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Keller, HL    Wimbert, L
On coinage metal mercury chalcogenide halides. III. On the crystal
   structure of Ag2HgSI2
Ag2HgSI2, was obtained as a yellow powder by heating a mixture of AgI
   and alpha-HgS at 120degreesC. The compound crystallizes in space group
   type Cmc2(1) with a = 1384.35(6) pm, b = 746.97(3) pm, c = 710.29(3) pm
   and Z = 4. The structure consists of a distorted hexagonal closed
   package of sulphur and iodine, in which a third of the tetrahedral
   spaces is occupied by silver and a third of the octahedral spaces is
   occupied by mercury. The distortion of the hexagonal structure is
   caused by the need of space of the lone pairs at sulphur and iodine.
   This was shown by the calculation of the electron localisation function  (ELF).

2003-2  ??

Petrova, SA   Mar'evich, VP   Zakharov, RG   Selivanov, EN   Chumarev, VM   Udoeva, LY
Crystal structure of zinc calcium oxysulfide
DOKLADY CHEMISTRY 393, 2003, 255-258.


Pompetzki, M   Dinnebier, RE   Jansen, M
Sodium dithiophosphate(V): Crystal structure, sodium ionic conductivity
   and dismutation
SOLID STATE SCIENCES 5, 2003, 1439-1444.
Na3PO2S2 was synthesized from the corresponding undecahydrate by
   freeze-drying. It dismutates at temperatures above 350 C into Na3PO3S
   and Na3POS3. The crystal structure of Na3PO2S2 was determined from
   X-ray powder diffraction data, and refined using the Rietveld technique
   (Pbca, a = 17.5359(2) Angstrom, b = 11.3044(1) Angstrom, c = 5.8656(1)
   Angstrom, R-F2 = 8.45%, R-p = 4.80%, R-wp = 6.79%). The baricenters of
   the PO2S2-tetrahedra are arranged in the sense of a hexagonal close
   packing. One of the P-O bonds of these tetrahedra is oriented parallel
   to the crystallographic c-axis with the POS2-groups in an eclipsed
   mutual orientation. The crystal structure of Na3PO2S2 displays a close
   relationship to the ones of Ca3CrN3 and Na3POS3. Above 330 degreesC,
   Na3PO2S2 can be regarded as a fast ionic conductor (with sigma > 10(-5)
   S cm(-1)).


Fukuda, K    Fukutani, K
Crystal structure of calcium zirconium diorthophosphate, CaZr(PO4)(2)
POWDER DIFFRACTION 18, 2003, 296-300.
The crystal structure of CaZr(PO4)(2) was determined from conventional
   X-ray powder diffraction data using direct methods, and it was further
   refined by the Rietveld method. The structure was orthorhombic (space
   group P2(1)2(1)2(1), Z = 4) with a = 1.44876(4), b = 0.67213(1), c =
   0.62347(2) nm, and V = 0.60710(3) nm(3). Final reliability indices were
   R-wp = 6.49%, R-B = 2.43%, and S = 1.32. The Ca atom is sevenfold
   coordinated, and the Ca atom and surrounding oxygen atoms form a
   distorted capped octahedron with a mean Ca-O distance of 0.243 nm. The
   ZrO7 coordination polyhedron is a distorted pentagonal bipyramid with a
   mean Zr-O distance of 0.216 nm. CaO7, ZrO7, and PO4 polyhedra share
   edges to form infinite chains with the composition
   [CaO(3)ZrO(3)p(2)O(8)](12-) along the [010]. Individual chains are
   linked together, forming a two-dimensional sheet parallel to (100).
   These sheets are stacked in the [100] direction to form a
   three-dimensional structure.


