z = 4) occurring above
   3.0 GPa at room temperature was studied with synchrotron
   angle-dispersive x-ray powder diffraction in a diamond anvil cell. It
   was solved by combining a global optimization and a topological
   analysis with the Rietveld method using rigid-body AlF6 geometrical
   constraints. LiSrAlF6-III, related to LiBaCrF6 (P2(1)/c, Z = 4), is
   built of deformed SrF12 icosahedra within a three-dimensional framework
   of corner-sharing distorted AlF6 octahedra and LiF4 tetrahedra, whereas
   the low-pressure phases I (P (3) over bar 1c, Z = 2) and II (P2(1)/c, Z
   = 4) have cations exclusively in distorted octahedral coordinations.
   The pressure-induced changes of the coordination polyhedra in the
   series LiSrAlF6-I, LiSrAlF6-II to LiSrAlF6-III are similar to the
   differences in coordination polyhedra due to the increase of the ionic
   radii of the Sr2+ and Ba2+ cations in LiSrAlF6-I and LiBaM"F-6 (M" =
   At, Ga, Cr, V, Fe, or Ti) at ambient conditions. These observations are
   discussed on the basis of the high-pressure high-temperature
   systematics in AB(2)X(6) compounds.


Serre, C   Millange, F   Surble, S   Greneche, JM   Ferey, G
Synthesis, characterization, and properties of an open-framework
   iron(III) dicarboxylate: MIL-85 or
   (Fe2O)-O-III{O2C-CH3}(2){O2C-C6H4-CO2} .  2CH(3)OH
CHEMISTRY OF MATERIALS 16, 2004, 2706-2711.
A new three-dimensional iron(III) dicarboxylate, MIL-85 or
   (Fe2O)-O-III{O2C-CH3}2{O2C- C6H4-CO2}.2CH(3)OH, has been obtained under
   solvothermal conditions, and its structure was determined using X-ray
   powder diffraction data. Its chiral framework is built up from helical
   chains of iron(III) octahedra linked through terephthalate dianions.
   This creates a three-dimensional structure with an array of 1-D
   small-pore channels filled with free and bound methanol moieties. The
   thermal behavior has been investigated using TGA, and X-ray
   thermodiffractometry indicates that MIL-85 is stable up to 275 degreesC
   with a fully reversible departure of solvent process. When the free and
   bound solvent molecules are removed, a nanoporous solid with a Langmuir
   surface area of 110 m(2)/g is obtained. Mossbauer spectrometry confirms
   the presence of high-spin-state Fe3+ within the structure and a change
   in the iron environment upon solvent departure. Finally, one can
   conclude from magnetic data that MIL-85 exhibits a frustrated magnetic
   behavior in the low-temperature range. Crystal data for MIL-85:
   hexagonal space group P6(1) (no. 169) with alpha = 11.045 (1) Angstrom,
   c = 18.823 (1) Angstrom, and Z = 6.


Kaduk, JA
Crystal structure of guaifenesin, 3-(2-methoxyphenoxy)-1,2-propanediol
POWDER DIFFRACTION 19, 2004, 127-132.
The crystal structure of the common expectorant guaifenesin,
   3-(2-methoxyphenoxy)-1, 2-propanediol (C10H14O4) was solved by applying
   Monte Carlo simulated annealing techniques to synchrotron powder data,
   and refined using the Rietveld method. Initial structure solutions
   yielded an unreasonable conformation, and an unacceptable refinement.
   Quantum chemical geometry optimizations were used to identify the
   correct conformation. Guaifenesin crystallizes in the orthorhombic
   space group P2(1)2(1)2(1) (#19), with a=7.65705(7), b=25.67020(24),
   c=4.97966(4) Angstrom, V=978.79(2) Angstrom(3), and Z=4. Both hydroxyl
   groups act as hydrogen bond donors and acceptors, resulting in the
   formation of a two-dimensional network of strong hydrogen bonds in the
   ac plane. The solid state conformation is similar to4 kcal/mol higher
   in energy than the minimum-energy conformation of an isolated molecule,
   but the formation of the hydrogen bonds results in an energy gain of
   similar to100 kcal/mol. Knowledge of the crystal structure permits
   quantitative phase analysis of guaifenesin-containing pharmaceuticals
   (such as Duratuss GP 120-1200) by the Rietveld method.


Audebrand, N   Jeanneau, E   Bataille, T   Raite, S   Louer, D
A family of microporous mixed oxalates with isotypic-framework
   structures based on eight-coordinate metals
SOLID STATE SCIENCES 6, 2004, 579-591.
Structural relationships between mixed oxalates with crystal structures
   consisting of isotypic anionic frameworks [MM'(C2O4)(4)](2-) built from
   dodecahedrally coordinated M and M' metals, with counter cations
   located in tunnels, are described. The principles of a predictive
   structural derivation, based on the YK(C2O4)(2)(.)4H(2)O structure
   type, is presented. Four new phases with isotypic frameworks that
   conform to the classification and to a proposed empirical
   six-valence-sum rule are reported. The new oxalates have been
   synthesised from mild chemistry and their crystal structures have been
   determined from single-crystal or powder diffraction data. Crystal data
   for the new phases are: CdZrSr(C2O4)(4)(.)6H(2)O, S.G. I (4) over bar
   m2, a = 11.2362(4) Angstrom, c = 8.6084(3) Angstrom, Z = 2;
   InK(C2O4)(2)(.)4H(2)O, S.G. I4(1)/a, a = 11.0549(3) Angstrom, c =
   8.9735(3) Angstrom, Z = 4; YRb(C2O4)(2)(.)4H(2)O, S.G. I4(1)/a, a =
   11.4569(3) Angstrom, c = 9.1502(4) Angstrom, Z = 4;
   Ca2Zr(C2O4)(4)(.)5.5H(2)O, S.G. I (4) over bar m2, a = 11.2558(2)
   Angstrom, c = 8.4288(2) Angstrom, Z = 2. The open-framework structures
   of all phases can be described on the basis of building walls made of
   mixed dodecahedra MO8 and M'O-8, connected through bichelating oxalate
   groups. The third element is located in channels with an elliptic
   cross-section. The thermal behaviour of all phases is studied from
   thermogravimetry and thermodiffractometry. It is shown that the
   dehydration process is somewhat related to the structure features and
   depends on the valence of the counter cation. In all cases,
   zeolite-type properties involving weakly bonded water molecules are
   pointed out.


Mora, AJ   Delgado, GE   Pineda, C   Tinoco, T
Synthesis and structural study of the AgIn5Te8 compound by X-ray powder
The AgIn5Te8 compound was synthesized by the melt and annealing
   technique and its structure was refined from X-ray powder diffraction
   pattern using the Rietveld method. AgIn5Te8 crystallizes in the
   tetragonal space group R (4) over bar 2m (N-o 111), Z = 1, with a =
   6.1952(2) Angstrom, c = 12.419(4) Angstrom, V = 476.7(2) Angstrom(3).
   The refinement of 23 instrumental and structural parameters led to R-p
   = 8.2%, R-wp = 11.6%, R-exp = 6.8% and S = 1.7; R-B = 11.2% for 5501
   step intensities and 253 independent reflections. The structure is
   characterized by a double alternation of selenide-metal planes
   according to the In-2-Te-1-In-1-Te-2-Ag-Te-2-In-1-Te-1-In-2 sequence.


Wu, L   Wang, C   Chen, XL   Li, XZ   Xu, YP   Cao, YG
Ab initio structure determination of new compound Li4CaB2O6
A new compound, Li(4)WaB(2)O(6), has been synthesized by solid-state
   reaction and its structure has been determined from powder X-ray
   diffraction data by direct methods. The refinement was carried out
   using the Rietveld methods and the final refinement converged with R-p
   = 10.4% R-wp = 14.2%, R-exp = 4.97%. This compound belongs to the
   orthorhombic space group Pnnm, with lattice parameters a 9.24036(9)
   Angstrom, b = 8.09482(7) Angstrom, and c = 3.48162(4) Angstrom.
   Fundamental building units are isolated [BO3](3-) anionic groups, which
   are all parallel to the a-b plane stacked along the c-axis. The Ca
   atoms are six-coordinated by the O atoms to form octahedral
   coordination polyhedra, which are joined together through edges along
   the c-axis, forming infinitely long three-dimensional chains. The Li
   atoms have a four-fold and a five-fold coordination with O atoms that
   lead to complex Li-O-Li chains that also extend along the c-axis. The
   infrared spectrum of Li4CaB2O6 was also studied, which is consistent
   with the crystallographic study.


Li, XJ   Kobayashi, T   Zhang, FX   Kimoto, K   Sekine, T
A new high-pressure phase of LiAlO2
A new high-pressure phase of LiAlO2 has been recovered through a shock
   recovery technique at pressures above 9 GPa. This new phase has been
   refined as a tetragonal structure with lattice parameters of a =
   0.38866(8) nm and c = 0.83001(18) nm. Its calculated density is 3.51
   g/cm(3). about 34% denser than gamma-LiAlO2. The aluminum and lithium
   cations in this new phase are six-fold coordinated, as in alpha-LiAlO2,
   and the structure of this new phase is similar to tetragonal LiFeO2.
   This new high-pressure phase is stable at temperatures up to 773 K.


Devi, RN   Wormald, P   Cox, PA   Wright, PA
Novel pillared aluminum ethylene diphosphonate displaying reversible
   dehydration-rehydration behavior
CHEMISTRY OF MATERIALS 16, 2004, 2229-2237.
The novel aluminum ethylene diphosphonate
   Al-2(OH)(2)(H2O)(2)(O3PCH2CH2PO3) has been synthesized hydrothermally..
   It crystallizes in the triclinic space group (P (1) over bar; a =
   8.5977(10), b = 7.0499(3), c = 9.5290(4) Angstrom; alpha = 89.997(21),
   beta = 104.321(8), gamma = 114.225(11)degrees; V =
   506.98(8)Angstrom(3)) with aluminophosphonate layers similar to those
   found in Al(OH)(H2O)CH3PO3 linked via ethylene (-CH2CH2-) groups. The
   solid loses water upon heating in two steps, the first at 100 degreesC
   and the second at 360 degreesC. The first water loss leaves a
   crystalline solid with a framework structure of
   Al-2(OH)(2)(O3PCH2CH2PO3) closely related to that of the parent (C2/ c;
   a = 15.3723(21), b = 6.7613(8), c = 9.7374(13) Angstrom; beta =
   102.392(9)degrees; V = 988.4438 Angstrom(3)) whereas the second water
   loss results in major loss of crystallinity. X-ray powder diffraction
   has been used to determine and refine the structures of the parent and
   intermediate dehydrated phases. The main structural difference is the
   loss of one water molecule bound to aluminum, which changes the metal
   cation's coordination from octahedral to distorted square planar. The
   as-prepared and dehydrated samples have been simulated computationally.
   The transformation has been monitored by in-situ Al-27 MAS NMR
   spectroscopy; octahedral aluminum (delta(iso) = -7.1 ppm; asymmetry
   parameter, eta = 1.0; quadrupolar coupling constant, QCC = 5.4 MHz) is
   converted to 5-fold coordinated aluminum (delta(iso) = 20.7 ppm; eta =
   0; QCC = 5.8 MHz) by heating at 130 degreesC for 1 h. The process is
   fully reversible.


Serre, C   Millange, F   Thouvenot, C   Gardant, N   Pelle, F   Ferey, G
Synthesis, characterisation and luminescent properties of a new
   three-dimensional lanthanide trimesate: M((C6H3)-(CO2)(3)) (M = Y, Ln)
   or MIL-78
A new three-dimensional europium-doped yttrium
   1,3,5-benzenetricarboxylate has been obtained under hydrothermal
   conditions. The structure of MIL-78(Y, Eu) or Y1-xEux((C6H3)-(CO2)(3))
   (x similar to 0.024) has been solved from X-ray powder diffraction data
   (a = 6.941(1) Angstrom, b similar to 14.700(2) Angstrom, c = 8.488(1)
   Angstrom, beta = 107.73(1) degrees, V = 824.9(4) Angstrom(3), space
   group C2/m (no. 12)). Its structure is built up from chains of
   edged-sharing eight-coordinated monocapped square antiprism polyhedra
   and trimesate anions, creating a three-dimensional structure. The same
   structure is formed by replacing yttrium by a rare-earth element. The
   thermal behaviour of MIL-78(Y, Eu) has been investigated using TGA and
   X-ray thermodiffractometry and indicates that MIL-78(Y, Eu) is stable
   up to 450 degreesC. The study of the optical properties of samples
   doped with different rare-earths reveals strong fluorescence under VUV


Cerny, R   Renaudin, G   Favre-Nicolin, V   Hlukhyy, V   Pottgen, R
Mg1+xIr1-x (x=0, 0.037 and 0.054), a binary intermetallic compound with
   a new orthorhombic structure type determined from powder and
   single-crystal X-ray diffraction
The new binary compound Mg1 + xIr1-x (x = 0-0.054) was prepared by
   melting the elements in the Mg:Ir ratio 2:3 in a sealed tantalum tube
   under an argon atmosphere in an induction furnace (single crystals) or
   by annealing cold-pressed pellets of the starting composition Mg:Ir 1:1
   in an autoclave under an argon atmosphere (powder sample). The
   structure was independently solved from high-resolution synchrotron
   powder and single-crystal X-ray data: Pearson symbol oC304, space group
   Cmca, lattice parameters from synchrotron powder data a = 18.46948 (6),
   b = 16.17450 (5), c = 16.82131 (5) Angstrom. Mg1-xIr1-x is a
   topologically close-packed phase, containing 13 Ir and 12 Mg atoms in
   the asymmetric unit, and has a narrow homogeneity range. Nearly all the
   atoms have Frank-Kasper-related coordination polyhedra, with the
   exception of two Ir atoms, and this compound contains the shortest
   Ir-Ir distances ever observed. The solution of a rather complex crystal
   structure from powder diffraction, which was fully confirmed by the
   single-crystal method, shows the power of powder diffraction in
   combination with the high-resolution data and the global optimization


Li, XZ   Chen, XL   Wu, L   Cao, YG   Zhou, T   Xu, Y
Ba3YB3O9: phase transition and crystal structure
A new modification of the compound Ba3YB3O9, beta phase, has been
   attained through solid phase transition from alpha phase at
   1125-1134degreesC. beta-Ba(3)yB(3)O(9) crystallizes in the hexagonal
   space group R3 with cell parameters a = 13.0529(8) (A) over circle, c =
   9.5359(9) (A) over circle. The crystal structure of alpha-Ba3YB3O9 has
   been determined from powder X-ray diffraction (XRD) data. The
   refinement was carried out using the Rietveld methods and the final
   refinement converged with R-p = 8.8%, and R-wp = 11.8% with R-exp =
   5.65%. In its structure, the isolated [BO3](3-) anionic groups are
   parallel to each other and distributed layer upon layer along the
   c-axis. The Y atoms are six-coordinated by the O atoms to form
   octahedra. The result of IR spectrum confirmed the existence of
   [BO3](3-) triangular groups.


Zhang, Y    Li, YD
Red photoluminescence properties and crystal structure of sodium rare
   earth oxyborate
The subsolidus phase relations of the system Y2O3-Na2O-B2O3 are
   reported. There are seven binary compounds and two ternary compounds in
   this system. A new ternary compound Na2Y2B2O7 is identified. The
   structure has been determined for the compound Na2Y2B2O7 from powder
   X-ray diffraction. The lattice constants of P2(1)/c for the compound
   Na2Y2B2O7 are a = 10.5993 (1) (A) over circle, b = 6.2311 (1) (A) over
   circle, c = 10.2247(1) (A) over circle, beta = 117.756(1)degrees and z
   = 4. The structure can be described as being made up of isolated BO3
   triangles and YO8 polyhedra. The photoluminescence properties of Eu
   ion-doped Na2Y2B2O7 and Na3Y(BO3)(2) show strong red-emission of the
   D-5(0)-F-7(2) transitions at 611 and 615 nm, respectively. The results
   of emission spectra are in good agreement with the crystallographic
   study. The relationship between Eu ion content and emission intensity
   is analyzed too.

2004-63  ??

Serre, C   Pelle, F   Gardant, N   Ferey, G
Synthesis and characterization of MIL-79 and MIL-80: Two new
   luminescent open-framework rare-earth dicarboxylates with unusual 1D
   inorganic subnetworks
CHEMISTRY OF MATERIALS 16, 2004, 1177-1182.
Two new three-dimensional europium(III) dicarboxylates, MIL-79 or
   EU5(III)(OH)(9)(H2O)(6)-(O2C-C2H2-CO2)(3)(.)9.5H(2)O, and MIL-80 or
   EU4III(OH)(4)(H2O)(5)(O2C-C2H2-CO2)(4)(.)4H(2)O, have been obtained
   under hydrothermal conditions. Both structures, which have been
   determined using either X-ray powder or single-crystal diffraction
   data, are built-up from unusual complex chains made from clusters of
   eight-, nine-, and ten-coordinated europium(III) polyhedra linked
   through fumarate and maleate dianions. This creates three-dimensional
   structures with either I-D large elongated pore channels (MIL-79) or
   cages (MIL-80) filled in both cases with free water molecules which
   interact with terminal water molecules or apical oxygen atoms from the
   carboxylates. The thermal behavior of MIL-79 has been investigated
   using TGA and X-ray thermodiffractometry and reveals that its
   dehydration leads to an irreversible pore contraction. Study of the
   luminescence properties of the yttrium(III) form of MIL-79 doped with
   europium(III) reveals a significant red-emission upon VUV radiation.
   Crystal data for MIL-79: monoclinic space group C2/m with a = 25.954(1)
   Angstrom, by = 11.014(1) Angstrom, c = 13.247(1) Angstrom, beta =
   119.162(1)degrees, and Z = 4. Crystal data for MIL-80: triclinic space
   group P (1) over bar with a = 10.5770(2) Angstrom, b = 10.6164(2)
   Angstrom, c = 14.9403(3) Angstrom, alpha = 91.624(1)degrees, beta =
   91.120(1)degrees, gamma = 113.892(1)degrees, and Z = 2.