Ferreira, A   Lin, Z   Soares, MR   Rocha, J
Ab initio structure determination of novel small-pore metal-silicates:
   knots-and-crosses structures
Sodium chloride stannosilicate AV-13 (Na2.26SnSi3O9Cl0.26.xH(2)O) and
   zirconium and hafnium analogues of this material have been prepared and
   their structures solved from powder X-ray diffraction data using direct
   methods, and Na-23, Si-29 and Sn-119 solid-state NMR. AV-13 materials
   are small-pore solids, probably more adequately described as tunnel
   structures. The AV-13 framework consists of corner-sharing MO6 (M = Sn,
   Zr, Rf) octahedra and SiO4 tetrahedra. The latter form six-membered
   [Si6O18](12-) rings, which are interconnected by MO6 octahedra. The
   structure is better understood by considering a three-dimensional
   knots- and-crosses lattice. In a given layer, successive distorted-cube
   M-8 cages contain [Na6-x(H2O)](H2O,Cl-) octahedra (knots) and
   cyclohexasilicate (crosses) units. While the former are extra-framework
   species, the six-membered rings are, of course, part of the framework.
   The cages are accessed via seven-membered [M3Si4O27](26-) windows, with
   free aperture ca. 2.3 x 3.2 Angstrom, one per each pseudo-cube face.
   Pilling up layers generates the structure, with knots-and-crosses
   alternating. The non-framework five-coordinated Na cations are


Burton, A   Elomari, S   Chen, CY   Medrud, RC   Chan, IY   Bull, LM
   Kibby, C   Harris, TV   Zones, SI   Vittoratos, ES
SSZ-53 and SSZ-59: Two novel extra-large pore zeolites
The syntheses, structure solutions, and physicochemical and catalytic
   characterizations of the novel zeolites SSZ-53 and SSZ-59 are
   described. SSZ-53 and SSZ-59 were synthesized under hydrothermal
   conditions with the [1-(4-fluorophenyl)cyclopentylmethyl]trimethyl
   ammonium cation and 1-[1-(4-chlorophenyl)cyclopentylmethyl]-1-methyl
   azocanium cation, respectively, as structure-directing agents. The
   framework topology of SSZ-53 was solved with the FOCUS method, and the
   structure of SSZ-59 was determined by model building. Rietveld
   refinement of synchrotron X-ray powder diffraction data confirms each
   proposed model. SSZ-53 and SSZ-59 each possess a one-dimensional
   channel system delimited by 14-membered rings. Results from
   transmission electron microscopy, electron diffraction, catalytic
   experiments (spaciousness index and constraint index tests), and argon
   and hydrocarbon adsorption experiments are consistent with the proposed


Ferreira, A   Ananias, D   Carlos, LD   Morais, CM   Rocha, J
Novel microporous lanthanide silicates with tobermorite-like structure
The synthesis and structural characterization of microporous lanthanide
   silicates (Na(1.08)K(0.5)Ln(1.14-)Si(3)O(8.5).1.78H(2)O, Ln = Eu, Tb,
   Sm, Ce) are reported. The structure of these solids is closely related
   with the structure of hydrated calcium silicate minerals known as
   tobermorites and was solved by powder X-ray diffraction ab initio
   (direct) methods and further characterized by chemical analysis,
   thermogravimetry, scanning electron microscopy, Na-23 and Si-29 MAS NMR
   and luminescence spectroscopy. These materials combine microporosity
   with interesting photoluminescence properties, and their structural
   flexibility allows fine-tuning of luminescence properties, by
   introducing a second type of lanthanide ion in the framework. Thus,
   they may find applications in new types of sensors.


Zavalij, PY   Yang, SF   Whittingham, MS
Structures of potassium, sodium and lithium bis(oxalato)borate salts
   from powder diffraction data
The crystal structures of the alkali-metal bis(oxalato) borate salts
   A[B(C2O4)(2)] (A = K, Na, Li) have been determined ab initio using
   powder diffraction data obtained from a laboratory diffractometer. The
   K compound crystallizes in the orthorhombic space group Cmcm and its
   structure has been solved by direct methods applied to the integrated
   intensities from full pattern decomposition. The Na compound is
   isostructural with the K salt, while the crystal structure of the
   highly hydroscopic Li compound differs from the other two. It has an
   orthorhombic lattice, space group Pnma, and its structure was solved by
   the global optimization method using a parallel tempering approach. In
   the K and Na structures the metal ions and complex borate ions form
   chains with m2m symmetry. Metal - oxygen bonding between the chains
   links them into a layer and then a framework with square tunnels. The
   coordination number of both K and Na is eight. The Li compound also
   contains chains that have. m. symmetry and are bound together into a
   three-dimensional framework. The coordination polyhedron of the Li atom
   is a square pyramid with Li lying in its base. This square pyramidal
   coordination leads to its high reactivity with moisture to give
   Li[B(C2O4)(2)] H2O with lithium in six coordination.


Chernyshev, VV   Machon, D   Fitch, AN   Zaitsev, SA   Yatsenko, AV
   Shmakov, AN   Weber, HP
Protonation site and hydrogen bonding in anhydrous and hydrated
   crystalline forms of doxazosin mesylate from powder data
The three-dimensional solid-state structures of two modifications of
   doxazosin mesylate C23H26N5O5+.CH3SO3-, 4-amino-2-[
   4-[(2,3-dihydro-1,4-benzodioxin-2-yl) carbonyl] piperazin-1-yl]-
   6,7-dimethoxyquinazoline methanesulfonate, a commonly used
   antihypertensive agent, have been determined by synchrotron X-ray
   powder diffraction. An anhydrous form (A) and a dihydrate form (dG)
   crystallize in monoclinic space groups. In both forms the doxazosin
   molecule is protonated at the N1 atom of the quinazoline bicycle. The
   N1 atom, and the amino H atoms and O atoms of the mesylate moieties are
   involved in three-dimensional hydrogen-bonding networks, while solvent
   water molecules and carboxamide O atoms are also incorporated in a
   hydrogen-bonding network in dG.


Miura, H   Ushio, T   Nagai, K   Fujimoto, D   Lepp, Z   Takahashi, H   Tamura, R
Crystallization of a desired metastable polymorph by pseudoseeding,
   crystal structure solution from its powder X-ray diffraction data, and
   confirmation of polymorphic transition
CRYSTAL GROWTH & DESIGN 3, 2003, 959-965.
Described are the successful, selective crystallization and
   characterization of one (delta-form) of the metastable polymorphs of
   fonium p-toluenesulfonate (1a), which is assumed to exist as a
   transient key-intermediate crystalline phase relevant to the mechanism
   of Preferential Enrichment, an unusual enantiomeric resolution
   phenomenon observed upon crystallization of a certain kind of racemates
   from solvents. By pseudoseeding the supersaturated solution with the
   delta-form seed crystals of an anlogous compound, the desired
   delta-form crystals of (+/-)-1a could be obtained as a monophasic
   powder sample. This selective crystallization can be interpreted in
   terms of the interplay between an inhibition of the nucleation or
   crystal growth process of the undesired stable alpha-polymorphic form
   and a heterogeneous nucleation of the desired metastable delta-form
   through epitaxy. The physicochemical properties of the delta-form.
   crystal such as melting point and solubility have been compared with
   those of the stable alpha-form one to evaluate the relative stability
   of the metastable delta-form. It has also been confirmed that
   polymorphic transition of the metastable delta-form crystal to the
   stable alpha-form one occurs in contact with a solvent. On the basis of
   the delta-form crystal structure solved from its powder X-ray
   diffraction data measured with a laboratory X-ray source by means of
   the direct-space approach employing the Monte Carlo method and the
   subsequent Rietveld refinement, the origin of the metastability of the
   delta-form crystal has been discussed.


Fujimoto, D   Tamura, R   Lepp, Z   Takahashi, H   Ushio, T
Mechanism of a new type of solvent-assisted solid-to-solid polymorphic
   transition causing preferential enrichment: Prominent influence of
   C(sp(2))H ...O interaction on the control of a crystal structure
CRYSTAL GROWTH & DESIGN 3, 2003, 973-979.
A new mode of the solvent-assisted solid-to-solid transformation of the
   first-formed and least stable gamma-polymorphic form into the most
   stable epsilon-polymorphic one occurring during crystallization from
   the supersaturated EtOH solution of
   monium benzenesulfonate [(+/-)-2], which shows an unusual enantiomeric
   resolution phenomenon called Preferential Enrichment, has been
   revealed. The crystal structure of the new epsilon-form, which was
   obtained as the monophasic powder sample by exhaustive polymorphic
   transitions via three other metastable polymorphic forms in contact
   with the solvent, has been solved from the powder X-ray diffraction
   data by the direct-space approach employing the Monte Carlo method with
   the subsequent Rietveld refinement. By comparison of the crystal
   structure of the least stable gamma-form with that of the most stable
   epsilon-one, the mechanism of this polymorphic transition has been
   interpreted in terms of a new type of rearrangement of weak
   intermolecular interactions caused by a slight molecular movement
   inside the crystal lattice, in which intermolecular C(sp(2))H...O
   interactions prominently control the crystal structure. This new
   finding complements our recent report on the mechamisn of Preferential