Couhorn, U   Dronskowski, R
Alkali-metal meta-hydroxyphenolates: Syntheses and crystal structures
   from powder X-ray diffraction
M[M-C6H4O(OH)] (M = Li-Cs) have been obtained as highly air- and
   moisture-sensitive powders from reaction mixtures of the appropriate
   alkali metals and resorcinol in thf. Both the potassium and rubidium
   compounds were structurally characterized by means of powder X-ray
   diffraction using the Simulated Annealing method and the Rietveld
   profile refinement technique including C-C/C-O bond distance and C-C-C
   angle restraints. K[m-C6H4O(OH)] (orthorhombic P2(1)2(1)2(1)) forms
   infinite alternating chains of meta-hydroxyphenolate anions connected
   by K-O bonds and short charge-assisted hydrogen bonds, thereby
   generating a three-dimensional network of corrugated layers similar to
   the structure of pure resorcinol. The potassium cations are surrounded
   by a triangle of oxygen and, moreover, coordinated by six adjacent
   phenylene rings to form a distorted octahedron. The complex crystal
   structure of Rb[m-C6H4O(OH)] (monoclinic Pa) is characterized by layers
   of hydrogen-bonded meta-hydroxyphenolate triple units separated by
   corrugated rubidium layers. The three crystallographically different Rb
   atoms are coordinated by three, four, and five oxygens with irregular
   polyhedra, and the rubidiums are also involved in further electrostatic
   interactions by up to eight phenylene rings.


Guillou, N   Livage, C   van Beek, W   Ferey, G
Ab initio determination of a new complex structure (55 non-hydrogen
   atoms) from synchrotron powder data: An uncommon nickel succinate,
   Ni-7(C4H4O4)(4)(OH)(6)(H2O)(3) .  7H(2)O
Ni-7(C4H4O4)(4)(OH)(6)(H2O)(3)(.)7H(2)O, a new layered nickel(II)
   succinate, was prepared hydrothermally (180degreesC, 48 h, autogenous
   pressure) from a 1:1.5:4.1:120 mixture of nickel (II) chloride
   hexahydrate, succinic acid, potassium hydroxide and water. It
   crystallizes in the monoclinic system (space group P2(1)/c, Z = 4) with
   the following parameters a = 7.8597(1) Angstrom, b = 18.8154(3)
   Angstrom, c = 23.4377(4) Angstrom, beta= 92.0288(9)degrees, and V=
   3463.9(2) Angstrom(3). Its structure, which contains 55 non-hydrogen
   atoms, was solved ab initio from synchrotron powder diffraction data.
   It can be described from hybrid organic-inorganic layers, constructed
   from nickel oxide corrugated chains. These chains are built up from
   NiO6 hexameric units connected via a seventh octahedron. Half of the
   succinates decorate the chains, and the others connect them to form the
   layers. The three dimensional arrangement is ensured by hydrogen bonds
   directly between two adjacent layers and via free water molecules.


Zaske, L   Perrin, MA   Daiguebonne, C   Guillou, O
Docetaxel (Taxotere (R) Trihydrate) forms: Crystal structure
   determination from XRPD & XRSCD data
Docetaxel (form A), a stoichiometric hydrate containing three water
   molecules per molecule of drug substance (Taxoteree), is
   thermodynamically stable under ambient conditions of pressure,
   temperature and relative humidity. In order to gain a better
   understanding of docetaxel system at the atomic scale a structural
   study was performed. Due to strong anisotropy of crystals (thin
   plates), the crystal structure of docetaxel (29 degrees of freedom) was
   solved and refined using high resolution XRPD data applying an ab
   initio direct space method. In parallel, an in-depth crystal growth
   study was carried out until single crystals suitable for XRSCD
   structural resolution were obtained: surprisingly, a new polymorph of
   docetaxel, called form B, was isolated.


Albesa-Jove, D   Kariuki, BM   Kitchin, SJ   Grice, L   Cheung, EY   Harris, KDM
Challenges in direct-space structure determination from powder
   diffraction data: A molecular material with four independent molecules
   in the asymmetric unit
CHEMPHYSCHEM 5, 2004, 414-418.


Grzechnik, A   Dmitriev, V   Weber, HP   Gesland, JY   van Smaalen, S
The crystal structures of pressure-induced LiSrAlF6-II and LiCaAlF6-II
The crystal structures of LiCaAlF6-II and LiSrAlF6-II (both P2(1)/c, Z
   = 4) occurring at high pressures and room temperature were studied with
   synchrotron angle-dispersive x-ray powder diffraction in diamond anvil
   cells. The structure of LiSrAlF6-II stable between 1.6 and 3.0 GPa was
   solved with a global optimisation algorithm and group theory
   considerations, and refined with the Rietveld method in the rigid-body
   approximation. It is a distorted variant of the ambient pressure
   polymorph (LiSrAlF6-I, <P(3)over bar1c>, Z = 2), in which each cation
   occupies a deformed octahedral site. LiCaAlF6 transforms to this
   monoclinic polymorph II above about 7 GPa. The differences in the
   high-pressure behaviours of LiCaAlF6 and LiSrAlF6 are discussed by
   considering the ionic radii.


Muangsin, N   Prajuabsook, M   Chimsook, P   Chantarasiri, N
   Siraleartmukul, K   Chaichit, N   Hannongbua, S
Structure determination of diclofenac in a diclofenac-containing
   chitosan matrix using conventional X-ray powder diffraction data
The structure determination of diclofenac embedded in a
   diclofenac-containing chitosan matrix using conventional X-ray powder
   diffraction data is demonstrated. It reveals that sodium diclofenac,
   the starting material in the preparation of a controlled-release
   diclofenac-containing chitosan matrix, changes to diclofenac acid in
   space group C2/c in the matrix. Simple methods were employed for
   handling the sample to obtain X-ray powder diffraction data of
   sufficiently high quality for the determination of the crystal
   structure of diclofenac embedded in chitosan. These involved grinding
   and sieving several times through a micro-mesh sieve to obtain a
   suitable particle size and a uniformly spherical particle shape. A
   traditional technique for structure solution from X-ray powder
   diffraction data was applied. The X-ray diffraction intensities were
   extracted using Le Bail's method. The structure was solved by direct
   methods from the extracted powder data and refined using the Rietveld
   method. For comparison, the single-crystal structure of the same drug
   was also determined. The result shows that the crystal structure solved
   from conventional X-ray powder diffraction data is in good agreement
   with that of the single crystal. The deviations of the differences in
   bond lengths and angles are of the order of 0.030 Angstrom and
   0.639degrees, respectively.


Nowell, H    Attfield, JP
X-Ray and neutron powder diffraction studies of the crystal structure
   of vitamin K-3
NEW JOURNAL OF CHEMISTRY 28, 2004, 406-411.
The previously unknown structure of vitamin K-3 (menadione,
   2-methyl-1,4-naphthoquinone, C11H8O2), a synthetic compound from which
   it is possible to derive the naturally occurring K vitamins, has been
   solved from X-ray powder diffraction data. Solution was achieved using
   simulated annealing and restrained Rietveld refinement, using
   restraints derived from similar known structures. Further refinement
   has been carried out using neutron diffraction data; this confirmed the
   molecular packing and allowed further insight into the structural
   detail with regard to methyl group orientation, thus allowing the
   proposal of an extensive C - H...O hydrogen bonding scheme by reference
   to comparable known structures. The crystal structure consists of
   chains of molecules lying head-to-tail. This study may aid the
   understanding of the biological activity of vitamin K.


Li, XZ   Chen, XL   Jian, JK   Wu, L   Xu, YP   Cao, YG
Thermal stability and crystal structure of beta-Ba3YB3O9
A new compound, beta-Ba3YB3O9, has been attained through solid phase
   transition from alpha-Ba3YB3O9 at high temperatures. Differential
   thermal analysis (DTA) revealed the phase transition at about
   1120degreesC, the melting temperature at about 1253degreesC. Its
   crystal structure has been determined from powder X-ray diffraction
   data. The refinement was carried out using the Rietveld method and the
   final refinement converged with R-p = 10.5% and R-wp = 13.7%. This
   compound belongs to the hexagonal space group R-3, with lattice
   parameters a = 13.0441(1) Angstrom and c = 9.5291(1) Angstrom. There
   are 6 formulas per unit cell and 7 atoms in the asymmetric unit. The
   structure of beta-Ba3YB3O9 is built up from Ba(Y)O-8, BaO6 and YB6O18
   units formed by one YO6 octahedron and six BO3 triangles with shared O


Graham, D   Kennedy, AR   McHugh, CJ   Smith, WE   David, WIF
   Shankland, K   Shankland, N
The crystal structures of three primary products from the selective
   reduction of 2,4,6-trinitrotoluene
NEW JOURNAL OF CHEMISTRY 28, 2004, 161-165
The crystal structures of three primary products from the selective
   reduction of 2,4,6-trinitrotoluene (TNT) have been determined by
   synchrotron X-ray powder diffraction (2-amino-4,6-dinitrotoluene) and
   single crystal X-ray diffraction (4-amino-2,6-dinitrotoluene and
   2-hydroxyamino-4,6-dinitrotoluene). The molecular structure of
   2-amino-4,6-dinitrotoluene, including rotational disorder of the
   6-nitro group, was subsequently detailed to a higher resolution by a
   single-crystal analysis. In contrast to the known structures of TNT,
   the crystal structures of these amino species are dominated by
   hydrogen-bonded sheets connected via ring stacking, whilst that of
   2-hydroxyamino-4,6-dinitrotoluene is dominated by the dual
   hydrogen-bonding acceptor/donator role of the hydroxyamine group.


Kavecansky, V   Mihalik, M   Mitroova, Z   Lukacova, M
Neutron diffraction study of crystal and magnetic structure of
CZECHOSLOVAK JOURNAL OF PHYSICS, 54, suppl D, part 2, 2004, D451-D574.
We present an analysis of the powder neutron diffraction patterns taken
   from the Dy[Fe(CN)(6)]. 4D(2)O at room temperature and in the
   temperature range 1.6 - 40 K. The deuterium positions were localized by
   means of combination of direct and reciprocal space methods and crystal
   structure of the compound was refined using the Rietveld method. The
   knowledge of the complete crystal structure, including the deuterium
   atoms positions, enables further investigation of magnetic structure of
   these types of materials from the neutron diffraction experiments. The
   investigated phase was found to order magnetically bellow 2.8 K. The
   diffraction patterns taken at temperatures 1.76 K - 9.63 K show gradual
   development of magnetic moment as temperature decreases.


Baerlocher, C   McCusker, LB   Prokic, S   Wessels, T
Exploiting texture to estimate the relative intensities of overlapping
Additional information about the relative intensities of reflections
   that overlap in a powder diffraction pattern can be obtained from a
   polycrystalline sample in which the crystallites are preferentially
   oriented. If the data are collected and analyzed appropriately, more
   single-crystal-like reflection intensities can be extracted, and
   thereby more complex structures solved. This 'texture method' was
   implemented initially in reflection mode and its power demonstrated
   with the solution of the 117-atom structure of the hi-h-silica zeolite
   UTD-1F However, the experiment required a minimum of 3 days of
   synchrotron beamtime per sample. In an attempt to reduce the amount of
   beamtime needed and to simplify the experiment itself, a transmission
   mode alternative using an area detector was developed. Details of the
   sample preparation, data collection and data analysis for both
   geometries are described. The solution of the structures of the
   aluminophosphates Mu-9 (R(3) over bar c, a = 14.0696(1) Angstrom, c =
   42.3113(4) Angstrom) and AIPO-M (Pbca, a = 9.7493(1) Angstrom, b =
   29.1668(2) Angstrom, c = 9.3528(1) Angstrom) using reflection and
   transmission mode data, respectively, are provided as examples of the


Bataille, T   Audebrand, N   Boultif, A   Louer, D
Structure determination of thermal decomposition products from
   laboratory X-ray powder diffraction
Ab initio structure determination from powder diffraction data of
   compounds resulting from solid state transformations is still rather
   limited. Two major factors influence the stages of the structure
   elucidation of these solids, i.e. the lower precision in peak position
   for indexing and the strong line overlap for extracting integrated
   intensities. The present study deals with the consideration of these
   two problems for solving the crystal structure of two
   thermal-decomposition inorganic products, Nd(NO3)(3) (.) 4 H2O and
   Pb3O2(NO3)(2). The new features of DICVOL04, as zero shift refinement.
   a priori zero search and tolerance of spurious lines have been used for
   indexing, several phases obtained during the thermal treatment of
   neodymium nitrate hexahydrate. The crystal structures of Nd(NO3)(3) (.)
   4 H2O and Pb3O2(NO3)(2) have been solved with the direct methods and
   the structure model of Pb3O(2)(NO3)(2) has been completed using a
   global optimisation approach. The monoclinic structure of neodymium
   nitrate tetrahydrate [a - 10.1744(4) Angstrom, b = 8.9716(5) Angstrom,
   c = 11.7295(5) Angstrom, beta = 97.384(4)degrees, V = 1061.80
   Angstrom(3), S.G. P2(1)/c] is built from isolated ten-fold coordinated
   Nd polyhedra. The orthorhombic structure of lead oxide nitrate [a =
   7.6034(4) Angstrom, b = 5.7691(4) Angstrom, c = 18.5817(9) Angstrom, V
   = 815.09 Angstrom(3), S.G. Pnma] is built from double chains of
   edge-sharing OPb4 tetrahedra connected by nitrate groups. In order to
   estimate the chance of solving crystal structure of nanocrystalline
   powdered compounds, a comparison of the efficiency of direct methods
   and direct-space approaches is made from powder diffraction patterns
   simulated for various crystallite sizes from the crystal structure of
   the decomposition product gamma-Zn2P2O7.

Perchiazzi, N   Ondrus, P   Skala, R
Ab initio X-ray powder structure determination of parascorodite,
The crystal structure of parascorodite, Fe(H2O)(2)AsO4, has been solved
   ab-initio from powder data. The mineral is trigonal, with space group P
   (3) over bar c1, Z = 6, a = 8.9232(2) Angstrom, c = 9.9296(3) Angstrom.
   The Rietveld refinement was led up to R-p = 4.5%. The structure is
   built up by the same coordination polyhedra found in its dimorph
   scorodite, namely slightly distorted Fe-centred octahedra and
   As-centred tetrahedra, but their connection lead to quite different
   crystal structures for the two polymorphs. Parascorodite structure can
   be described in terms of mixed octahedral-tetrahedral "columns"
   including Fe2 and As polyhedra, running along c, similar to those found
   in ferrinatrite and kaatialaite. These columns are interconnected in a
   threedimensional framework by the sharing of the O1 oxygen between
   [AsO4] tetrahedra and Fe1 octahedra, and by the strong hydrogen bond


Golobic, A   Skapin, SD   Suvorov, D   Meden, A
Solving structural problems of ceramic materials
CROATICA CHEMICA ACTA 77, 2004, 435-446.
Methods for the crystal structure determination from powder diffraction
   data are reviewed with special emphasis on the application to technical
   ceramics. Experimental techniques using other than laboratory X-ray,
   such as synchrotron radiation, neutron and electron beams, are also
   described. As an illustrative example, the crystal structure
   determinations of compounds LaNbTiO6, La0.462Nb0.614Ti0.386O3 and
   La0.37Nb0.889Ti0.111O3 in the ternary system of La2O3-Nb2O5-TiO2 are


Garcia-Cuesta, MC   Lozano, AM   Melendez-Martinez, JJ   Luna-Giles, F
   Ortiz, AL   Gonzalez-Mendez, LM   Cumbrera, FL
Structure determination of nitrato-kappa O-bis[2-(2-pyridyl-kappa
   N)amino-5,6-dihydro-4H-1,3-thiazine-kappa N]copper(II) nitrate via
   molecular modelling coupled with X-ray powder diffractometry
The title copper(II) coordination compound, C18H22CuN8O6S2 {[Cu(NO3)(
   PyTz)(2)] NO3}, was synthesized in the form of small crystals
   unsuitable for structure determination by single-crystal X-ray
   diffractometry. It was therefore characterized by molecular modelling
   coupled with X-ray powder diffractometry [ monoclinic, space group
   P2(1)/n, a = 20.695 (7) Angstrom, b = 8.054 (2) Angstrom, c = 15.157
   (4) Angstrom, beta = 112.09 (2)degrees and R-wp = 0.129]. The procedure
   used to resolve the structure followed direct space methods with a
   'Monte Carlo/parallel tempering' search algorithm, where the starting
   configuration was obtained by means of molecular mechanics. A final
   refinement was performed with the Rietveld method. Bond distances, bond
   angles and torsion angles were compared with those of similar compounds
   deposited in the Cambridge Structural Database.


Belik, AA   Azuma, M   Takano, M   Lazoryak, BI
SrF(e)2(PO4)(2): Ab initio structure determination with X-ray powder
   diffraction data and unusual magnetic properties
CHEMISTRY OF MATERIALS 16, 2004, 4311-4318.
Structure of SrFe2(PO4)(2) was solved ab initio from X-ray powder
   diffraction data (space group P2(1)/c (No. 14); Z = 4; a = 9.3647(2) c,
   b = 6.8518(l) Angstrom, c = 10.5367(2) Angstrom, and =
   109.5140(8)degrees). It has almost linear tetrameric units
   Fe2-Fe1-Fe1-Fe2 which join with each other through common oxygen atoms
   creating a complicated two-dimensional network parallel to the bc
   plane. Specific heat measurements revealed two phase transitions at T-1
   = 7.0 K and T-2 = 11.3 K in zero magnetic field. The phase transition
   at T-2 seems to be a structural phase transition. Magnetization
   measurements showed that, below T-1, SrFe2(PO4)(2) exhibits weak
   ferromagnetism and demonstrates clear ferromagnetic hysteresis loops.
   Above 15 K, Curie-Weiss behavior was observed with an effective
   magnetic moment of 5.23 muB per Fe2+ ion and Weiss constant of -18.9 K.
   Weak ferromagnetic properties below T-1 can be explained by canting of
   antiferromagnetically ordered spins. Several field-induced phase
   transitions were observed in SrFe2(PO4)(2) at low temperatures.


 Peschar, R   Pop, MM   De Ridder, DJA   van Mechelen, JB
   Driessen, RAJ   Schenk, H
Crystal structures of 1,3-distearoyl-2-oleoylglycerol and cocoa butter
   in the beta(V) phase reveal the driving force behind the occurrence of
   fat bloom on chocolate
JOURNAL OF PHYSICAL CHEMISTRY B 108, 2004, 15450-15453.
On the basis of high-resolution synchrotron powder diffraction data,
   crystal structures have been solved for
   1,3-distearoyl-2-oleoylglycerol, a major cis-mono-unsaturated
   triglyceride fraction of cocoa butter, and cocoa butter itself in the
   beta(V) phase. The latter implies that in fact a crystal structure
   model of chocolate in the beta(V) phase has been obtained. The results
   clarify the metastability of the beta(V) phase and explain why fat
   bloom may develop on beta(V)-type chocolate that has been stored at
   temperatures that are too high.

2004-81   ???