Montejo-Bernardo, JM   Garcia-Granda, S   Bayod-Jasanada, MS   Llavona-Diaz, L   Llorente, I
X-ray study of the pseudopolymorphism of the azithromycin monohydrate
A combination of X-ray powder diffraction and single crystal studies on
   azithomycin pseudopolymorphs give the precise solid state composition
   of all monohydrate pseudopolymorphs reported. According to the X-ray
   results the four monohydrates of azithromycin studied have the same
   crystallographic parameters. Furthermore, the analysis of the relative
   intensities from the powder patterns points to very similar chemical
   compositions and crystal structures. This result has been confirmed by
   the single crystal studies. The single crystal studies show that the
   solid state conformation of the azithromycin molecules is affected by
   the presence of solvents. The solvent methanol molecules were found
   disordered probably due to the existence of many positions where the
   hydrogen bonding is favoured and the large size of the available space
   to host the solvents.


Cheung, EY   Harris, KDM   Johnston, RL   Hadden, KL   Zakrzewsk, M
Polymorphism of a novel sodium ion channel blocker
2-{[4-(4-Fluorophenoxy)phenyl]-methylene}-hydrazinecarboxamide,a member
   of the semicarbazone family which has shown potential therapeutic use
   as anticonvulsants, has been found to exist in two polymorphic forms
   denoted A and B. In addition to reporting aspects of the physical
   characterization of both forms, the crystal structure of polymorph A
   has been determined directly from powder X-ray diffraction data using
   the Genetic Algorithm technique for structure solution, followed by
   Rietveld refinement. This structure is compared with that of polymorph
   B, which was determined previously from single crystal X-ray
   diffraction data. Knowledge of the crystal structures of the two
   polymorphs provides the opportunity for establishing structure-property
   relationships. This work further emphasizes the scope and utility of ab
   initio structure solution from powder X-ray diffraction data in the
   pharmaceuticals field.

2003-14  - failed...  ??

Masciocchi, N   Castelli, F   Forster, PM   Tafoya, MM   Cheetham, AK
Synthesis and characterization of two polymorphic crystalline phases
   and an amorphous powder of nickel(II) bisimidazolate
INORGANIC CHEMISTRY 42, 2003, 6147-6152.
Nickel(II) bisimidazolate is polymorphic. Depending on the synthetic
   strategy adopted, two crystalline phases (alpha- and beta-Ni(im)(2)) or
   an amorphous material of the same composition can be prepared. The
   thermodynamically stable alpha-Ni(im)(2) phase, which can be prepared
   in water at elevated temperatures, contains a two-dimensional polymer
   (of nearly square meshes) with square-planar NiN4 chromophores and
   exo-bidentate imidazolate ligands bridging nickel atoms that are ca.
   5.73 Angstrom apart. The beta-Ni(im)(2) Phase can be kinetically
   stabilized at lower temperatures, but the structural complexity and the
   lack of single crystals prevented its full structural characterization,
   even in the presence of an indexed powder diffraction pattern. The
   spectroscopic features of these crystalline phases are compared with
   those of the amorphous material.


Le Bail, A   Stephens, PW   Hubert, F
A crystal structure for the souzalite/gormanite series from synchrotron
   powder diffraction data
In absence of suitable single crystal due to polysynthetic twinning,
   the crystal structure of a specimen in the souzalite/gormanite series
   (Fe,Mg)(3)(Al,Fe)(4)(PO4)(4)(OH)(6).2H(2)O is determined ab initio from
   synchrotron powder diffraction data. The crystals belong to space group
   P (1) over bar, the cell is different from previously reported with
   a=7.2223(1), b=11.7801(1), c=5.1169(1) Angstrom; alpha=90.158(1),
   beta=109.938(1), gamma=81.330(1)degrees; V=404.02(1) Angstrom(3); Z=1.
   The structure consists of infinite chains of alternating [FeO6], [MgO6]
   and [AlO6] octahedra sharing faces and/or edges. These chains are
   connected by corners with clusters of three corner-sharing [AlO6]
   octahedra, forming octahedral layers which are interconnected by [PO4]
   groups. A comparison with other minerals of similar composition and
   structure is made (dufrenite, burangaite).