Ikeda, T   Akiyama, Y   Oumi, Y   Kawai, A   Mizukami, F
The topotactic conversion of a novel layered silicate into a new
   framework zeolite

2004-82   ??????

Harvey, HG   Herve, AC   Hailes, HC   Attfield, MP
Synthesis, crystal structures, and modifications of novel framework
   gallium diphosphonates
The framework gallium diphosphonates 16, 2004, 3756-3766.
   Ga-2[O3PC2H4PO3](H2O)(2)F-2.-2H(2)O (1) (triclinic, P1, a = 5.0432(2)
   Angstrom, b = 7.2468(3) Angstrom, c = 8.3499(4) Angstrom, alpha =
   107.489(2)degrees, beta = 92.444(2)degrees, gamma = 109.338(2)degrees,
   Z =1) and Ga-2[O3PCH2(C6H4)CH2PO3](H2O)(2)F-2 (2) (triclinic, P1, a =
   4. 9673(l) Angstrom, b = 7. 0898(2) Angstrom, c = 10. 1220(3) Angstrom,
   alpha = 92. 698(2)degrees, beta = 93.153(2)degrees, gamma = 109.
   122(2)degrees, Z = 1) and the solid-solution series
   Ga-2{[O3PCH2(C6H4)CH2PO3](1-x)(HPO3)(2x)}(H2O)(2)F-2 (0 less than or
   equal to X less than or equal to 0. 146) x = 0.541 (3) and x = 0.144
   Ga-2{[O3PCH2(C6H4)CH2PO3](0.853(6))(HPO3)(0.29(1))}(H2O)(2)F-2 (4)
   (triclinic, P1, a = 4.959(2) Angstrom, b = 7.078(2) Angstrom, c =
   10.024(3) Angstrom,alpha = 92.404(5)degrees, beta = 92.955(5)degrees,
   gamma = 109.187(5)degrees, Z = 1) have been synthesized by solvothermal
   methods and their structures determined using X-ray diffraction data.
   All the materials contain linear chains of corner-sharing GaO4F2
   octahedra that are linked by the diphosphonate groups to form framework
   structures. The channels of 1 are found to contain two water molecules
   per unit cell while those in 2 are too narrow to contain extraframework
   species. The apertures created in the phosphite-substituted derivatives
   of 2 (3 and 4) are shown, by crystallographic methods, to be
   considerably larger than those in 2 and, by thermogravimetric methods,
   to create more open structures. The synthetic conditions or form of the
   diphosphonate group are found to play a defining role in the adoption
   of this particular configuration of the inorganic component in the
   reported compounds and provide an additional strategy for the rational
   design of framework hybrid organic -inorganic solids.


Dikarev, EV   Shpanchenko, RV   Andreini, KW   Block, E   Jin, J   Petrukhina, MA
Powder diffraction study of a coordination polymer comprised of rigid
   building blocks: [Rh-2(O2CCH3)(4) .  mu(2)-Se2C5H8-Se,Se
INORGANIC CHEMISTRY 43, 2004, 5558-5563.
The crystal structure of a new hybrid product comprised of two rigid
   building blocks, namely dirhodium(II) tetraacetate, [Rh-2(O2CCH3)(4)]
   (1), and 2,6-diselenaspiro[3.3]heptane, Se2C5H8 (2), has been solved ab
   initio using laboratory source X-ray powder diffraction (XRPD) data.
   The rigid body refinement approach has been applied to assist in
   finding an adequate model and to reduce the number of the refined
   parameters. Complex [Rh-2(O2CCH3)(4).mu(2)Se(2)C(5)H(8)-Se,Se'] (3)
   conforms to the triclinic unit cell with lattice parameters of a =
   8.1357(4), b = 8.7736(4), and c = 15.2183(8) Angstrom, alpha =
   77.417(3), beta = 88.837(3), and gamma = 69.276(4)degrees, V =
   989.66(8) Angstrom(3), and Z = 2. The centrosymmetric P (1) over bar
   space group was selected for calculations. The final values of the
   reduced wR(p), R-p, and chi(2) were calculated at 0.0579, 0.0433, and
   5.95, respectively. The structure of 3 is a one-dimensional zigzag
   polymer built on axial Rh...Se interactions at 2.632(6) Angstrom. The
   2,6-diselenaspiro[3.3]heptane ligand acts as a bidentate linker
   bridging dirhodium units via both selenium atoms. The geometrical
   parameters of individual groups for rigid body refinement have been
   obtained from X-ray powder data for dirhodium(II) tetraacetate (1) and
   from single-crystal X-ray diffraction for diselenium molecule 2. The
   crystal structures of 1 and 2 are reported here for the first time. For
   1 indexing based on XRPD data has resulted in the triclinic unit cell P
   (1) over bar with lattice parameters of a = 8.3392(7), b = 5.2216(5),
   and c = 7.5264(6) Angstrom, alpha = 95.547(10), beta = 78.101(6), and
   gamma = 104.714(13)degrees, V = 309.51(5) Angstrom(3), and Z = 1. The
   final values were wR(p) = 0.0452, R-p = 0.0340, and chi(2) = 1.99. The
   1D polymeric motif built on axial Rh...O interactions of the
   centrosymmetric dirhodium units has been confirmed for the solid-state
   structure of 1. Compound 2,6-diselenaspiro[3.3]heptane (2) conforms to
   the monoclinic space group P2(1)/c with the unit cell parameters of a =
   5.9123(4), b = 19.6400(13), and c = 5.8877(4) Angstrom, beta =
   108.5500(10)degrees, V = 648.15(8) Angstrom(3), and Z = 4.

2004-84 ????

Harvey, HG   Slater, B   Attfield, MP
Rational design of the pore system within the framework aluminium
   alkylenediphosphonate series
We report here on the solvothermal synthesis and crystal structure of
   the hybrid organic-inorganic framework material
   Al-2[O3PC3H6PO3](H2O),F-2.H2O (orthorhombic, Pmmn, a = 12.0591(2)
   Angstrom, b = 19.1647(5) Angstrom, c = 4.91142(7) Angstrom, Z = 4), the
   second member of the Al-2[O3PCnH2nPO3](H2O)(2)F-2.H2O series. The
   structure consists of corrugated chains of corner-sharing AlO4F2
   octahedra in which alternating AlO4F2 octahedra contain two fluorine
   atoms in a trans or a cis configuration. The diphosphonate groups link
   the chains together through Al-O-P-O-Al bridges and through the
   propylene groups to form a three-dimensional framework structure
   containing a one-dimensional channel system. The linkage of the
   corrugated inorganic Al-O-P layers within the structure results in the
   formation of two types of channel that differ in size, shape and
   composition. The smaller channel is unoccupied; the larger channel is
   more elongated and contains two extra-framework water molecules per
   unit cell. A computational investigation into the driving force that
   controls the stacking arrangement of the Al-O-P inorganic layers within
   this series of compounds reveals that the stacking is found to be
   controlled by thermodynamic factors, arising chiefly from the
   conformation of the organic linker molecule used to connect the
   inorganic sheets. It is found that the registration of the inorganic
   layers can be engineered by selecting an appropriate, simple organic
   spacer or linker alkyl chain, where an even number of carbon atoms in
   the alkyl chain directs formation of aligned, stacked, inorganic sheets
   (AAAAAA), and an odd number directs formation of unaligned, stacked
   sheets (ABABAB) and the formation of one or two channel types in the
   resultant structure, respectively. This combination of alkyl-chain
   linkers in conjunction with corrugated inorganic layers is an effective
   tool to rationally design the pore system of hybrid framework materials.


Yang, Z   Chen, XL   Liang, JK   He, M   Chen, JR
The crystal structure of alpha-SrGaBO4
A new compound alpha-SrGaBO4 has been synthesized by solid state
   reaction at high temperatures, and its structure has been solved by
   direct methods from powder X-ray diffraction. alpha-SrGaBO4 has an
   orthorhombic system, Pccn space group, with lattice parameters a =
   15.3154(7) Angstrom, b = 8.9186(4) Angstrom, c = 5.8130(3) Angstrom,
   and Z = 8. The structure consists of infinite chains run parallel to
   the c axis and built up of GaO4 tetrahedral and BO3 triangles. The
   basic unit of these chains is a six - membered Ga2BO8 ring formed by
   two GaO4 tetrahedra and one BO3 triangles. The Sr atom is bonded to
   eight oxygen atoms. The strontium atoms serve to hold the chains
   together through co-ordination with oxygen atoms. DTA curve of
   noncrystalline glassy SrGaBO4 was discussed. The XRD results show no
   phase transition occurs between -173degreesC and 127degreesC.

Azuma, M   Yoshida, H   Saito, T   Yamada, T   Takano, M
Pressure-induced buckling of spin ladder in SrCU2O3
Pressure-induced structural phase transition of spin ladder compound
   SrCu2O3 was investigated by synchrotron X-ray powder diffraction with a
   diamond anvil cell (DAC). The change was characterized by a buckling of
   the Cu2O3 plane in the rung direction of the ladder. The structure of
   the high-pressure phase was found to be essentially the same as that of
   CaCu2O3. Application of an external pressure of 3.4 GPa therefore
   affected the structure in the same manner that the chemical (internal)
   pressure does.


Baranska, M   Lasocha, W   Kozlowski, H   Proniewicz, LM
New solid state Ni(II)-famotidine square-planar complex: powder
   diffraction and spectroscopic studies
Recent potentiometric studies have claimed that Ni(II) forms three
   pH-dependent complexes with famotidine. We isolated two of them from
   the solution; namely the paramagnetic complex NiL with octahedral
   geometry and the diamagnetic complex NiH-L-2 with square-planar
   geometry, The latter compound constitutes the subject of this work. The
   crystal structure of nickel (II) famotidine complex NiC8N7O2S3H13
   discussed here, determined with the powder diffraction method, has
   shown that it belongs to a Pben space group (60) with a, b, c =
   24.328(4), 14.747(2), 7.786(1), V = 2793.6(5) Angstrom 3. R-F and R-wp
   are 16.1% and 15.5%, respectively. Additionally, the UV-VIS, FT-FIR and
   Raman spectroscopic methods were employed to discuss and support the
   structure of the NiH-L-2 complex suggested by X-ray data. The structure
   presented in this work is the second example of the complex of a
   famotidine ligand with a transition metal ion in the solid state. The
   other one, reported from a single crystal X-ray structure of famotidine
   complex with Cu(II), is quite different.


Lin, JH   Sheptyakov, D   Wang, YX   Allenspach, P
Structures and phase transition of vaterite-type rare earth
   orthoborates: A neutron diffraction study
CHEMISTRY OF MATERIALS 16, 2004, 2418-2424.
The structure of vaterite-type rare earth orthoborate (LnBO(3)) has
   long been a subject of interest and controversy. In the :present work,
   the crystal structures of two polymorphs of the vaterite-type rare
   earth orthoborates, i.e., the low- and high-temperature modifications
   of (Y0.92Er0.08)BO3, were solved and refined from neutron powder
   diffraction data. The low-temperature polymorph crystallizes in a
   C-centered monoclinic cell with C2/c space symmetry, the unit cell
   parameters being alpha = 11.3138(3) Angstrom, b = 6.5403(2) Angstrom, c
   = 9.5499(2) Angstrom, and beta = 112.902(1)degrees. The boron atoms in
   the structure are all tetrahedrally coordinated and form the
   three-membered ring borate B3O9 groups. The high-temperature form
   crystallizes in a new structure type in a monoclinic cell with C2/c
   space symmetry, and the unit cell constants alpha = 12.2019(3)
   Angstrom, b = 7.0671(2) Angstrom, c = 9.3424(2) Angstrom, and beta =
   115.347(1)degrees. The borate groups in the high-temperature structure
   are all isolated flat BO3 triangles. As far as the structural chemistry
   is concerned, both structures are different from the typical CaCO3
   vaterite. However, they do share some common features, particularly the
   packing fashion of the cations, which results in similarly looking
   X-ray diffraction patterns as that of the typical vaterite.


Veith, GM   Lobanov, MV   Emge, TJ   Greenblatt, M   Croft, M
   Stowasser, F   Hadermann, J   Van Tendeloo, G
Synthesis and characterization of the new Ln(2)FeMoO(7) (Ln = Y, Dy,
   Ho) compounds
The new compounds Ln(2)FeMoO(7) (Ln = Y, Dy, Ho) have been synthesized
   by solid-state reaction in evacuated silica tubes. The crystal
   structure of Dy2FeMoO7 and Ho2FeMoO7 was determined ab initio by
   simulated annealing in the R(3) over bar space group. Transmission
   electron microscopy study of Y2FeMoO7 revealed an unusual lamellar
   microstructure, composed of blocks with the structure of different
   zirconolite polymorphs. The dominant form corresponds to the
   zirconolite-2M type structure ( space group C2/c) with a partially
   ordered array of Fe and Mo ions. X-Ray near edge spectroscopy data are
   consistent with formally Fe3+ and Mo5+ oxidation states for all
   compounds. Magnetic and transport measurements are reported.


Opozda, EM   Lasocha, W   Wlodarczyk-Gajda, B
Synthesis and characterization of some unsymmetrical Schiff base
   ligands and their nickel(II) complexes incorporating o-phenylenediimine
Six new nickel(II) complexes of the unsymmetrical Schiff base ligands
   derived from o-phenylenediamne were synthesized. These complexes were
   prepared by template and non-template reactions of the precursor
   3-acetyl-4-[N-(2'-aminophenyl)-amino]-3-buten-2-one (HLdegrees) with
   appropriate o-hydroxycarbonyl aromatic compounds, aromatic 1,3-oxo
   aldehydes and 1,3-diketones. The nickel(II) compounds were
   characterized by analytical and spectroscopic methods. Crystal
   structure of complex
   ckel(II) (NiL1) has been determined by X-ray powder diffraction method,
   revealed that the molecules are almost flat, and there are no forces
   other than van der Waals interactions between molecules. The structure
   was solved by global optimisation technique and refined by the Rietveld
   method, obtained R-F and R-wp are 11.6 and 17.4%, respectively. The
   synthesis of a new unsymmetrical nickel(II) tetraazamacrocyclic complex
   is also described.


Bostrom, M   Gemmi, M   Schnelle, W   Eriksson, L
Synthesis, properties and structure determination of
   Nb2O3(SO4)(2) . (1)/4H2O from neutron and synchrotron X-ray
   powder diffraction data
The blue diamagnetic compound Nb2O3(SO4)(2) (.) 1/4H(2)O was
   synthesized by the reaction of niobium metal and boiling sulfuric acid.
   The unit cell was deduced from electron diffraction patterns and the
   crystal structure was solved from X-ray powder diffraction data and
   refined from combined X-ray synchrotron and neutron powder diffraction
   data. Nb2O3(SO4)(2) (.) 1/4H(2)O crystallizes in the space group R-3
   (148) with the cell parameters a = 10.384(2) Angstrom and c = 26.55(2)
   Angstrom in the hexagonal setting. The structure features covalently
   bonded sulfate tetrahedra and niobate octahedra.

2004-92   ?????

Anokhina, EV   Jacobson, AJ
[Ni2O(L-Asp)(H2O)(2)] .  4H(2)O: A homochiral 1D helical chain
   hybrid compound with extended Ni-O-Ni bonding


Jurgens, B   Irran, E   Hoppe, HA   Schnick, W
Phase transition of a dicyanamide with rutile-like structure: Syntheses
   and crystal structures of alpha- and beta-Cd[N(CN)(2)](2)
Cadmium dicyanamide Cd[N(CN)(2)](2) was synthesized through aqueous ion
   exchange at room temperature. A reversible phase transition was
   detected by in situ X-ray powder diffractometry above 55 degreesC. The
   crystal structures of both phases were determined by X-ray powder
   diffraction (beta-Cd[N(CN)(2)](2): T = 22 degreesC, a = 621.60(3), b =
   748.76(4), c = 770.21(5) pm, beta = 91.784(3)degrees, P2(1)/n (no. 14),
   Z = 2, wR(p) = 0.063, R-p = 0.050, R-F = 0.059; alpha-Cd[N(CN)(2)](2):
   T = 150 degreesC, a = 624.62(5), b = 752.92(6), c = 768.30(7) pm, Pnnm
   (no. 58), Z = 2, wR(p) = 0.083, R-p = 0.064, R-F = 0.087). Both
   polymorphs consist of Cd2+ and bent planar [N(CN)(2)](-) ions.
   alpha-Cd[N(CN)(2)](2) crystallizes analogously to rutile and is
   isotypic with M-II[N(CN)(2)](2) (M = Mg, Cr, Mn, Co, Ni, Cu). The
   monoclinic low-temperature polymorph beta-Cd[N(CN)(2)](2) is closely
   related to that of the orthorhombic high-temperature polymorph
   alpha-Cd[N(CN)(2)](2) by a translationengleiche transition of index 2.


Cremer, U   Ruschewitz, U
NaCu5(C-2)(3): The first alkali metal transition metal acetylide with a
   three-dimensional framework structure
By heating the red residue of the reaction of NaC2H and CuI in liquid
   ammonia at 463 K for 30 min in a dynamic vacuum orange polycrystalline
   NaCu5(C-2)(3) is obtained. The crystal structure was solved and refined
   from X-ray powder diffraction data (orthorhombic, Puma, a 732.80(2) pm,
   b = 1099.63(4) pm, c = 726.15(2) pm, Z = 4 R-B = 0.030). It consists of
   a three-dimensional framework of Cu-I and C-2(2-) ions with small
   channels running parallel to [100] and [001]. The sodium ions reside at
   the inter-sections of these channels. The vibrational spectra of
   NaCu5(C-2)(3) show some similarities with the spectra of
   phenylethynylcopper(I), but they are different to those Of Cu2C2.
   Therefore NaCu5(C-2)(3) does probably not represent a crystalline model
   compound for the unknown structure of amorphous Cu2C2.


Hostettler, M   Schwarzenbach, D   Helbing, J   Dmitriev, V   Weber, HP
Structure and SHG of the high pressure phase IV of HgBr2
Angle dispersive X-ray diffraction experiments on mercuric bromide
   (HgBr2) under high pressure up to 11.0 GPa were carried out at room
   temperature using synchrotron radiation. In addition to the already
   known four different phases of HgBr2 in the pressure-temperature range
   of p < 4.5 GPa, 90 < T < 600 K Our observations show the existence of a
   new phase (V) above 9.0 GPa and, together with published material,
   support the phase transition sequence: (I) orthorhombic-(II)
   orthorhombic-(III) monoclinic-(IV) trigonal-(V) trigonal/hexagonal. The
   structure of phase IV with space group symmetry P3 has been determined
   from powder diffraction data. The observation of
   second-harmonic-generation signals confirms the absence of an inversion
   center. The structure of phase IV is a commensurately modulated variant
   of the CdI2 type layer structure, where part of the Hg atoms are
   displaced from the centers of the HgBr6 octahedra by a much as 0.76
   Angstrom in the direction perpendicular to the layers.


Harvey, HG    Attfield, MP
Synthesis, crystal structures, and properties of novel lamellar gallium
CHEMISTRY OF MATERIALS 16, 2004, 199-209.
Three new gallium methylenediphosphonates:
   (C5H5NH)[Ga-2(H2O)(2)(O3PCH2PO3)(O3PCH2-PO3H)] (1) (monoclinic,
   P2(1)/c, a = 11.0848(2) Angstrom, b = 8.4441(2) Angstrom, c = 9.4419(1)
   Angstrom, beta = 104.537(1)degrees, Z = 2),
   [(CH3)(4)N][Ga-2(H2O)(2)(O3PCH2PO)(O3PCH2PO3H)] (2) (monoclinic, C2/c,
   a = 22.1628(8) Angstrom, b = 8.5724(2) Angstrom, c = 9.4455(2)
   Angstrom, beta = 95.486(3)degrees, Z = 4), and
   (C5H5NH)[Ga(H2O)(O3PCH2PO3)] (3) (monoclinic, P2(1)/a, a = 9.5721(7)
   Angstrom, b = 8.6140(6) Angstrom, c = 12.894(1) Angstrom,beta =
   99.961(3)degrees, Z = 4) have been synthesized by solvothermal methods
   in the presence of organocations, and their structures were determined
   using powder (1 and 2) and single-crystal X-ray diffraction data (3).
   All three materials contain a novel corrugated [Ga(H2O)(O3PCH2PO3)](-)
   layer motif composed of octahedral GaO5(OH2) units that are linked
   together by the diphosphonate groups. One of the oxygen atoms of each
   diphosphonate group protrudes into the interlamellar region where it
   hydrogen bonds to adjacent layers in 1 and 2 to form hydrogen-bonded
   framework structures, or to the pyridinium. cations in the lamellar
   material 3. The stacking arrangement of the layers in 1 and 2 is shown
   to be dependent on the organocations present during the synthesis, and
   to form materials with one- or two-types of hydrogen-bonded channels,
   respectively. Material 3 is an intermediate phase isolatable during
   formation of 1 and is convertible to the type of hydrogen-bonded
   framework of 1 by solvothermal, thermal, or solution ion-exchange

Nunes, C
   Suryanarayanan, R   Botez, CE   Stephens, PW
Characterization and crystal structure of D-mannitol hemihydrate
The objectives of this study were (i) to isolate and characterize
   mannitol hydrate, and (ii) to solve its crystal structure from
   high-resolution synchrotron X-ray powder diffraction data. Mannitol
   hydrate was prepared by freeze-drying aqueous mannitol solutions (5%
   w/v) under controlled conditions. X-ray powder diffractometry,
   differential scanning calorimetry, and thermogravimetric analyses
   indicated that mannitol exists as a hemihydrate (C6H14O6 . 0.5H(2)O).
   Synchrotron data were collected on the X3B1 beamline at the National
   Synchrotron Light Source. The simulated annealing program PSSP was used
   to solve the structure, which was subsequently refined by Rietveld
   analysis using the program package GSAS. The compound crystallizes in
   space group P1, with alpha=9.8963 Angstrom, b=10.5424 Angstrom,
   c=4.7860 Angstrom, alpha=102.589degrees, beta = 86.092degrees, and
   gamma =116.079degrees. The unit cell contains two dissimilar D-mannitol
   molecules and one water molecule, forming a hydrogen bonding pattern
   significantly different from that seen in the anhydrous polymorphs.


Dinnebier, R   Sofina, N   Jansen, M
The structure of the high temperature modification of lithium triflate
The high temperature modification of lithium triflate (gamma-LiSO3CF3)
   crystallises in the orthorhombic space group Cmca with the lattice
   parameters a = 6.3022(4), b = 8.6989(5), and c 20.1262(14) Angstrom
   (synchrotron powder diffraction data, T 456 K). The crystal structure
   of gamma-LiSO3CF3 is disordered, in the cationic as well as the anionic
   partial structure, and exhibits double layers of triflate anions with
   the lipophilic CF3-groups facing each other. The lithium ions could not
   be located by the diffraction experiment due to their high mobility.
   The staggered triflate anion is twofold disorderd leading to two
   different positions on top of each other which are tilted to one

2004-99  ???

Zanardi, S   Alberti, A   Cruciani, G   Corma, A   Fornes, V   Brunelli, M
Crystal structure determination of zeolite Nu-6(2) and its layered
   precursor Nu-6(1)


Kirik, SD   Mulagaleev, RF   Blokhin, AI
[Pd(CH3COO)(2)](n) from X-ray powder diff raction data
The water-insoluble title compound,
   [Pd(C2H3O2)(2)](n), was obtained from a nitratopalladium solution and
   acetic acid as a pale-pink powder. Ab initio crystal structure
   determination was carried out using X-ray powder diffraction
   techniques. Patterson and Fourier syntheses were used for atom location
   and the Rietveld technique was applied for the final structure
   refinement. The structure consists of palladium acetate complexes
   connected into polymeric chains running along b, in which two Pd atoms
   are bridged by two acetate groups that are in a cis configuration with
   respect to one another. The unique Pd atom lies on a site with 2/m
   symmetry and the acetate moieties have imposed m symmetry; these are
   joined into infinite chains running along the b direction. The shortest
   Pd...Pd distance in the row is 2.9192 (1) Angstrom. The planes of
   adjacent palladium complexes are inclined towards each other, the angle
   between the planes being approximately 30degrees.


Muhle, C   Nuss, J   Dinnebier, RE   Jansen, M
On potassium tetracyanoplatinate(II), potassium
   tetracyanopalladate(II), and their monohydrates
We have determined the crystal structures of the potassium
   tetracyanoplatinates(II) and -palladates(II), and of their
   monohydrates, by X-ray powder diffraction techniques and single crystal
   structure analysis. K-2[Pt(CN)(4)]: orthorhombic; Pccn; a = 1370.11(2);
   b = 907.09(1); c = 703.91(2) pm; Z = 4; R-F(2) = 0.0903 (N(hkl) = 415).
   K-2[Pt(CN)(4)] . H2O: orthorhombic; Pnna; a = 715.79(4); b = 977.91(6);
   c = 1322.46(8) pm; Z = 4; R(F)(N') = 0.027 (N'(hkl) = 1066).
   K-2[Pd(CN)(4)]: monoclinic; P2(1)/c; a = 433.03(2); b = 782.90(3); c =
   1328.17(6) pm; beta = 93.069(3)degrees; Z = 2; R-p = 0.0583 (N(hkl) =
   352). K-2[Pd(CN)(4)] . H2O: orthorhombic; Pnna; a = 721.48(6); b =
   976.77(8); c = 1326.4(1) pm; Z = 4; R(F)(N') = 0.048 (N'(hkl) = 1137).
   In all examined representatives the anions are stacked one upon the
   other, even though they are tilted in part. The results are completed
   by spectroscopic and thermo analytical investigations.


Ei-Himri, A   Marrero-Lopez, D   Nunez, P
TI Pt2Mo3N and PdPtMo3N: new interstitial nitrides prepared from
   freeze-dried precursors
AB The molybdenum bimetallic and trimetallic nitrides Pt2Mo3N and PdPtMo3N
   have been synthesized by ammonolysis of the stoichiometric amorphous
   precursor, obtained by freeze drying of aqueous solutions of the
   appropriate metal salts. These compounds have been characterized by
   elemental analysis, energy-dispersive analysis of X-rays, X-ray
   diffraction, scanning electron microscopy, transmission electron
   microscopy and thermogravimetry analysis under an oxygen atmosphere.
   Pt2Mo3N and PdPtMo3N crystallize in the cubic space group P4(1)32
   (213), with lattice parameters of a = 6.83586(4) and 6.82542(3)
   Angstrom, respectively, and form with the unusual filled beta-manganese
   structure. These compounds are stable under air up to 580 K, the
   oxidation being complete at 910K.


Lobanov, MV   Greenblatt, M   Caspi, EN   Jorgensen, JD   Sheptyakov, DV
   Toby, BH   Botez, CE   Stephens, PW
Crystal and magnetic structure of the Ca3Mn2O7 Ruddlesden-Popper phase:
   neutron and synchrotron x-ray diffraction study
The crystallographic and magnetic structures of Ca3Mn2O7
   Ruddlesden-Popper phase have been determined by a combination of
   neutron and synchrotron x-ray diffraction. Two-phase behaviour observed
   at room temperature is attributed to an incomplete structural phase
   transition. The magnetic structure was solved in the Cm'c2'(1)
   Shubnikov group with dominant G-type antiferromagnetic order in the
   perovskite bilayers. The temperature evolution of the structural and
   magnetic parameters is presented.


Amami, M   van Smaalen, S   Salah, AB   Helluy, X   Sebald, A
Structural investigation of trimethylammonium tetrachloromercurate
The temperature dependence of the crystal structure of TrMA(2)HgCl(4)
   (TrMA = trimethylammonium) is studied by single-crystal and powder
   X-ray diffraction between 161 and 373 K. Below room temperature, we did
   not find significant changes of the crystal structure. The phase
   transition at 325 K is described by a rotation of one of the two
   independent TrMA(+) cations by 40degrees around the N-H axis, resulting
   in major rearrangements in the network of hydrogen bonds. A large
   change of the volume of the unit cell is found at the phase transition
   at 357 K, resulting in damage to the single crystals. Powder
   diffraction then shows that this transition can be described as a
   alpha-beta transition between the alpha and beta-K2SeO4 structure
   types. Structure refinements employing alternatively restrictions by
   the space group and additional restrictions by the C-3
   non-crystallographic site symmetry for the TrMA(+) cations show that
   significant deviations from C-3 symmetry of the TrMA(+) cations do not
   exist at any temperature. The molecular dynamics and orientational
   disorder were studied by the maximum entropy method applied to the
   X-ray data. The diffraction results are corroborated by temperature
   dependent NMR experiments.

2004-105   ???

Nyman, M   Bonhomme, F   Alam, TM   Parise, JB   Vaughan, GMB
[SiNb12O40](16-) and [GeNb12O40](16-): Highly charged Keggin ions with
   sticky surfaces


Derollez, P   Hernandez, O   Hedoux, A   Guinet, Y   Masson, O
   Lefebvre, J   Descamps, A
Structural and microstructural description of the glacial state in
   triphenyl phosphite from powder synchrotron X-ray diffraction data and
   Raman scattering investigations
The structure and microstructure (refinement of the isotropic size and
   microstrain parameters) of the glacial state in triphenyl phosphite
   (TPP, P(OC6H5)(3)) transformed at 222K have been determined from powder
   synchrotron X-ray diffraction data through a Rietveld and a Le Bail
   refinement, respectively. It is shown that the glacial state is
   composed of crystallites of the stable crystal phase coexisting with
   non-transformed supercooled liquid, the apparent size of the
   crystallites-depending on the aging temperature at which the glacial
   state is isothermally formed, [Phys. Rev. B 60 (1999) 9390]-being equal
   to 329.2(2) Angstrom at 222K. The molecular conformation is slightly
   less mirror-symmetric than the one in the crystal state, and
   correlatively only one of the two unusual weak intermolecular C-H...O
   hydrogen bonds already observed in the latter state is encountered in
   the glacial one. Additional Raman scattering investigations confirm the
   previous result and reveal in addition that no hydrogen bonding
   interaction is observed neither in the glass nor in the liquid states.


Solovyov, LA   Kim, TW   Kleitz, F   Terasaki, O   Ryoo, R
Comprehensive structure analysis of ordered carbon nanopipe materials
   CMK-5 by X-ray diffraction and electron microscopy
CHEMISTRY OF MATERIALS 16, 2004, 2274-2281.
The structure of ordered mesoporous carbon materials CMK-5 was analyzed
   in detail by transmission electron microscopy (TEM) and X-ray
   diffraction (XRD) analysis by applying the recently developed
   continuous density function technique. The materials present
   twodimensional (2-D) hexagonally ordered arrays of carbon nanopipes
   formed within the mesopores of SBA-15 silica templates used for their
   fabrication. The series of CMK-5 carbons were synthesized by applying
   the templates of different pore widths and two carbon precursors:
   furfuryl alcohol and acenaphthene. All the materials were well-ordered,
   exhibiting five distinct XRD reflections, high nitrogen BET specific
   surface areas (about 2500 m(2)/g), and large pore volumes (about 2
   cm(3)/g). TEM analysis and XRD modeling allowed precise determination
   of the mesostructure characteristics such as the nanopipe diameter,
   wall thickness, and shape. Around 15% of the space between the
   nanopipes was found to be occupied by carbon interconnections formed
   inside the complementary pores of the SBA-15 templates. The structure
   parameters determined correlated well with the synthesis procedures and
   were fully consistent with the nitrogen adsorption and
   thermogravimetric data. The differences in the properties and the
   formation mechanisms of the materials synthesized by applying furfuryl
   alcohol and acenaphthene carbon precursors were analyzed based on the
   whole scope of data obtained.


Meshi, L   Talianker, M   Munitz, A
Determination of the structure of UFe2Al10 compound
The atomic structure of a new ternary phase UFe2Al10 appearing in the
   U-Fe-Al system was determined using direct methods applied to X-ray
   powder diffraction data. High resolution electron microscopy combined
   with the methods of crystallographic image processing was used for the
   verification of the structural model. The UFe2Al10 phase is
   orthorhombic and belongs to Cmcm space group, its unit cell contains 40
   Al, eight Fe, and four U atoms. The lattice parameters obtained after
   Rietveld refinement are: a = 8.919 Angstrom, b = 10.208 Angstrom, and c
   = 9.018 Angstrom. The reliability factors characterizing the Rietveld
   refinement procedure are: R-p = 5.9%, R-wp = 8.1%, and R-b = 2.9%.


Chen, XL   He, M   Xu, YP   Li, HQ   Tu, QY
KCaF(CO3) from X-ray powder data 60, 2004, 150-151.
Potassium calcium fluoride carbonate, KCaF(CO3), has been synthesized
   and its structure solved from X-ray powder diffraction data. The K, Ca,
   F and C atoms lie at sites with (6) over bar m2 imposed symmetry and
   the unique O atom has imposed mm site symmetry. The compound consists
   of Ca-F-Ca chains parallel to the c axis and planar CO3 groups
   perpendicular to the c axis, the corners of the hexagonal cell being
   occupied by K+ ions. The compound is not a solid solution, since the
   structure differs from those of both KF and CaCO3.


Cheung, EY   Harris, KDM   Johnston, RL   Kitchin, SJ
   Hadden, KL   Zakrzewski, M
Rationalizing the structural properties of bupivacaine base - A local
   anesthetic - Directly from powder X-ray diffraction data
Bupivacaine belongs to a family of 1-alkyl-2',6'-pipecoloxylidides,
   which has shown promise as reversible action potential blockers that
   can introduce prolonged local anesthetic effects. The crystal structure
   of the free-base form of bupivacaine has been determined directly from
   powder X-ray diffraction data using the Genetic Algorithm technique for
   structure solution, followed by Rietveld refinement. This work further
   emphasizes the scope and utility of ab initio structure solution
   directly from powder X-ray diffraction data for tackling structural
   problems within the biomedical field, leading to opportunities for the
   investigation of structure-property relationships.


Gonzalez-Mendez, LM   Cumbrera, FL   Garcia-Cuesta, MC   Sanchez-Bajo, F
   Ortiz, AL   Higes-Rolando, FJ   Luna-Giles, F
Ab initio structural determination of
   2-(2-pyridyl)imino-N-(2-thiazolin-2-yl)thiazolidine from powder
   diffraction data
MATERIALS LETTERS 58, 2004, 672-678.
Structural determination using X-ray powder diffraction is usually
   restricted to relatively simple structures, although powder diffraction
   data are frequently used to refine, via the Rietveld method,
   approximately known structures. In this work, the relatively complex
   crystalline structure of a compound of high pharmaceutical interest
   (C11H12N4S2) has been firstly ab initio determined from its X-ray
   powder diffraction pattern and subsequently refined by the Rietveld
   method. This refined structure is in excellent agreement with that
   obtained previously from single-crystal data. As a consequence of the
   severe overlapping between adjacent reflections, direct methods failed,
   whereas we obtained good outcomes with 'real space' methods. This work
   shows that within the current state-of-art (hardware, software,
   numerical methods, etc.), relatively complex structures can be afforded
   by means of powder diffraction.


Hu, XR   Yuan, ZQ   Lu, GL
Determination of crystal structures of polymorphic chlorothalonil using
   Monte Carlo simulated annealing and Rietveld refinement
POWDER DIFFRACTION 19, 2004, 325-328.
Crystal structures of types II and III chlorothalonil,
   2,4,5,6-tetrachloro-1,3-dicyanobenzene, (C8Cl4N2) were solved by
   applying Monte Carlo simulated annealing techniques to X-ray powder
   diffraction data and refined using the Rietveld method. Both types of
   chlorothalonil crystallize in monoclinic symmetry (space group P2(1)
   and two molecules per unit cell). Lattice parameters are: a=8.1615(18)
   Angstrom, b=9.4191(19) Angstrom, c=6.4728(14) Angstrom,
   beta=93.7307(64)degrees and V=497.8 Angstrom(3) for type II, and
   a=8.6003(10) Angstrom, b=9.2382(11) Angstrom, c=6.3024(7) Angstrom,
   beta=96.2152(60)degrees and V=498.5 Angstrom(3) for type III. The
   structures of both types of chlorothalonil are stacked by two coplanar
   molecular sheets paralleled to the b-axis. The adjacent two paralleled
   molecules in type II are on the same plane, while those in type III are
   on two different parallel planes.


Dikarev, EV   Chernyshev, VV   Shpanchenko, RV   Filatov, AS   Petrukhina, MA
Bulk material vs. single crystal: powder diffraction to the rescue
DALTON TRANSACTIONS iss 24, 2004, 4120-4123.
The crystal structure of bulk microcrystalline material obtained by
   interaction of two rigid building blocks, namely dirhodium(II)
   tetra(trifluoroacetate), [Rh-2(O2CCF3)(4)], and bis(4'-pyridyl)
   diphenylsilane, (C6H5)(2)Si(C5H4N)(2), has been solved ab initio using
   X-ray powder diffraction data. The title product of the 1:1
   composition, [Rh-2(O2CCF3)(4).(mu(2)-(C6H5)(2)Si(C5H4N)(2))], is a
   one-dimensional zigzag polymer built on axial Rh...N interactions
   averaged at 2.16 Angstrom. Its structural characterization complements
   the previously reported product of the 2:1 composition obtained from
   the same reaction, namely
   {[Rh-2(O2CCF3)(4)](2).(mu(4)-(C6H5)(2)Si(C5H4N)(2))}. The latter has a
   2D layered network revealed by the single crystal diffraction study. A
   combination of powder and single crystal X-ray techniques is shown to
   be methodologically important and complementary for understanding of
   product assembling in the system.