Tafeenko, VA   Chernyshev, VV   Yatsenko, AV   Makarov, VA   Sonneveld, EJ
   Peschar, R   Schenk, H
Intermolecular -CH3  .   .   .  O2N-contacts in
   two polymorphic modifications of (1E)-N
The title compound was synthesized and isolated in two crystal
   modifications. The structure of the orthorhombic modification was
   determined by the X-ray powder diffraction method and the structure of
   the monoclinic modification was determined using the X-ray
   single-crystal diffraction technique. The molecules in both polymorphs
   are E, E isomers. Intermolecular H3C...NO2 contacts and their role in
   the formation of the polymorphic modifications are analyzed.


Masciocchi, N   Ardizzoia, GA   Brenna, S   Castelli, F   Galli, S
   Maspero, A   Sironi, A
Synthesis and ab-initio XRPD structure of group 12 imidazolato polymers
CHEMICAL COMMUNICATIONS iss 10, 2003, 2018-2019.
Two new 3D homoleptic binary imidazolates, Cd(im)(2) and Hg(im)(2) (Him
   = imidazole), as well as [Hg(im)]NO3, containing 1D polycations of
   [Hg(im)](n)(n+) formulation, have been prepared and characterized by
   ab-initio XRPD methods.


Ivashkevich, LS   Lyakhov, AS   Selevich, AF   Petrusevich, YI
The crystal structure of Er(HPO4)(NO3) .  3 H2O: ab initio
   determination from X-ray powder diffraction data
The crystal structure of orthorhombic Er(HPO4)(NO3) . 3 H2O has been
   determined from X-ray powder diffraction data. The unit cell dimensions
   are a = 10.1653(4) Angstrom, b = 11.9178(5) Angstrom, c = 6.8533(3)
   Angstrom, V = 830.26(6), Z = 4. The space group is Pbcm (No. 57) or
   Pbc2(1) (No. 29). The structures were solved ab initio using EXPO
   program and refined by FULLPROF package.
   Because geometrical features of the two solutions are the same, the
   crystal structure has been described in the scope of the
   centrosymmetric Pbcm space group. Positions of the hydrogen atoms were
   not defined. The erbium atom is eight coordinated. It is surrounded by
   one nitrate anion, one water molecule and four phosphate groups. [ErO8]
   polyhedra are linked together through their edges forming infinite
   chains extended along the c axis. The chains are connected by phosphate
   groups to form layers palallel to the yz plane. Probable hydrogen bonds
   are discussed.


Nowell, H   Shan, N   Attfield, JP   Jones, W   Motherwell, WDS
The structure of cyclohexane-1, 3cis, 5cis-tricarboxylic acid,
   determined from powder X-ray diffraction data
The previously unknown crystal structure of cyclohexane-1, 3cis,
   5cis-tricarboxylic acid (CTA) has been solved from laboratory X-ray
   powder diffraction data using a simulated annealing algorithm followed
   by restrained Rietveld refinement (reduced-chi(2) = 8.531 for the
   refined crystal structure). The structure is triclinic (P (1) over bar,
   Z = 4). Five out of six of the CO2H groups in the asymmetric unit form
   R-2(2)(8) hydrogen bond motifs with neighbouring CO2H groups. The
   motifs connect molecules to form pseudo-hexagonal, ten-molecule rings
   that fuse into supramolecular buckled honeycomb sheets, which stack and
   are linked by O-(HO)-O-... hydrogen bonds.


Masciocchi, N   Brenna, S   Galli, S   Maspero, A
Ab-initio XRPD structural characterization of coordination polymers:
   the case of [Ag(C3H3N2CS2)]
The crystal structure of the one-dimensional polymer [Ag(C3H3N2CS2)]
   has been determined from conventional X-ray powder diffraction methods,
   through simulated annealing and Rietveld refinement techniques
   [Ag(C3H3N2CS2)] is monoclinic, P2(1)/c; a = 8.409(l), b = 11.740(l), c
   = 6.721(l) Angstrom, beta = 101.86(2)degrees, V = 649.3(2) Angstrom(3);
   Z = 4; rho = 2.566 g cm(-3) Final R-wp, R-p and R-F agreement factors,
   for 3 100 data points collected in the 8-70degrees 2theta range, are
   0.091, 0.071 and 0.058, respectively. Anisotropic peak shapes and
   high-angle tails for the 0k0 (and neighboring) reflections suggest that
   the polymeric chains, aligned along b, suffer from a partial disorder,
   in that packing of adjacent molecules does not conform to a rigorous
   crystalline, truly periodic, tiling.