Evans, IR   Howard, JAK   Szecsenyi, KM   Leovac, VM   Jacimovic, ZK
Synthesis, characterization and crystal structure of a novel Ni(II)
   complex, Ni(L-H)(2) (L=3,5-dimethyl-1-thiocarboxamidopyrazole)
A new complex, Ni(L-H)(2), L = 3,5-dimethyl-1-thiocarboxamidopyrazole,
   has been synthesized and characterized by IR spectroscopy, magnetic and
   electrical measurements. Its crystal structure was solved from powder
   X-ray diffraction data. The compound crystallizes in space group P (1)
   over bar with two independent half-molecules containing Ni(II)
   coordinated by four nitrogen atoms in a square-plane. The packing
   pattern consists of two stacks of parallel molecules mutually tilted at
   an angle of 118degrees.

2004-115  ???

Rubin-Preminger, JM   Bernstein, J   Harris, RK   Evans, IR   Ghi, PY
Variable temperature studies of a polymorphic system comprising two
   pairs of enantiotropically related forms: [S,S]-ethambutol
CRYSTAL GROWTH & DESIGN 4, 2004, 431-439.
Of the four known polymorphs of [S,S] -ethambutol dihydrochloride, two
   transform in an enantiotropic single-crystal-to-single-crystaI phase
   transformation from Form II to Form I on heating. The crystal
   structures of these two forms have been solved and compared. Because
   the other two forms are metastable and are only obtained from the melt,
   single-crystal data could not be obtained on them. However, all four
   forms have been characterized, and their relative thermodynamic
   relationships have been investigated by variable-temperature
   solid-state C-13 NMR, variable-temperature powder X-ray diffraction
   studies, differential scanning calorimetry, and optical microscopy.


Money, VA   Evans, IR   Elhaik, J   Halcrow, MA   Howard, JAK
An X-ray powder diffraction study of the spin-crossover transition and
   structure of bis (2,6-dipyrazol-1-ylpyrazine)iron(II) perchlorate
The crystal structure of the iron(II) spin-crossover compound
   [Fe(C10H8N6)(2)](ClO4)(2) in the high-spin state has been solved from
   powder X-ray diffraction data using the DASH program and refined using
   Rietveld refinement. The thermal spin transition has been monitored by
   following the change in unit-cell parameters with temperature. The
   title compound has been found to undergo a crystallographic phase
   change, involving a doubling of the crystallographic a axis, on
   undergoing the spin transition.


Mahe, N   Bataille, T
Synthesis, crystal structure from single-crystal and powder x-ray
   diffraction data, and thermal behavior of mixed potassium lanthanide
   squarates: Thermal transformations of layered
   [Ln(H2O)(6)]K(H2C4O4)(C4O4)(2) into pillared LnK(C4O4)2 (Ln = Y, La,
   Gd, Er)
INORGANIC CHEMISTRY 43, 2004, 8379-8386.
A new series of mixed potassium and rare-earth squarates,
   [Ln(H2O)(6)]K(H2C4O4)(C4O4)(2) (Ln = Y, La, Gd, Er), has been
   synthesized and structurally characterized from single-crystal X-ray
   diffraction and spectroscopic analyses. The yttrium-based compound
   crystallizes with a monoclinic symmetry, space group C2/c [a =
   8.3341(2) Angstrom, b = 37.7094(g) Angstrom, c = 11.7195(3) Angstrom,
   beta = 90.3959(9)degrees, V = 3683.1(2) Angstrom(3), Z = 8]. The
   structure is built from layers maintained together via hydrogen bonds.
   Within a layer, squarate ligands act as linkers between lanthanide and
   potassium cations. The thermal decomposition of the precursors has been
   studied by powder thermodiffractometry and thermal analyses. It is
   shown that crystalline intermediate phases are formed during the
   degradation. Among them, unprecedented mixed anhydrous squarates,
   LnK(C4O4)(2), could be isolated. The crystal structure of the Y
   compound has been solved ab initio from X-ray powder diffraction data,
   using direct-space methods [a = 6.2010(5) Angstrom, c = 11.639(l)
   Angstrom, V = 447.55 Angstrom(3), Z = 2]. The structure consists of
   layers of edge-sharing YO8 and KO8 antiprisms, pillared by
   mu(8)-squarate groups. The end of the precursor decomposition is marked
   by the formation of cubic sesquioxides Ln(2)O(3), including lanthanum


Degtyareva, O   McMahon, MI   Nelmes, RJ
Pressure-induced incommensurate-to-incommensurate phase transition in
PHYSICAL REVIEW B 70, 2004, 184119.
An incommensurate composite phase with a monoclinic host-guest
   structure, designated Sb-IV, is found between the previously known Sb-I
   and Sb-II phases, and an incommensurate to incommensurate transition
   between phases II and IV is described. The monoclinic Sb-IV phase is
   observed on both pressure increase between 8.2 and 9.0 GPa and on
   pressure decrease between 8.0 and 6.9 GPa. The full structure of Sb-IV,
   including a determination of the structural modulations of the host and
   guest components, is reported from x-ray powder diffraction data. The
   high-pressure phase of arsenic, As-III, is shown to have the same
   monoclinic composite structure.


Dacheux, N   Clavier, N   Robisson, AC   Terra, O
   Audubert, F   Lartigue, JE   Guy, C
Immobilisation of actinides in phosphate matrices
COMPTES RENDUS CHIMIE 7, 2004, 1141-1152.
In the field of the immobilisation of high-activity-level and long-life
   radwaste (HAVL) for a deep underground repository, several phosphate
   matrices were already proposed as good candidates to delay the release
   of actinides in the near-field of such disposal. Among them, thorium
   phosphate-diphosphate (TPD), monazites/brabantites, britholites, and
   TPD/monazite composites were extensively studied. The synthesis of
   samples doped with actinides (Th, U...) through wet and dry chemistry
   methods then their complete characterisation are reported. Their
   chemical durability is also examined. These materials appear as
   promising matrices to immobilise tetravalent and/or trivalent


Brandel, V   Dacheux, N
Chemistry of tetravalent actinide phosphates - Part I
actinide (IV) phosphate; phosphates of tetravalent cations; thorium
   phosphate; uranium phosphate; neptunium phosphate; plutonium phosphate;
   protactinium phosphate
The chemistry and crystal structure of phosphates of tetravalent
   cations, including that of actinides was reviewed several times up to
   1985. Later, new compounds were synthesized and characterized. In more
   recent studies, it was found that some of previously reported phases,
   especially those of thorium, uranium and neptunium, were wrongly
   identified. In the light of these new facts an update review and
   classification of the tetravalent actinide phosphates is proposed in
   the two parts of this paper. Their crystal structure and some chemical
   properties are also compared to non-actinide cation phosphates.


Martinez-Garcia, R   Reguera, E   Rodriguez, J   Balmaseda, J   Roque, J
Crystal structures of some manganese(II) and cadmium hexacyanoferrates
   (II,III) and structural transformations related to the sorption of
POWDER DIFFRACTION 19, 2004, 255-264.
Mn2+ and Cd2+ form a family of isostructural hexacyanoferrates(II,III).
   Their crystal structures, including those of mixed compositions
   containing K+ and Cs+ as charge balance cations, were resolved and
   refined from XRD powder patterns. The crystal structures of
   M-3[Fe(CN)(6)](2) .  xH(2)O and MCs2[Fe(CN)(6)] (where M=Mn, Cd)
   were refined in the space group Fm3m. The mixed salts,
   MK2[Fe(CN)(6)] . (2)H(2)O, were found to be orthorhombic (space
   group Pmn2(1)). The orthorhombic structure results from a local
   distortion due to monohydrated potassium ions located in interstitial
   sites. On ionic exchange in an aqueous solution containing Cs+, the
   orthorhombic distortion disappears and the cubic cell is obtained. Cs+
   is a large ion, which practically fills the available interstitial
   voids stabilizing the cubic structure. In solutions of K+ and Cs+ the
   single salts, M-2[Fe(CN)(6)] .  8H(2)O (monoclinic P2(1)/n) also
   transform, in this case liberating M2+ ions and forming the
   corresponding mixed salts. An analogous but slow structural
   transformation was also observed in the anhydrous forms of these single
   salts. These structural transformations could be relevant to the use of
   these compounds as ion exchangers and particularly for the sorption of
   Cs-137(+) from radioactive waste solutions. The XRD data were
   complemented with structural information from infrared (IR), Mossbauer
   and water vapor adsorption techniques.


Martinez-Garcia, R   Reguera, E   Balmaseda, J   Ramos, G   Yee-Madeira, H
On the crystal structures of some nickel hexacyanoferrates (II,III)
POWDER DIFFRACTION 19, 2004, 284-291.
The crystal structures of some nickel hexacyanoferrates (II, III),
   including mixed compositions containing Na+, K+ and Cs+, were resolved
   and refined from XRD powder patterns. Data from infrared, Mossbauer and
   adsorption techniques provided complementary structural information.
   The crystal structures of Ni-3[Fe(CN)(6)](2) .  16H(2)O and
   NiCS2[Fe(CN)(6)] were refined in space group Fm3m.
   NiNa2[Fe(CN)(6)] .  2H(2)O and NiK2[Fe(CN)(6)] .  2H(2)O
   were found to be orthorhombic (space group Pmn2(1)). This structure
   (Pmn21) results from a distortion around the alkali ion, which appears
   as a monohydrated interstitial species. On ionic exchange in an aqueous
   solution containing Cs+, the orthorhombic distortion disappears and the
   cubic cell is obtained. Cs+ is a large cation and space is not
   available for interstitial water molecules. This orthorhombic model is
   also supported by the Mossbauer spectra of the ferrous analogs,
   FeK2[Fe(CN)(6)] .  xH(2)O and Fe[Pt(CN)(6)].


Heymann, G   Beyer, K   Huppertz, H
High-temperature synthesis, crystal structure, and properties of the
   new sodium rare-earth oxide borates Na2RE2(BO3)(2)O (RE = Dy, Ho)
The new monoclinic oxide borates Na2RE2(BO3)(2)O (RE = Dy, Ho) were
   synthesized using standard solid-state reactions in the temperature
   range 900-950 degreesC. They are isotypic to the known phases
   Na2RE2(BO3)(2)O (RE = Y, La, Nd, Sm-Gd, Er). The single crystal X-ray
   structure determination of Na2Dy2(BO3)(2)O revealed: P2(1)/c, a
   1063.9(l), b = 626.2(l), c = 1025.3(1) pm, beta = 117.76(1)degrees, Z =
   4, Rl = 0.0221, wR2 = 0.0402 (all data). The corresponding lattice
   parameters of Na2HO2(BO3)(2)O determined from powder data are a =
   1061.2(5), b = 623.7(2), c = 1022.5(3) pm, and 0 = 117.7(1)degrees. The
   structure consists of infinite sheets of REO8-polyhedra in the
   bc-plane, which are seperated by sodium atoms. The BO3-groups are
   isolated forming layers in the bc-plane. The results of IR-
   spectroscopic investigations, temperature-resolved in-situ
   powder-diffraction measurements, and DTA/TG measurements on
   Na2Dy2(BO3)20 are also presented.


Ardizzoia, GA   Brenna, S   Castelli, F   Galli, S
   LaMonica, G   Masciocchi, N   Maspero, A
Metal imidazolato polymers: synthesis, characterization and crystal
   structure of new silver(I) triphenylphosphine derivatives
POLYHEDRON 23, 2004, 3063-3068.
When the polymeric complex [Ag(im)](n) (Him = imidazole) is reacted
   with PPh3 (PPh3 = triphenylphosphine), it yields the
   [Ag-2(mu(2)-im)(2)(PPh3)(3)] and [Ag(mu(2)-im)(PPh3)(2)](n) species,
   shown to contain wavy chains of metal ions, singly bridged by
   N,N'-exobidentate imidazolate ligands. The former, crystallised as the
   CH2Cl2 solvate, contains two non-equivalent silver(I) ions, differing
   in the number of coordinated phosphines (one, in trigonal planar
   stereochemistry, or two, having tetrahedral geometry). The latter has a
   unique independent silver(I) ion in a tetrahedral environment, with two
   coordinated PPh3 ligands. The reactivity of known silver(I) azolates
   with PPh3, as well as the solution behaviour and (when available) the
   crystal structures of the corresponding derivatives are taken into
   consideration for a due comparison.


Gredin, P   Labeguerie, J   Pierrard, A   Vaulay, MJ   de Kozak, A
Synthesis and structural characterization of K0.33Gd0.67F2.33 (KGd2F7)
   and K0.31Gd0.69F1.84O0.27
SOLID STATE SCIENCES 6, 2004, 1221-1228.
K0.33Gd0.67F2.33(KGd2F7) is synthesized by solid state reaction between
   KF and GdF3 at different temperatures (600, 700, 800 and 900 degreesC).
   For all temperatures, the crystal structure of K0.33Gd0.67F2.33 derives
   from that of the fluorite type. Nevertheless when the synthesis
   temperature increases, the X-ray powder pattern exhibits new
   superstructure diffraction lines. This feature is attributed to an
   anionic and cationic ordering. A structural model is elaborated and the
   crystal structure at 700 degreesC is determined by the Rietveld method.
   The oxyfluoride K0.31Gd0.69F1.83O0.27 is synthesized using a sol-gel
   route. Its crystal structure is close to that of K0.33Gd0.67F2.33 and
   differs only by a new anionic and cationic ordering. K0.33Gd0.67F2.33
   and K0.31Gd0.69F1.83O0.27 are then just particular compositions of the
   solid solution formulated K1-xGdxF1+2x-2yOy.


Broach, RW   Sinkler, W   Patton, RL   Mezza, TM   Gatter, MG
Technique integration applied to structure solution: The case of UZM-5.
   Details of the structure, faulting and templating
   MATERIALS, PTS A - C 154, 2004, 1188-1196.
The structure solution of the new zeolite framework UZM-5 is reviewed.
   It is shown how the structure solution emerges from integration of a
   number of zeolite characterization techniques such as powder X-ray
   diffraction, transmission electron microscopy, infrared spectroscopy
   and McBain adsorption. In addition to the ideal structure, faulting is
   evident in both powder X-ray diffraction and transmission electron
   microscopy. Details of the surface structure and faulting on the (001)
   planes are described.


Hoyos, D   Paillaud, JL   Guth, JL
Synthesis and structure determination of a novel lithium copper
   vanadate LiCu2VO4(OH)(2)
SOLID STATE SCIENCES 6, 2004, 1359-1364.
A novel lithium copper vanadate LiCu2VO4(OH)(2) (I) and Volborthite
   Cu3V2O7(OH)(2) are two phases obtained at 170degreesC by hydrothermal
   synthesis during the study of the CuO; V2O5; U2O; H2O system. Compound
   (1) crystallizes in the orthorhombic system, with the space group
   P2(1)2(1)2(1) (No. 19) and with the unit-cell parameters a = 9.6086(2)
   Angstrom, b = 8.4482(2) Angstrom, c = 5.8938(1) Angstrom. The structure
   was determined from powder by an "ab initio" method using the EXPO
   software and refined with GSAS, a Rietveld refinement package.
   Wave-like layers of rutile-type copper chains sharing vertex with the
   neighbor chains, are linked into a three-dimensional framework by rows
   of alternating tetrahedra of vanadium and trigonal bipyramids of
   lithium which share edges and vertices with the copper octahedra.


Chernyshev, VV   Stephens, PW   Yatsenko, AV   Ryabova, OB   Makarov, VA
Structural characterization of prazosin hydrochloride and prazosin free
three-dimensional solid-state structures of prazosin hydrochloride,
   C19H22N5O4+ . Cl- (A), and prazosin free base, C19H21N5O4 (B), have
   been determined by synchrotron X-ray powder diffraction. A and B
   crystallize in triclinic P-1 and monoclinic Cc space groups,
   respectively, with one structural unit per asymmetric part. In A and B,
   the prazosin molecule adopts different conformations, which do not
   correspond to those obtained by DFT optimizations of protonated and
   free prazosin.


Nomiya, K   Yoshizawa, A   Tsukagoshi, K   Kasuga, NC   Hirakawa, S   Watanabe, J
Synthesis and structural characterization of silver(I), aluminium(III)
   and cobalt(II) complexes with 4-isopropyltropolone (hinokitiol) showing
   noteworthy biological activities. Action of silver(I)-oxygen bonding
   complexes on the antimicrobial activities
Through two unequivalent oxygen donor atoms of the hinokitiol (Hhino;
   C10H12O2; 4-isopropyltropolone) ligand that showed noteworthy
   biological activities, the dimeric, silver(l)-oxygen bonding complex
   [Ag(hino)](2) 1, the monomeric aluminium(III) complex [AI(hino)(3)] .
   0.5H(2)O 4 and the cobalt(II) complex "[Co(hino)(2)](2) . H2O" 6 were
   synthesized and characterized with elemental analysis,
   thermogravimetric and differential thermal analysis (TG/DTA), FTIR and
   solution (H-1 and C-13) NMR spectroscopy. The crystal structure of 1
   was determined by Rietveld analysis based on X-ray powder diffraction
   (XPD) data and those of [Al(hino)(3)] . MeOH 4a and
   [Co(hino)(2)(EtOH)](2) 6a, being obtained as yellow block crystals and
   red platelet crystals, respectively, by crystallization of 4 and 6,
   were determined by single-crystal X-ray analysis. The antimicrobial
   activities of 1, 4 and 6, evaluated with minimum inhibitory
   concentration (MIC; mug ml(-1)), were compared with those of other
   metal complexes (M = Na, Li, Cs, Ca, V, Zn) with the hino(-) ligand.
   The antimicrobial activities observed in the alkali-metal salts
   strongly suggested that they were attributed to the effect of the
   anionic hino- species. The antimicrobial activities of 1 were
   significantly enhanced, whereas those of other metal complexes were
   suppressed, compared with those of the neutral Hhino and anionic hino-
   molecules. The antimicrobial activities observed in I were comparable
   with those of other recently found silver(l)-oxygen bonding complexes,
   the ligands of which had no activity. Thus, it is proposed that the
   antimicrobial activities of the silver(l)-oxygen bonding complexes are
   due to a direct interaction or complexation of the silver(l) ion with
   biological ligands such as protein, enzyme and membrane, and the
   coordinating ligands of the silver(l) complexes play the role of a
   carrier of the silver(l) ion to the biological system.

2004-130 ???

Clavier, N   Dacheux, N   Martinez, P   de Kerdaniel, EDF
   Aranda, L   Podor, R
Sintering of beta-thorium-uranium(IV) phosphate-diphosphate solid
   solutions from low-temperature precursors
CHEMISTRY OF MATERIALS 16, 2004, 3357-3366.
Pure and single phase thorium-uranium(IV) phosphate-diphosphate
   beta-TUPD (orthorhombic form) dense pellets were prepared by two wet
   chemical routes from low-temperature precursors. The first method was
   based on the "direct evaporation" of a mixture containing tetravalent
   actinides and phosphoric acid while the second one involved the initial
   precipitation of the thorium-uranium(IV) phosphate-hydrogenphosphate
   hydrate (TUPHPH). Both methods led to single phase sintered samples
   following a two-step procedure using a uniaxial pressing at room
   temperature and then a heat treatment at high temperature. The
   dilatometric study and the determination of the linear shrinkage of the
   pellets showed that the best densification of the samples prepared via
   the "precipitation" method was obtained after heating the raw pellet at
   1250 degreesC for 5 h, for initial uranium amount lower than 44.5 wt
   %(U). For samples prepared via "direct evaporation", the heat treatment
   must be prolonged for at least 15 h at this temperature. Moreover, the
   complete characterization of the samples (EPMA, and so forth) confirmed
   that the homogeneity of the samples was significantly improved when
   using TUPHPH as a precursor, probably due to the better reactivity of
   the initial powder (higher specific surface area, smaller grain size,
   and so forth). Several leaching tests were performed in various acidic
   media and in natural waters on beta-TUPD sintered samples. All the
   corresponding normalized dissolution rates remained low (10(-6) to
   10(-5) g/(m(2) day)) even in aggressive media which confirms the high
   chemical durability of beta-TUPD, thus enhancing the potential use of
   this ceramic in the field of the efficient immobilization of
   tetravalent actinides.


Bull, CL   McMillan, PF   Soignard, E   Leinenweber, K
Determination of the crystal structure of delta-MoN by neutron
We have determined the crystal structure of ordered hexagonal delta-MoN
   by use of powder X-ray diffraction and time-of-flight neutron
   diffraction. A disordered variety of the compound was first prepared by
   high-temperature ammonolysis Of MoCl5. This material has hexagonal
   symmetry with the space group P6(3)mc with a = 2.87(2) and c = 2.81 (1)
   Angstrom. Upon high pressure annealing, the N-atoms become ordered and
   the unit cell doubles in size: a = 5.73659(10) and c = 5.61884(17)
   Angstrom. The superconducting transition temperature increases from 4K
   in the disordered compound to 12.1 K in the ordered phase.


Ling, CD   Johnson, M
Modelling, refinement and analysis of the "Type III"
   delta-Bi2O3-related superstructure in the Bi2O3-Nb2O5 system
The structure of the "Type III" delta-Bi2O3-related superstructure
   phase in the system Bi2O3-Nb2O5 is presented. A starting model was
   constructed by considering the crystal-chemistry of the system in the
   context of symmetry constraints determined by electron diffraction.
   After applying initial distortions, this could be Rietveld-refined
   against a combination of synchrotron X-ray and time-of-flight neutron
   powder diffraction data. The undistorted starting model was
   independently optimized using solid-state ab initio energy
   calculations, giving a fully optimized structure in excellent agreement
   with that obtained by Rietveld refinement. This dual approach both
   validates the structure and demonstrates the value of combining
   accurate total energy calculations with traditional refinement
   techniques for the solution of complex structures using powder
   diffraction data. The structure (Bi94Nb32O221, Z = l, I (4) over bar m2
   (#119), a = 11.52156(18), c = 38.5603(6) A) consists of interacting
   corner-connected strings of NbO6 octahedra along <110>(F) directions of
   the FCC subcell, and can be described as a hybrid of fluorite and
   pyrochlore types.


Hong, SB   Lear, EG   Wright, PA   Zhou, WZ   Cox, PA
   Shin, CH   Park, JH   Nam, IS
Synthesis, structure solution, characterization, and catalytic
   properties of TNU-10: A high-silica zeolite with the STI topology
A high-silica zeolite (Si/Al = 7.1) with the STI framework topology,
   denoted TNU-10, has been synthesized in the presence of
   1,4-bis(N-methylpyrrolidinium)butane and Na+ cations as
   structure-directing agents, and its structure in the proton form has
   been refined against laboratory powder X-ray data in space group Fmmm
   (a = 13.533(1) Angstrom, b = 17.925(2) Angstrom, c = 17.651(2)
   Angstrom). The space group symmetry is supported by electron
   diffraction and energy minimization studies. The as-made and proton
   form of TNU-10 are extensively characterized by elemental and thermal
   analyses, scanning electron microscopy, N-2 adsorption, multinuclear
   solid-state NMR, IR, and temperature-programmed desorption of ammonia,
   and the location of the organic structure-directing agent in the
   channel system is determined by molecular modeling. The catalytic
   properties of H-TNU-10 and Co-TNU-10 are evaluated for the skeletal
   isomerization of 1-butene to isobutene and the selective reduction of
   NO with methane, respectively. When compared to H-ferrierite, a low
   selectivity to isobutene is observed for H-TNU-10. However, it is found
   that Co-TNU-10 exhibits a maximum NO conversion of 93% at 823 K under
   conditions of high concentrations of methane (16000 ppm) and water
   vapor (10%) and in the presence of 2.6% O-2, which is considerable
   higher than even the value (74%) obtained from Co-ferrierite, known as
   the best catalyst for this reaction, under the identical conditions.


Mogare, KM   Friese, K   Klein, W   Jansen, M
Syntheses and crystal structures of two sodium ruthenates: Na2RuO4 and
Na2RuO4, prepared from Na2O2 and RuO2 via high oxygen pressure
   synthesis, crystallises monoclinic in space group P2(1)/c (a =
   10.721(6), b = 7.033(4), c = 10.871(6) Angstrom, beta =
   119.10(4)degrees, Z = 8, 2503 unique reflections, R-1 = 0.049).
   Structure determination from single crystal data shows that the
   compound consists of infinite chains of RuO5 trigonal bipyramids
   connected through their axial vertices. The Na cations connect the
   pseudohexagonally packed (1)(infinity)[RuO3O2/2] chains and are
   coordinated by six or seven oxygen atoms, respectively. The compound
   exhibits an one-dimensional spin system with mu = 2.80 mu(B) and Theta
   = -222 K and a three-dimensional antiferromagnetic ordering below 50 K.
   Na2RuO3 was obtained from Na2RuO4 at 850 degreesC under a flow of
   argon. The structure was determined from X-ray powder diffraction. It
   is closely related to the alpha-NaFeO2 and the Li2SnO3 structure types,
   layered variants of the NaCl type. In Na2RuO3 the Na and Ru atoms are
   partially disordered. This partially disordered state was approximated
   by a Rietveld refinement of two superimposed structural models (model
   I: R (3) over bar m, a = 3.12360(5), c = 16.0370(4) Angstrom, Z = 2;
   model II: C2/c, a = 5.4141(4), b = 9.3663(6), c = 10.8481(4) Angstrom,
   beta = 99.636(9)degrees, Z = 8).

2004-135  ???

Zima, V   Melanova, M   Benes, L   Trchova, M   Dybal, J
Intercalation of gamma-butyrolactone into vanadyl phosphate and niobyl
Intercalation compounds of vanadyl phosphate and isostructural niobyl
   arsenate with gamma-butyrolactone, VOPO4.C4H6O2 and NbOAsO4.C4H6O2,
   respectively, were prepared from corresponding propanol intercalates by
   molecular exchange in a microwave field. The prepared intercalates were
   characterized using powder X-ray diffraction, density measurements, and
   thermogravimetric analysis. Infrared and Raman spectra indicate a
   coordination of the carbonyl oxygen atom of the gamma-butyrolactone
   molecule to the vanadium or niobium atom of the host structure. Quantum
   mechanical calculations at the ab initio level confirm the proposed
   structure in which the I-butyrolactone guest molecules are arranged
   with the plane of the ring perpendicular to the host layers and are
   anchored to the layers through the carbonyl oxygen atom coordinated to
   the transition metal atom of the host.


Dova, E   Peschar, R   Sakata, M   Kato, K   Stassen, AF
   Schenk, H   Haasnoot, JG
Structures of Fe-II spin-crossover complexes from synchrotron
   powder-diffraction data
Crystal structure determination and analysis have been carried out for
   the two spin-crossover compounds [Fe(teeX)(6)](BF4)(2) (teeX is
   haloethyltetrazole; X = I: teei; X = Br: teeb), in both their high-spin
   (near 300 K) and their low-spin states (T = 90 K), using
   high-resolution powder-diffraction data collected at the ESRF
   (Grenoble, France) and SPring8 (Japan) synchrotron radiation
   facilities. The structures of teei have been solved using various
   direct-space structure determination techniques (grid search genetic,
   algorithm and parallel tempering) and refined with the Rietveld method
   using geometrical restraints. In the case of teeb, a structural model
   was found but a full refinement was not successful because of the
   presence of a significant amount of an amorphous component. Analysis of
   the structures (space group P2(1)/c, Z = 2) and diffraction data, and
   the absence of phase transitions, show the overall structural
   similarity of these compounds and lead to the conclusion that the
   gradual spin-crossovers are likely to be accompanied by small
   structural changes only.


Xu, HW   Nyman, M   Nenoff, TM   Navrotsky, A
Prototype sandia octahedral molecular sieve (SOMS) Na2Nb2O6-H2O:
   Synthesis, structure and thermodynamic stability
CHEMISTRY OF MATERIALS 16, 2004, 2034-2040.
A new microporous phase Na2Nb2O6.H2O, which transforms to NaNbO3
   perovskite on heating, has been synthesized by the hydrothermal method.
   Rietveld analysis of powder synchrotron X-ray diffraction data reveals
   that the structure comprises a framework of [NbO6] and [NaO6] pctahedra
   with other Na+ being located in the channels (space group C2/c; a =
   17.0511(9) Angstrom; b = 5.0293(2) Angstrom; c = 16.4921(9) Angstrom;
   beta =113.942(2)degrees). This phase belongs to the recently
   synthesized Sandia octahedral molecular sieves (SOMS) family,
   Na2Nb2-xMxO6-x(OH)(x).H2O (M = Ti, Zr) and is the archetype for the
   substituted structures. Using drop-solution calorimetry into molten
   3Na(2)O.4MoO(3) at 974 K, the enthalpies of formation of Na2Nb2O6.H2O
   from the constituent oxides and from the elements have been determined
   to be -295.4 +/- 4.8 and -2895.5 +/- 6.4 kJ/mol, respectively. From the
   drop-solution calorimetric data for Na2Nb2O6.H2O and its dehydrated
   perovskite phase, the enthalpy of the dehydration reaction,
   Na2Nb2O6.H2O --> 2NaNbO(3) + H2O, has been derived, and its
   implications for phase stability are discussed.


Christensen, M   Iversen, BB   Bertini, L   Gatti, C   Toprak, M
   Muhammed, M   Nishibori, E
Structural study of Fe doped and Ni substituted thermoelectric
   skutterudites by combined synchrotron and neutron powder diffraction
   and ab initio theory
JOURNAL OF APPLIED PHYSICS 96, 2004, 3148-3157.
We present neutron and synchrotron powder-diffraction investigations as
   well as ab initio calculations to elucidate delicate structural
   features in doped skutterudites. Samples with assumed Fe doping were
   investigated (FeyCo4Sb12, y=0.4, 0.8, 1.0, and 1.6), as well as samples
   with formal Ni substitution (Co4-xNixSb12, x=0, 0.4, 0.8, and 1.2). The
   present study serves as a case story for the determination of fine
   structural details of thermoelectric skutterudites by diffraction
   methods in combination with ab initio calculations. We illustrate the
   problem of fluorescence in the conventional x-ray powder diffraction on
   the Fe-doped samples by a comparison with the neutron
   powder-diffraction data. On the series of the Ni-substituted samples,
   the neutron powder-diffraction data were collected to investigate the
   exact sitting of the Ni. The sample with the highest Ni substitution
   (Co2.8Ni1.2Sb12) was also used for high resolution, high-energy
   synchrotron powder diffraction measurements. These revealed that the
   sample consists of two skutterudite phases. A complete description of
   the Ni-substituted samples was obtained in tandem with ab initio
   calculations, which show that the system contains a Ni-rich
   (Co0.38Ni3.62Sb12) and a Ni-poor (Co3.76Ni0.24Sb12)) skutterudite


Cernak, J   Gerard, F   Kappenstein, C   Chomic, J
Copper/Zinc oxide catalysts. Part XII. Solid solution formation in the
   CuO/ZnO system. X-ray powder diffraction study
MONATSHEFTE FUR CHEMIE 135, 2004; 1081-1088.
Coordination compounds Zn(ma1)(H2O)(2) (ZMH) (mal=maleate anion
   (C2H2(CO2)(2)(2-))), Cu0.06Zn0.94(mal)(H2O)(2) (ZCMH), Cu(mal)(H2O)
   (CMH), and physical mixtures of CMH and ZMH were used as precursors for
   calcination experiments in air at 500 and 1000degreesC lasting 18
   hours. The obtained oxides were investigated by X-ray powder
   diffraction technique. Calcination at 500degreesC yielded pure zincite
   phase (ZnO), tenorite phase (CuO), or their mixtures. The calcination
   of the Zn-rich sample ZCMH at 1000degreesC lead to zincite phase
   displaying a slightly lower cell volume than the pure zincite phase
   obtained from Zn-only containing precursor (ZMH). These results suggest
   that the assumed solid solution CuxZn1-xO (x=0.01-0.02) exhibits a
   solubility limit lower than the copper content in the ZCMH precursor (6
   mol-%). On the other hand, the calcination of the Cu-rich samples at
   1000degreesC, in the presence of Zn(II), yielded tenorite phase
   exhibiting cell parameters significantly different from those reported
   for the pure tenorite phase, due to the formation of Zn0.03Cu0.97O
   solid solutions. All these results are corroborated by intensity
   analysis of the diffraction peaks.


Pfeffer-Hennig, S   Piechon, P   Bellus, M   Goldbronn, C   Tedesco, E
Physico-chemical characterization of an active pharmaceutical
   ingredient - Crystal polymorphism and structural analysis
The physico-chemical properties and polymorphism of a new active
   pharmaceutical ingredient entity has been analyzed and the gain of
   knowledge during the chemical development of the substance is
   described. Initial crystallization revealed an anhydrous crystal form
   with good crystallinity and a single, sharp DSC melting peak at 171
   degreesC and a straightforward development of this crystal form seemed
   possible. However, during polymorphism screening, new crystalline forms
   were detected that were often analyzed as mixtures of crystal forms.
   The process of characterization and identification of the different
   crystalline forms and its thermodynamical relationship has been
   supported by a combination of experimental and computational work
   including determination of the three-dimensional structures of the
   crystal forms. The crystal structure of one polymorphic form was solved
   by single crystal X-ray structure analysis. Unfortunately, Mod B
   resisted in formation of suitable single crystals, but its structure
   could be solved by high resolution powder diffraction data analysis
   using synchrotron radiation. Calculation of the theoretical X-ray
   powder diffraction pattern from three dimensional crystal coordinates
   allowed an unambiguous identification of the different crystalline
   forms. Two polymorphic crystal forms of the API-CG3, named Mod A and
   Mod B, are enantiotropic whereas Mod B is the most stable polymorph at
   room temperature up to about 50 degreesC and Mod A at temperatures
   above 50 degreesC. The mechanism of the solid - solid transition can be
   explained by analyzing the molecular packing information gained from
   the single crystal structures. A third crystalline form with the
   highest melting peak turned out to be not a polymorphic or
   pseudopolymorphic crystal modification of our API-CG3 but a chemically
   different substance.

Schobinger-Papamantellos, P   Rodriguez-Carvajal, J   Andre, G
   Ritter, C   Buschow, KHJ
Re-entrant magneto-elastic transition in HoFe4Ge2 a neutron diffraction
The re-entrant magneto-elastic transition of the antiferromagnetic
   HoFe4Ge2 compound has been studied by neutron powder diffraction as a
   function of temperature. The magnetic phase diagram comprises the wave
   vectors: (q(1o), q(2o), q(1t)) and three magnetic transitions, two of
   them occurring simultaneously with the structural changes at T-c, T-N =
   52 and T-c', T-ic1 = 15 K, the third being purely magnetic at T-ic2 =
   40 K. The first transition is of second order while the latter two of
   first order. The sequence of phases follows the path: P4(2)/mnm (HT),
   T-c, T-N = 52 K --> Cmmm (IT): (q(1o) = (0, 1/2, 0) T-ic2 = 40 K double
   right arrow q(2o) = (0, q(y), 0)), T-c', T-ic1 = 15 K double right
   arrow P4(2)/mnm (LT): q(1t) = (0, 1/2, 0). The magnetic structures
   described by the wave vectors (q(1o), q(2o) and q(1t)), where the
   components are referred to the reciprocal basis of the conventional
   Cmmm cell, correspond to canted multi-axial arrangements. The q(2o)
   wave vector length of the amplitude modulated phase varies
   non-monotonously, decreasing fast just below T-ic2,-slowly between
   36K-T-c', T-ic1 and jumping to the q(1t) = (0, 1/2,0) lock-in value at
   T-c', T-ic1 simultaneously with the first order re-entrant transition
   to the (LT) tetragonal phase. In the coexisting meta-stable
   orthorhombic phase from T-c', T-ic1 down to 1.5 K the length of the
   wave vector q(2o) continues to decrease. To solve the magnetic
   structures of all the phases appearing in this complex situation,
   arising from competing ordering mechanisms and anisotropies of the
   underlying sublattices, we have used the simulated annealing method of
   global optimisation on high-resolution neutron powder diffraction data.