Ivashevskaja, SN    Aleshina, LA   Andreev, VP   Nizhnik, YP
   Chernyshev, VV   Schenk, H
4-(4 '-dimethylaminostyryl)pyridine N-oxide from powder data
The crystal structure of 4-(4-dimethylaminophenylethenyl)pyridine
   N-oxide, C15H16N2O, has been determined from X-ray laboratory powder
   diffraction data. The powder pattern was indexed with a monoclinic unit
   cell with a long a axis. The structure was solved by a grid search
   technique. The subsequent bond-restrained Rietveld refinement gave bond
   lengths and angles within expected ranges.


Grzechnik, A   Bouvier, P   Farina, L
High-pressure structure of Li2CO3
The high-pressure behavior of Li2CO3 is studied up to 25 GPa with
   synchrotron angle-dispersive powder X-ray diffraction in diamond anvil
   cells and synthesis using a multi-anvil apparatus. A new non-quenchable
   hexagonal polymorph (P6(3)/mcm, Z = 2) occurs above 10 GPa with
   carbonate groups in a staggered configuration along the c-axis-a =
   4.4568(2) Angstrom and c = 5.1254(6) Angstrom at 10 GPa. Two columns of
   face-shared distorted octahedra around the Li atoms are linked through
   octahedral edges. The oxygen atoms are coordinated to one carbon atom
   and four lithium atoms to form a distorted square pyramid. Splittings
   of X-ray reflections for the new polymorph observed above about 22 GPa
   under non-hydrostatic conditions arise from orthorhombic or monoclinic
   distortions of the hexagonal lattice. The results of this study are
   discussed in relation to the structural features found in other Me2CO3
   carbonates (Me: Na, K, Rb, Cs) at atmospheric conditions.


Le Bail, A    Mercier, AM
Distorted chiolite crystal structures of alpha-Na5M3F14 (M=Cr,Fe,Ga)
   studied by X-ray powder diffraction
POWDER DIFFRACTION 18, 2003, 128-134.
The crystal structures of the chiolite-related room temperature phases
   alpha-Na5M3F14 (M-III =Cr,Fe,Ga) are determined. For all of them, the
   space group is P2(1)/n, Z=2; a= 10.5096(3) Angstrom, b=7.2253(2)
   Angstrom, c=7.2713(2) Angstrom, beta=90.6753(7)degrees (M = Cr); a=
   10.4342(7) Angstrom, b = 7.3418(6) Angstrom, c = 7.4023(6) Angstrom,
   beta=90.799(5)degrees (M = Fe), and a= 10.4052(1) Angstrom, b=7.2251(1)
   Angstrom, c=7.2689(1) Angstrom, beta=90.6640(4)degrees (M = Ga).
   Rietveld refinements produce final R-F factors 0.036, 0.033, and 0.035,
   and R-WP factors, 0.125, 0.116, and 0.096, for M-III=Cr, Fe, and Ga,
   respectively. The MF6 polyhedra in the defective isolated
   perovskite-like layers deviate very few from perfect octahedra. Subtle
   octahedra tiltings lead to the symmetry decrease from the P-4/mnc space
   group adopted by the Na5Al3F14 chiolite aristotype to the P2(1) In
   space group adopted by the title series. Facile twinning precluded till
   now the precise characterization of these compounds.


Crichton, WA   Mezouar, M   Monaco, G   Falconi, S
Phosphorus: New in situ powder data from large-volume apparatus
POWDER DIFFRACTION 18, 2003, 155-158.
Improved X-ray powder diffraction data for orthorhombic phosphorus,
   S.G. Cmca (64) obtained in situ at synthesis conditions of 1.2 GPa and
   1100 K, are described. Representative, as synthesized, data include
   2.552(X), 3.320(4), 2.595(3), 5.191(2), 1.630(2), for least-squares
   unit-cell a=3.3182(6) Angstrom, b= 10.3744(18) Angstrom and c=4.3227(9)
   Angstrom. As an illustration of the quality of the data, the structure
   was solved from powder XRD and Rietveld refined to give a=3.3199(2)
   Angstrom, b= 10.3678(4) Angstrom, c=4.3154(2)Angstrom, and
   V=148.535(12) Angstrom(3) with the P atom on 8f (1/2, y,z) with
   y=0.1044(22) and z=0.9179(7). (C) 2003 International Centre for
   Diffraction Data.
P, Cmca, synchrotron data