Pirozzi, B   Napolitano, R   Petraccone, V   Esposito, S
Determination of the crystal structure of syndiotactic
   3,4-poly(2-methyl-1,3-butadiene) by molecular mechanics and X-ray
The crystal structure of syndiotactic 3,4-poly(2-methyl-1,3-butadiene)
   has been determined by the joint use of molecular mechanics and X-ray
   diffraction. Molecular mechanics calculations have been performed both
   on the isolated chain and on the crystal by the use of various force
   fields. The energy minimizations predict a model of the crystal
   structure. The calculated X-ray powder diffraction pattern is in good
   agreement with the experiment one. This model had been refined in order
   to obtain the best agreement with all the experimental data. The space
   group id Pbcm and the parameters of the unit cell are a = 6.6 Angstrom,
   b = 13.2 Angstrom, c = 5.27 Angstrom. The presence of defects in the
   crystal has been taken into account. Analogies and differences with the
   crystal structure of syndiotactic 1,2-poly(1,3-butadiene) are discussed.


Weirich, TE
The crystal structure of Zr2Se reinvestigated by electron
   crystallography and X-ray powder diffraction
The metal-rich compound Zr2Se is of particular interest for electron
   crystallography, since it was one of the first examples that proved
   that heavy-atom structures can be solved via quasi-automatic direct
   methods from selected area electron diffraction intensities [1]. For
   this reason, Zr2Se has been chosen as a model to discuss the
   possibilities and the limits of the quasi-kinematical approach that has
   been successfully used to determine this and related structures from
   high-resolution electron microscopy (HREM) images and selected area
   electron diffraction. In order to quantify the achievable accuracy of
   the electron crystallography techniques used, the corresponding
   structures are compared with results from structural analysis with
   X-ray powder data and with a model received from first-principles
   calculations. The latter structure was chosen in this study as a
   reference, since the calculations do not depend on experimental
   parameters. Analysis of the obtained result from electron diffraction
   structural analysis (EDSA) shows that the structural model is, on
   average, only off by 0.08 Angstrom, despite the investigated crystal
   having an effective thickness of 286 Angstrom. The corresponding result
   from Rietveld refinement with X-ray powder data agrees to within 0.04
   Angstrom with the structure from calculation and within 0.03 Angstrom
   with the result from an earlier single crystal X-ray study [2].


Rius, J   Elkaim, E   Torrelles, X
Structure determination of the blue mineral pigment aerinite from
   synchrotron powder diffraction data: The solution of an old riddle
The structure of aerinite, a blue fibrous silicate mineral associated
   with the alteration of ophitic rocks in the southern Pyrenees, has been
   determined by applying the direct methods modulus sum function to
   synchrotron powder diffraction data. This mineral was the blue pigment
   commonly used in most Catalan romanic paintings between the XI-XV
   centuries. The studied specimen comes from the Camporrells-Estopanya
   area (Huesca, Spain). The unit cell dimensions are a = b = 16.8820(9),
   c = 5.2251(3) Angstrom, the space group is P3c1 and the structural
   formula is (Ca5.1Na0.5)(Fe3+AlFe2+ Mg-1.7(0.3))(Al5.1Mg0.7)
   [Si12O36(OH)(12)H].[(CO3)(1.2)(H2O)(12)] With Z = 1 and D-c = 2.52
   g/cm(3) (Fe2+/Fe3+ ratio from Mossbauer spectroscopy; carbonate content
   confirmed by infrared spectroscopy). The model of the structure
   obtained by direct methods was refined with the Rietveld method to the
   residual value R-wp = 0.0937 (chi(2) = 1.05). A bond valence analysis
   shows the plausibility of the refined model.
   The crystal structure of aerinite can be best understood by introducing
   cylindrical basic building units consisting on three pyroxene chains
   pointing inwards to accommodate tri- and divalent metal cations at the
   centres of the resulting face-sharing octahedra. The average
   composition of these cationic sites is Fe3+ (0.25),Al3+ (0.25),Fe2+
   (0.43),Mg2+ (0.07), the mean cation-oxygen bond length is 2.054(9)
   Angstrom and the intercationic distance is 2.61 Angstrom. Out of the
   three symmetry-independent three-fold rotation axes in the unit cell,
   two are occupied by such cylindrical units and the third by CO3 groups.
   Consequently, each unit is surrounded by three similar ones which are,
   however, shifted by 0.93 Angstrom along c. Between two such units,
   i.e., tangential to both cylindrical envelopes, a four-row wide slab of
   a brucite-like layer is found. The two inner octahedra are
   predominantly filled with Al and Mg atoms, the two outer with Ca, Na
   and some vacancies [average values: d(Al-O) = 1.936(53) Angstrom (6x),
   angle(O-Al-O) = 90.1(6.5)degrees (12x) and 172.7(4.1)degrees (3x);
   d(Ca-O) = 2.42(6) Angstrom (6x), angle(O-Ca-O) = 90(23)degrees (12x)
   and 158(14)degrees (3x)]. The internal O atoms of the brucite-like
   layer are hydroxyl groups, the intermediate are unshared basal O atoms
   of the neighbouring pyroxene chains, while the external ones are water
   molecules forming relatively strong H-bridges with the partially
   disordered CO3 groups. Presumably, the hydroxyl groups in the
   brucite-like layer also form H-bridges with the apical O atoms of the
   neighbouring pyroxene chains to compensate for the defect of charge
   caused by the presence of divalent cations in the face-sharing


Sainz-Diaz, CI   Villacampa, A   Otalora, F
Crystallographic properties of the calcium phosphate mineral, brushite,
   by means of First Principles calculations
AMERICAN MINERALOGIST 89, 2004, 307-313?
A crystalline form of hydrated calcium phosphate, brushite
   (CaHPO(4)(.)2H(2)O), has been studied by means of total energy First
   Principles calculations based on the Density Functional Theory (DFT)
   approximation. The experimental crystal lattice parameters of this
   mineral have been reproduced with good agreement. The powder X-ray
   diffraction pattern simulated from the calculated crystal structure is
   similar to the experimental one. The intermolecular interactions within
   the crystal, electrostatic and hydrogen bond interactions, have been
   reproduced. The calculated crystal structure reproduces the atomic
   distribution along the (010) surface observed by high resolution
   scanning force microscope (SFM). The optimized crystal structure
   describes the different interatomic interactions along the [101],
   [201], and [001] directions on the (010) plane. Quantum-mechanical
   calculations of the energy of these surfaces confirm the experimental
   behavior, justifying the different crystal growth rates of these
   directions found experimentally.


Du, HL   Han, JZ   Zhang, WY   Wang, CS   Wang, WC   Liu, SQ
   Chen, HY   Zhang, XD   Yang, YC
Determination of the zirconium site in zirconium-substituted
   Nd(Fe,Mo,Zr)(12) compounds
The NdFe10.5Mo1.5-xZrx (x = 0.25,0.50) and Nd0.5Pr0.5Fe10.5-xMo1.5Zrx
   (x = 0, 0.25, 0.75, and 1.00) intermetallic compounds with ThMn12-type
   structures were successfully synthesized. Their structures were
   investigated by using powder X-ray diffraction. It is found that Zr is
   incorporated as a substituent for Nd/Pr in the structure of the two
   series, and the occupation of Zr is influenced by the prepared
   composition of Fe and the third element Mo. The effects of Zr on the
   magnetic properties were also studied.


Breza, M   Biskupic, S
On the structure of tetralead(II) complexes with OH bridges
Using Hartree-Fock, B3LYP and MP2 treatments, the optimal geometries
   and corresponding electronic structures of tetrahedral
   [Pb-4(mu(3)-OH)(n)](q) and [Pb4O(mu(3)-OH)(n)](q-2) complex cations
   with total charges q = 8 - n, n = 2, 3, 4, are investigated. After OH-
   removal, the central oxygen atom in [Pb4O(mu(3)-OH)(4)](2+) is shifted
   to the apical position in [Pb4O(mu(3)- OH)(3)](3+) whereas the
   [Pb-4(mu(3)-OH)(2)](6+) and [Pb4O(mu(3)-OH)(2)](4+) complex cations are
   unstable. Direct Pb-Pb and O-O interactions are weakly antibonding in
   all the systems under study. The clusters are held together exclusively
   by relatively weak Pb-O bonds. A higher stability of the complex
   cations with a larger number of OH- bridges may be confirmed.


Breza, M   Biskupic, S
On the structure of boat-shaped hexalead(II) cations with OH bridges
Using Hartree - Fock, B3LYP, and MP2 treatments, the optimal
   boat-shaped geometries and corresponding electronic structures of
   [Pb6Om(mu(3)-OH)(n)](q) complex cations with total charges q = 12 - 2m
   - n, m = 0 or 1, n = 6 or 8, are investigated. Whereas the
   [Pb-6(mu(3)-OH)(6)](6+) cation is unstable, the remaining structures
   preserve C-2v symmetry. Direct Pb - Pb interactions are weakly
   antibonding in all the systems under study. The clusters are held
   together exclusively by relatively weak Pb - O bonds. The effects of
   central O and two additional mu(3)-OH bridges in
   [Pb6O(mu(3)-OH)(8)](2+) are not fully cooperative.
   [Pb6O(mu(3)-OH)(6)](4+) and [Pb-6(mu(3)-OH)(8)](4+) may coexist in
   water solutions in comparable concentrations.


Laco, JII
Crystal structures of poly(n-methylen-di-O-methyl-L-tartaramide)s with
   n=3, 5, 7 and 9
POLYMER 45, 2004, 7025-7033
The structural characterization of
   poly(n-methylen-di-O-methyl-L-tartaramide)s with n = 3, 5, 7 and 9 has
   been carried out using optical microscopy, thermal analysis, X-ray
   diffraction and electron microscopy. X-ray diffraction of powder and
   fiber samples were analyzed together with electron diffraction patterns
   of single crystals obtained from isothermal crystallization in
   solution. Experimental results based on crystallographic data were used
   to build a crystal model using the Cerius program. This model is based
   in chain packing with an arrangement of hydrogen-bonded sheets, being
   the resultant crystal structure similar to the exhibited in
   conventional polyamides.


Abakumov, AM   Rozova, MG   Chizhov, PS   Antipov, EV   Hadermann, J   Van Tendeloo, G
Synthesis and crystal structure of the novel Pb5Sb2MnO11 compound
The new Pb5Sb2MnO11 compound was synthesized using a solid-state
   reaction in an evacuated sealed silica tube at 650degreesC. The crystal
   structure was determined ab initio using a combination of X-ray powder
   diffraction, electron diffraction and high-resolution electron
   microscopy (a = 9.0660(8) Angstrom, b = 11.489(1) Angstrom, c =
   10.9426(9) Angstrom, S.G. Cmcm, R-1 = 0.045, R-P = 0.059). The
   Pb5Sb2MnO11 crystal structure represents a new structure type and it
   can be considered as quasi-one-dimensional, built up of chains running
   along the c-axis and consisting of alternating Mn+2O7 capped trigonal
   prisms and Sb2O10 pairs of edge sharing Sb+5O6 octahedra. The chains
   are joined together by Pb atoms located between the chains. The Pb+2
   cations have virtually identical coordination environments with a clear
   influence of the lone electron pair occupying one vertex of the PbO5E
   octahedra. Electronic structure calculations and electron localization
   function distribution analysis were performed to define the nature of
   the structural peculiarities. Pb5Sb2MnO11 exhibits paramagnetic
   behavior down to T = 5K with Weiss constant being nearly equal to zero
   that implies lack of cooperative magnetic interactions.


Brize, V   Georges, S   Kodjikian, S   Suard, E   Goutenoire, F
La6Mo8O33: a new ordered defect Scheelite superstructure
The structure of La6Mo8O33 has been determined from a triple pattern
   powder diffraction analysis. Two high-resolution neutron diffraction
   patterns collected at 1.594 and 2.398 Angstrom and one X-rays were
   used. This molybdate crystallizes in a non-centrosymmetric monoclinic
   space group P2(1) (Ndegrees4), Z = 2, a = 10.7411(3) Angstrom, b =
   11.9678(3) Angstrom, c = 11.7722(3) Angstrom, beta = 116.062
   (1)degrees. La6Mo8O33 is an unusual ordered defect Scheelite. Hence, it
   should be described with cation vacancies and an extra oxygen atom
   following the formula: La(6)rectangle(2)Mo(8)O(32+1). This extra oxygen
   atom leads to a pyramidal environment, whereas the other molybdenum
   atoms present tetrahedral environment. A molybdenum tetrahedral is
   connecting to the pyramid, forming an [Mo2O9] unit.


Kamegashira, N   Satoh, H   Meng, J   Mikami, T
Structural determination of a new phase of monoclinic BaTb2Mn2O7
A new phase of monoclinic BaTb2Mn2O7 with extra superlattice lines in
   addition to the usual orthorhombic X-ray diffraction patterns was
   prepared and a Rietveld refinement was applied to analyze the crystal
   structure using X-ray powder diffraction data at room temperature. The
   refined lattice parameters were a = 0.54918(8) nm, b = 2.0149(5) nm, c
   = 0.54922(9) nm, and beta = 90.62degrees with the space group A2/m (no.
   12). The MnO6 oxygen octahedron has distortion and tilts around a-axis
   by about 7degrees each other in the reverse direction.


Perchiazzi, N   Gualtieri, AF   Merlino, S   Kampf, AR
The atomic structure of bakerite and its relationship to datolite
AMERICAN MINERALOGIST 89, 2004, 767-776.
Four samples of bakerite, Ca4B5Si3O15(OH)(5), were studied by means of
   IR, TG/DSC, EPMA, and X-ray and neutron diffraction. Chemical analyses
   can readily discriminate bakerite from datolite, Ca4B4Si4O16(OH)(4), by
   the distinctly lower SiO2 content of the former. The Rietveld
   refinement of the combined neutron and X-ray powder data allow the
   determination of the crystal structure of bakerite to R-p 3.09%. The
   crystal structure can be derived from that of datolite by the
   substitution 0.25Si(4+) + 0.25O(2-) <----> 0.25B(3+) + 0.25(OH)(-) at
   the Si-centered tetrahedral site. This leads to the crystal chemical
   formula Ca(4)B(5)Si(3)0O(15)(OH)(5). Both of the two hydrogen positions
   in the bakerite structure, one with full occupancy, the other with 25%
   occupancy, were precisely located. The water molecule generally thought
   to be present in bakerite structure is actually absent. The excess
   water detected in chemical analyses can be attributed to the presence
   of minor impurities. Given the consistent composition of bakerite from
   various localities and no evidence for Substitution of B for Si in
   datolite, bakerite is retained as a distinct species. A possible
   explanation of the peculiar 5:3 boron to silicon ratio in bakerite is


Patoux, S   Rousse, G   Leriche, JB   Masquelier, C
Crystal structure and lithium insertion properties of orthorhombic
   Li2TiFe(PO4)(3) and Li2TiCr(PO4)(3)
SOLID STATE SCIENCES 6, 2004, 1113-1120.
The crystal structures of orthorhombic Li2TiFe(PO4)(3) and
   Li2TiCr(PO4)(3) were determined from Rietveld refinement of neutron
   powder diffraction data. Both compounds are isostructural in the Pbna
   space group with a = 8.543(1) Angstrom, b = 8.623(1) Angstrom, c =
   11.978(1) Angstrom and a = 8.505(1) Angstrom, b = 8.589(1) Angstrom, c
   = 11.929(1) Angstrom, respectively. Lithium ions are located in a
   single four-fold coordinated site Li(1). Electrochemical insertion of
   lithium proceeds through the reduction of Fe3+ into Fe2+ (similar to
   2.8 V vs. Li+/Li) and Ti4+ into Ti3+ (similar to 2.5 V vs. Li+/Li)
   towards the new compositions Li3TiCr(PO4)(3) and Li4TiFe(PO4)(3). In
   situ X-ray diffraction and potentiostatic intermittent titration
   technique indicate a solid solution mechanism for the reversible
   lithium insertion/extraction. Chemical reaction of Li2TiFe(PO4)3 with
   n-BuLi leads to orthorhombic Li4TiFe(PO4)3.


Wallez, G   Launay, S   Quarton, M   Dacheux, N   Soubeyroux, JL
Why does uranium oxide phosphate contract on heating?
(U2O)(PO4)(2) is related to ultra-low expansion beta-(Zr2O)(PO4)(2)
   ceramics, but shows a continuous thermal contraction. High-temperature
   neutron diffraction has allowed to follow accurately the thermal
   variations of its cell edges and to give a structural explanation to
   the phenomenon: like in beta-(Zr2O)(PO4)(2), the dilatometric anomaly
   arises simultaneously from a contractive push-pull effect due to
   Coulombic repulsions and from a libration of the PO4 and UO7 polyhedra,
   but in the present case, the second mechanism predominates. The size of
   the tetravalent cation appears as a key parameter in monitoring the
   thermal expansion of ceramics of this family.


Yan, W   Lerner, MM
Synthesis and structural investigation of new graphite intercalation
   compounds containing the perfluoroalkylsulfonate anions C10F21SO3-,
   C2F5OC2F4SO3-, and C2F5(C6F10)SO3-
CARBON 42, 2004, 2981-2987.
The preparation of graphite intercalation compounds (GIC's) of three
   perfluorinated alkylsulfonate anions, C10F21SO3-, C2F5OC2F4SO3- and
   C2F5(C6F10)SO3- is described for the first time. Pure stage 2 GIC's are
   obtained by chemical oxidation of graphite with K2MnF6 in a solution
   containing hydrofluoric and nitric acids for 72 h. One-dimensional
   electron density maps derived from powder diffraction data are fit to
   obtain models for the intercalate gallery structures: the structure
   models provide details on anion concentrations, orientations, and
   conformations. In all cases, anion bilayers are observed with anion
   sulfonate headgroups oriented towards graphene sheets. Compared with
   structures calculated for the isolated anions, the intercalated anion
   conformations show changes in dihedral angles, involving rotations
   about C-C or C-O bonds. For the GIC containing C2F5(C6F10)SO3-, the
   anion conformation change is related to the more efficient packing of
   anions in the intercalate gallery.


Tremayne, M
Direct space structure solution applications
   TECHNOLOGY 109, 2004, 49-63.
The crystal structures of 2,4,6-triisopropyl-benzenesulfonamide,
   1,2,3-trihydroxybenzenehexamethylenetetramine (1/1), 5-bromonicotinic
   acid and chlorothalonil form II have been solved from x-ray powder
   diffraction data, by application of a direct space structure solution
   approach using the Monte Carlo method and confirmed by Rietveld
   refinement. In the sulfonamide, the molecules are linked by N - H...O
   hydrogen bonds into two-dimensional sheets built from alternating eight
   and twenty-membered rings. In the cocrystal, the molecules are linked
   by O-H...N hydrogen bonds to form puckered molecular ribbons that are
   in turn linked into a continuous 3D framework by C-H...pi ( arene)
   interactions. 5-bromonicotinic acid also displays atypical
   hydrogen-bonding behaviour by formation of dimers through a
   self-complementary acid-acid hydrogen-bond motif that are connected
   into antiparallel ribbons by C - H...O and C - H...N hydrogen bonds.
   Structure determination of the cocrystal and the bromonicotinic acid
   was successful despite the presence of preferred orientation in the
   data, whereas the distortion of the chlorothalonil data was so severe
   that structure solution was only possible when the effects of preferred
   orientation were minimized. Both the disordered structure, and an
   ordered structural approximation of chlorothalonil form II have been
   determined and rationalized.