Grzechnik, A   Crichton, WA   Gesland, JY
Potassium triyttrium decafluoride, KY3F10, synthesized at high
   pressures and high temperatures
SOLID STATE SCIENCES 5, 2003, 757-764.
Potassium triyttrium decafluoride, KY3F10, has been studied at high
   pressures and high temperatures using in situ synchrotron
   angle-dispersive X-ray powder diffraction in a Paris-Edinburgh cell and
   syntheses in a multi-anvil apparatus. At ambient conditions this
   compound exhibits a 2 x 2 x 2-fluorite superstructure (Fm (3) over
   barm, Z = 8, a = 11.54315(1) Angstrom) with yttrium atoms displaced
   from the ideal fcc positions. Upon compression to above 7.5 GPa at room
   temperature, a new polymorph is formed (Pm (3) over barn, Z = 1, a =
   5.70485(8) Angstrom for the sample synthesized at 10.5 GPa and 298 K)
   with potassium and yttrium atoms in the ideal fluorite positions.
   Fluorine atoms are disordered and split on partially occupied sites.
   The same phase of KY3F10 is obtained at lower pressures and high
   temperatures. This new structure is discussed in relation to other
   fluorite superstructures.


Masciocchi, N   Galli, S   Sironi, A   Barea, E   Navarro, JAR   Salas, JM   Tabares, LC
Rich structural and magnetic chemistry of cobalt(II) pyrimidin-2-olate
   and pyrimidin-4-olate complexes. Synthesis, X-ray powder diffraction
   studies, and thermal behavior
CHEMISTRY OF MATERIALS 15, 2003, 2153-2160.
Two new cobalt(II) species containing the pyrimidin-4-olate ligand
   (4-pymo) have been prepared and fully characterized by spectroscopic,
   thermal, and ab initio X-ray powder diffraction methods. The magnetic
   properties of both these species and Co(2-pymo)(2), an extended
   cobalt(II) compound containing the pyrimidine-2-olate ligand (2-pymo),
   are also reported. Co(4-pymo)(2)(H2O)(4) (1) [orthorhombic, Pcab, a =
   13.5233(4) Angstrom, b = 12.9617(3) Angstrom, and c = 6.7925(2)
   Angstrom] consists of D-4h octahedral monomers, bearing axial 4-pymo
   ligands, interlinked by an extensive network of OH...X (X = O, N)
   hydrogen bonds. Upon heating, it loses water and transforms into an
   amorphous (above 150 degreesC) (2a) or a polycrystalline above 320
   degreesC) Co(4-pymo)(2) phase (2b) [orthorhombic, Imma, a = 6.5720(8)
   Angstrom, b = 6.6209(8) Angstrom, and c = 20.688(2) Angstrom]. In the
   latter, C-2v pseudo-tetrahedral cobalt(II) ions are linked by 4-pymo
   ligands in the unusual N,O-exo-bidentate mode, generating 2D layers of
   nearly square meshes, thus significantly differing from the
   Co(2-pymo)(2) analogue (3), in which N,N'-exo-bidentate bridges
   generate an acentric, 3D diamondoid network. The thermal dependence of
   the magnetic susceptibility has been studied for all the above
   compounds (1, 2a, 2b, and 3) in the 2-300 K temperature range. The
   magnetic behavior of 1 is dominated by spin-orbit coupling of
   magnetically isolated octahedral Co(II) centers. The extended materials
   2a and 2b show antiferromagnetic exchange between distorted tetrahedral
   metal centers, whereas 3 behaves as a spin-canted antiferromagnet, a
   ferromagnetic ordering taking place below a critical temperature, T-c =
   23 K; 3 can thus be considered as a molecular magnet. Indeed, magnetic
   hysteresis studies on 3 at 4.8 K yield a coercitive field H-coer = 3900
   G and a remnant magnetization M-rem = 279 cm(3) G mol(-1).