2004-158  ???

Siwicka, A   Reiter, RJ   Tian, DX   Wojtasiewicz, K   Leniewski, A
   Maurin, JK   Blachut, D   Czarnocki, Z
The synthesis and the structure elucidation of N,O-diacetyl derivative
   of cyclic 3-hydroxymelatonin
Melatonin was subjected to an oxidation to give 3-hydroxymelatonin. All
   spectroscopic data for this compound were collected. Ab initio
   calculations for both possible configurations were performed. X-ray
   data on N, O-diacetyl derivative of 3-hydroxymelatonin allowed the
   unambigous structure determination.


Muhle, C   Karpov, A   Nuss, J   Jansen, M
Crystal growth and crystal structure determination of
   K-2[Pt(CN)(4)Cl-2], K-2[Pt(CN)(4)Br-2], K-2[Pt(CN)(4)I-2] and
   K-2[Pt(CN)(4)]Cl-2] .  2H(2)O
 Crystals of K2Pt(CN)(4)Br-2, K2Pt(CN)(4)I-2 and
   K2Pt(CN)(4)Cl(2)(.)2H(2)O were grown, and their crystal structures have
   been determined from single crystal data. The structure of
   K2Pt(CN)(4)Cl-2 has been determined and refined from X-ray powder data.
   All compounds crystallize monoclinicly (P2(1)/c; Z = 2), and
   K2Pt(CN)(4)X-2 with X = Cl, Br, I are isostructural. K2Pt(CN)(4)Cl-2: a
   = 708.48(2); b = 903.28(3); c = 853.13(3) pm; beta = 106.370(2)degrees;
   R-p = 0.064 (N(hkl) = 423). K2Pt(CN)(4)Br-2: a = 716.0(1); b =
   899.1(1); c = 867.9(1) pm; beta = 106.85(1)degrees; R(F)(N') = 0.026
   (N'(hkl) = 3757). K2Pt(CN)(4)I-2: a = 724.8(1); b = 914.5(1); c =
   892.1(1) pm; beta = 107.56(1)degrees; R(F)(N') = 0.025 (N'(hkl) =
   2197). K2Pt(CN)(4)Cl-2 (.) 2H(2)O: a = 763.76(4); b = 1143.05(6); c =
   789.06(4) pm; beta = 105.18(1)degrees; R(F)(N') = 0.021 (N'(hkl) =
   2281). Raman and infrared spectroscopy data are reported.


Niewa, R   Zherebtsov, DA
New phases in the lithiumnitridovanadate system - The solid solution
   Li7-2xMgx[VN4] with 0 <= x <= 1
Solid solution phases Li7-2xMgx[VN4] (0 < x less than or equal to 1)
   with varying Mg-content are obtained as yellow microcrystalline powders
   from heat treatment of mixtures of VN, Li3N and Mg3N2 or from mixtures
   of Li-7[VN4] and Mg3N2 at 1370 K in N-2 atmosphere at ambient pressure.
   At substitution parameter values of x > 0.5 a subsequent distortion
   from the ideal cubic unit cell to an orthorhombic unit cell is
   observed. The crystal structure of Li7-2xMgx[VN4] with x approximate to
   1 was refined from neutron and X-ray powder diffraction data (space
   group Pbca, No. 61, a = 963.03(3) pm, b = 958.44(3) pm, c = 951.93(2)
   pm, neutron pattern 14degrees - 156degrees 2theta, step non-linear
   approximate to 0.0782degrees 2theta, No. of measured points 1816, R-p =
   0.089, R-wp = 0.115, R-Bragg = 0.155, R-F = 0.114; X-ray pattern
   10degrees - 98degrees 2theta, step 0.005degrees 2theta, No. of measured
   points 17600, R-p = 0.028, R-wp = 0.045, R-Bragg = 0.113, R-F = 0.133,
   structure variables: 45). The crystal structure resembles a Li2O type
   superstructure with the atomic arrangement of beta-Li-7[VN4] and with
   two crystallographic Li-sites each substituted by Mg with statistical
   occupation factors of 0.5. Chemical analyses prove the composition and
   XAS spectroscopy at the V K-edge support the +5 oxidation state
   assignment for vanadium. XAS data also support the tetrahedral
   coordination of vanadium by N as indicated by the structure refinements.


Le Berre, F   Crosnier-Lopez, MP   Fourquet, JL
Cationic ordering in the new layered perovskite BaSrTa2O7
SOLID STATE SCIENCES 6, 2004, 53-59.
BaSrTa2O7 is a new well-ordered layered perovskite synthesized by solid
   state reaction. This phase derives from the Dion-Jacobson family of
   general formula A'[A(n-1)B(n)O(3n+1)] with B =Ta and n =2 in which the
   monovalent cation A' is replaced by one divalent cation. The structure
   was refined from X-ray powder diffraction data in the orthorhombic
   space group Immm (No. 71) with lattice constants a = 3.99372(5)
   Angstrom, b = 7.8428(1) Angstrom and c = 20.1609(3) Angstrom (Z = 4).
   Although the similar Sr-O and Ba-O distances allow the localization
   inside or between the perovskite blocks for the two cations, the X-ray
   study reveals that the Ba2+ and Sr2+ ions are strictly ordered: Ba2+
   ions in an interlayer position (4j site) and Sr2+ ions within the
   perovskite blocks (2b and 2c sites). TEM study is undertaken to verify
   the local Ba2+/Sr2+ distribution (local ordering or population
   fluctuations) and to check the possible existence of other n members.


Ferey, G   Serre, C   Mellot-Draznieks, C   Millange, F
   Surble, S   Dutour, J   Margiolaki, I
A hybrid solid with giant pores prepared by a combination of targeted
   chemistry, simulation, and powder diffraction


Brodski, V   Peschar, R   Schenk, H   Brinkmann, A   van Eck, ERH
   Kentgens, APM   Coussens, B   Braam, A
Structure of melaminium dihydrogenpyrophosphate and its formation from
   melaminium dihydrogenphosphate studied with powder diffraction data,
   solid-state NMR, and theoretical calculations
JOURNAL OF PHYSICAL CHEMISTRY B 108, 2004, 15069-15076.
Melaminium dihydrogenpyrophosphate (bis(2,4,6-triamino-1,3,5-triazinium
   dihydrogenpyrophosphate, MPy), obtained as a crystalline powder by
   thermal treatment of melaminium dihydrogenphosphate (MP), is the first
   intermediate in the synthesis of polymerized melamine phosphates that
   are used as environmental-friendly flame retardants. The crystal
   structure of MPy was determined by X-ray powder diffraction and the
   proposed hydrogen-bonding model was corroborated by solid-state NMR and
   periodic DFT calculations. A mechanism is proposed for the endothermic
   dehydration process that takes place in the reaction from MP to MPy, in
   accordance with energy calculations based on the optimized crystal
   structures of MPy and MP. A packing analysis of MPy and other
   melamine-containing compounds revealed some typical melamine packing


Schenk, H   Peschar, R
Understanding the structure of chocolate
Crystallization of cocoa-butter in the beta phase from the melt under
   static conditions is only possible using the memory effect of
   cocoa-butter. Under all other conditions polymorphs with lower melting
   temperatures develop, whereas the beta phase is the preferred one in
   chocolate. SAXS experiments proved 1,3-distearoyl-2-oleoylglycerol
   seeds with triple chain-length packing initiate the
   beta-crystallization. Models for the different phases may be based on
   the crystal structure determinations of triacylglycerols.
   A new, patented, way of chocolate making is in development in which the
   traditional tempering process is replaced by another
   pre-crystallization process. The process is based on the use of seed
   crystals in the liquid phase and driven by a feedback system.


De Ridder, DJA   Goubitz, K   Brodski, V   Peschar, R   Schenk, H
Crystal structure of melaminium orthophosphate from high-resolution
   synchrotron powder-diffraction data
HELVETICA CHIMICA ACTA 87, 2004, 1894-1905.
The crystal structure of melaminium orthophosphate (MP) has been
   determined from high-resolution synchrotron powder-diffraction data.
   The crystal packing consists of melaminium layers and pairs of
   orthophosphate chains connected by H-bonds almost perpendicular to the
   layers. The distance between melaminium layers is 3.62 Angstrom.
   Neighboring melaminium molecules do not lie in the same plane, but in
   two parallel planes at close distance (0.79 Angstrom), and are shifted
   with respect to each other. The orthophosphate chains are connected by
   both intra-chain and inter-chain H-bonds. The melamine is singly
   protonated at an endocyclic N-atom. The powder-diffraction data were
   corroborated by solid-state NMR experiments.


Vos, TE   Liao, Y   Shum, WW   Her, JH   Stephens, PW   Reiff, WM   Miller, JS
Diruthenium tetraacetate monocation, [Ru-II/(III)(2)(O2CMe)(4)](+),
   building blocks for 3-D molecule-based magnets
Diruthenium tetracarboxylates monocations are utilized as building
   blocks for cubic 3-D network structured molecule-based magnets.
   [Ru-2(II/III)(O2CMe)(4)](3)[M-III(CN)(6)] [M = Cr (1a), Fe (2), Co (3)]
   were prepared in aqueous solution. Powder X-ray diffraction indicates
   that they have body-centered cubic structures (space group = lm (3)
   over barm, a = 13.34, 13.30, and 13.10 Angstrom for 1a, 2, and 3,
   respectively), which was confirmed for 1a by Reitveld analysis of the
   synchrotron powder data [a = 13.3756(5) Angstrom].
   [Ru-2(O2CMe)(4)](3)[M-III(CN)(6)](.)xMeCN [M = Cr, x = 1.8 (1b); M =
   Mn, x = 3.3 (4)] were prepared from acetonitrile. The magnetic ordering
   of 1a (33 K), 1b (34.5 K), 2 (2.1 K), and 4 (9.6 K) was determined from
   the temperature dependencies of the in-phase (chi') alternating current
   (AC) susceptibility. The field dependence of the magnetization, M(H),
   at 2 K for 1a showed an unusual constricted hysteresis loop with a
   coercive field, H-cr, of 470 Oe while the 10(h) data for 1b, 2, and 4
   showed a normal hysteresis loop with a coercive field of 1670, 10, and
   990 Oe, respectively. The Fe-57 Mossbauer spectrum of 2 is consistent
   with the presence of low spin Fe-III (6 = -0.05 mm/s; DeltaE = 0.33
   mm/s) at room temperature, and the onset of 3-D magnetic ordering at
   lower temperature (<2 K). The effects of M-III in [M-III(CN)(6)](3-),
   and the large zero-field splitting (D) of diruthenium tetracarboxylates
   are discussed. The increasing critical temperatures T-c, with
   increasing S could not be accounted for by mean field models without
   significantly different J values for 1a, 4, and 2. By fitting the T-c
   data with mean field models [H = -2JS(Ru)(.)S(M) - mu(B)(g(Ru)S(Ru) +
   g(M)S(M))(H)], J/k(B) are 4.46, 1.90, and 0.70 K for 1a, 4, and 2,


Mazina, OS   Rybakov, VB   Chernyshev, VV   Babaev, EV   Aslanov, LA
X-ray mapping in heterocyclic design: XIV. Tricyclic heterocycles based
   on 2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile
The structures of four compounds are studied using single-crystal X-ray
   -carbonitrile [a = 4.908(4) Angstrom, b = 11.644(10) Angstrom, c =
   13.587(2) Angstrom, beta = 94.31(5)degrees, Z = 2, space group P2(1)];
   trile [a = 7.6142(8) Angstrom, b = 14.778(2) Angstrom, c = 14.132(2)
   Angstrom, beta = 100.38(1)degrees, Z = 4, space group P2(1)/c];
   quinolin-3-ium perchlorate [a = 5.589(7) Angstrom, b = 24.724(15)
   Angstrom, c = 13.727(5) Angstrom, beta = 97.66(9)degrees, Z = 4, space
   group P2(1)/n]; and
   methanone [a = 7.150(2) Angstrom, b = 7.4288(10) Angstrom, c =
   15.314(3) Angstrom, alpha. = 98.030(10)degrees, 99.21(2)degrees, gamma
   = 105.34(2)degrees, Z = 2, space group P (1) over bar]. The structures
   are solved by direct methods and refined by the full-matrix
   least-squares procedure in the anisotropic approximation to R = 0.0728,
   0.0439, 0.1228., and 0.0541, respectively. The structure of
   oline-5-carboxamide [a = 23.9895(9) Angstrom, b = 5.1557(3) Angstrom, c
   = 17.0959(9) Angstrom, 0 = 106.43degrees, Z = 4, space group P-1/c] is
   investigated by X-ray powder diffraction. This structure is solved
   using the grid search procedure and refined by the Rietveld method to
   R-wp = 0.0773, R-exp= 0.0540, R-p = 0.0585, R-b = 0.1107, and chi(2) =


Al'bov, DV   Mazina, OS   Rybakov, VB   Babaev, EV   Chernyshev, VV   Astanov, LA
X-ray mapping in heterocyclic design: XII. X-ray diffraction study of
   2-pyridones containing cycloalkane fragments annelated to the C(5)-C(6)
The structures of 4,6-dimethyl-1H-pyridin-2-one [a = 6.125(2) Angstrom,
   b = 15.153(4) Angstrom, and c = 14.477(4) Angstrom, Z = 8, space group
   Pbca], the 2 : 1 : 1 complex of
   4-methyl-1,5,6,7-tetrahydro-2H-cyclopenta[b]pyridin-2-one with
   phosphoric acid and methanol [a = 11.181(2) Angstrom, b = 14.059'(6)
   Angstrom, c = 13.593(4) Angstrom, beta = 97.78(2)degrees, Z = 8, space
   group P2(1)/n],
   4-methyl-1,5,6,7,8,9-hexahydro-2H-cyclohepta[b]pyridin-2-one [a =
   12.565(6) Angstrom, b = 5.836(6) Angstrom, c = 13.007(3) Angstrom, beta
   = 93.10(3)degrees, Z = 4, space group P2(1)/n], and
   4-methyl-5,6,7,8,9,10-hexahydrocycloocta[b]pyridin-2(1H)-one [a =
   12.955(3) Angstrom, b = 6.1595(15) Angstrom, c = 13.038(3) Angstrom,
   beta = 95.50(2)degrees, Z= 4, space group P2(1)/n] are determined b
   single-crystal X-ray diffraction. The structures are solved by direct
   methods and refined by the full-matrix least-squares procedure in the
   anisotropic approximation to R = 0.0755, 0.0644, 0.0754, and 0.0569,
   respectively. The structures of 4-methyl-
   1,5,6,7-tetrahydro-2H-cyclopenta[b]pyridin-2-one [a = 7.353(4)
   Angstrom, h = 8.176(4) Angstrom, c = 13.00(1) Angstrom, beta =
   195.64(2)degrees, Z = 4, space group P2(1)/c] and
   2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile [a = 5.9870(2)
   Angstrom, b = 16.5280(5) Angstrom, c = 9.6540(3) Angstrom, beta =
   111.52(4)degrees, Z = 4, space group P2(1)/c] are studied by the powder
   diffraction technique. The structures are solved using the grid search
   procedure and refined by the Rietveld method to R-wp = 0. 108 and 0.058
   R-exp = 0.032 and 0.027, R-p = 0.076 and 0.043, R-b = 0. 123 and 0.077,
   and chi(2) = 7.9 and 3.64, respectively. In all the structures,
   hydrogen bonds involving the N, H, and 0 atoms of the pyridone fragment
   are formed.


Bouznik, VM   Kirik, SD   Solovyov, LA   Tsvetnikov, AK
A crystal structure of ultra-dispersed form of polytetrafluoroethylene
   based on X-ray powder diffraction data
POWDER DIFFRACTION, 19, 2004, 219-224.
An X-Ray powder diffraction study of ultra-dispersed
   polytetrafluoroethylene was carried out. As well as a regular
   polytetrafluoroethylene the ultra-dispersed form contents a high
   proportion of the crystalline phase. The X-ray diffraction pattern
   could be described with two-dimensional hexagonal unit cell [a
   =5.685(i) angstrom, symmetry group p6mm]. Structural modeling with a
   continuous electron density approach as well as with a discrete
   disordered atoms distribution was accomplished. The model was refined
   using the Rietveld method. The structure is characterized by a spiral
   arrangement of polymers (CF2-)(n) along the z-axis with complete mutual
   disordering by rotational displacement around z, as well as a partial
   molecular translation along the z-axis. Molecular disordering results
   in a systematic absence of reflections with 1 not equal 0 and as a
   sequence in two-dimensional unit cell effect. The presence of complete
   rotational disordering distinguishes the ultra-dispersed form of
   polytetrafluoroethylene from the standard one (fluoroplast-4), where
   only partial disordering is observed.


Muccini, M   Loi, MA   Kenevey, K   Zamboni, R   Masciocchi, N   Sironi, A
Blue luminescence of facial tris(quinolin-8-olato)aluminum(III) in
   solution, crystals, and thin films
ADVANCED MATERIALS 16, 2004, 861-864.

Barea, E   Navarro, JAR   Salas, JM   Masciocchi, N   Galli, S   Sironi, A
Mineralomimetic sodalite- and muscovite-type coordination frameworks.
   Dynamic crystal-to-crystal interconversion processes sensitive to ion
   pair recognition


Bonnet, PA   van de Streek, J   Trask, AV   Motherwell, WDS   Jones, W
The crystal structure of an unstable polymorph of beta-D-allose
CRYSTENGCOMM 6, 2004, 535-539.
The crystal structure of a new polymorph, Form II, of beta-D-allose has
   been determined by X-ray powder diffraction. The unit cell is
   hexagonal, a = b = 16.598 Angstrom, c = 4.856 Angstrom, alpha = beta =
   90degrees, gamma = 120degrees, space group P6(2) with Z = 6, Z' = 1.
   The molecule adopts the C-4(1) chair-conformation, with a torsional
   change of conformation of the O6 side-chain compared to the
   orthorhombic Form I. The two polymorphs share a common feature of a
   stacked hydrogen bonded column of molecules in the short axis
   direction. The structures differ in hydrogen linking of these columns.
   The more stable Form I has more immediate neighbours linked by hydrogen
   bonds to a reference molecule, and higher crystal density than Form II.

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Armel Le Bail