Cecconi, F   Dominguez, S   Masciocchi, N   Midollini, S   Sironi, A   Vacca, A
Complexation of beryllium(II) ion by phosphinate ligands in aqueous
   solution. Synthesis and XRPD structure determination of
INORGANIC CHEMISTRY 42, 2003, 2350-2356.
Two bifunctional ligands, phenyl(carboxymethyl)phosphinate (ccp(2-))
   and P,P'-diphenylmethylenediphosphinate (pcp(2-)), have been tested as
   chelating agents of beryllium(II). Both ligands have the same charge
   and a similar chelating structure, but whereas the 1:1 adduct of
   pcp(2-), Be(pcp)((HO)-O-2)(2), could be isolated as a white powder, no
   pure compound could be isolated from solutions containing beryllium(II)
   and ccp(2-). Instead, the solutions were examined by means of
   potentiometry and Be-9 NMR spectroscopy. Analysis of the potentiometric
   titration data with the program HYPERQUAD suggested the formation of
   the complex species BeL, [BeHL](+), [BeL2](2-), and [BeHL2](-) (L =
   ccp). The formation constants for these species were determined at 25
   degreesC and / = 0.5 mol dm(-3) NaCIO4. The Be-9 NIVIR spectra are
   consistent with this model. The formation constants found for the
   ccp(2-) complexes are lower than those reported for related phosphonate
   ligands. However, the effective stability constant (which gives a
   better indication of the intrinsic coordinating capacity of the ligand
   at a particular pH) of the complex [Be(ccp)(2)](2-) at pH < 4 is
   greater than the effective constants of the corresponding
   phosphonoacetate and methylenediphosphonate complexes. The structure of
   Be(pcp)(H2O)(2) was determined by X-ray powder diffraction methods and
   consists of discrete molecules interconnected by an extended 2D network
   of hydrogen bonds, resulting in a stacking of double layers with a
   polar core and a lipophilic surface. Crystal data: C13H16BeO6P2, fw
   339.21, monoclinic P2(1)/c, a 16.174(1) Angstrom, b = 8.979(1)
   Angstrom, c = 10.929(1) Angstrom, beta = 90.398(9)degrees, V =
   1587.2(3) Angstrom(3), Z = 4.


Boullay, P   Mercurio, D   Bencan, A   Meden, A   Drazic, G   Kosec, M
An XRPD ab-initio structural determination of La2RuO5
The crystal structure of a new oxide, La2RuO5, was determined ab initio
   using conventional laboratory X-ray powder diffraction. Combining X-ray
   and electron diffraction techniques, we found that the new phase
   crystallized in the monoclinic system with the space group P2(1)/c (SG
   no.14) and the cell parameters a 9.1878(2) Angstrom, b=5.8313(2)
   Angstrom, c 7.9575(2) Angstrom and beta=100.773(2)degrees (V=418.8
   Angstrom(3), Z=4). The structural determination with the Patterson
   method and Fourier difference syntheses and the final Rietveld
   refinement were performed by means of the JANA2000 program. The
   structure is built up from the regular stacking, of a two octahedra
   thick [LaRuO4](infinity) zigzag perovskite slab and an original similar
   to3.4 Angstrom thick [LaO](infinity) slab which constitutes the key
   feature of this new structure. (C) 2002 Elsevier Science (USA). All
   rights reserved.


Juarez-Arellano, EA   Bucio, L   Hernandez, JA   Camarillo, E
   Carbonio, RE   Orozco, E
Synthesis, crystal structure, and preliminary study of luminescent
   properties of InTbGe2O7
A new indium terbium germanate InTbGe2O7, which is a member of the
   thortveitite family, was prepared as a polycrystalline powder material
   by high-temperature solid-state reaction. This new compound
   crystallizes in the monoclinic system, space group C2/c (No. 15), with
   unit cell parameters a = 6.8818(2)Angstrom, b = 8.8774(3)Angstrom, c =
   9.7892(4)Angstrom, beta = 101.401 (1)degrees V = 586.25(4)Angstrom(3)
   and Z = 4. Its structure was characterized by Rietveld refinement of
   powder laboratory X-ray diffraction data. It consists of octahedral
   sheets that are held together by sheets of isolated Ge2O7 diorthogroups
   composed of two tetrahedra sharing a common vertex. It contains only
   one octahedral site occupied by In3+ and Tb+3 cations. The
   characteristic mirror plane in the thortveitite (SC2Si2O7) space group
   (C2/m, No. 12) is not present in this new compound. Besides, in
   InTbGe2O7, the Ge-O-Ge angle bridging two diorthogroups is
   156.8(2)degrees as compared to the one in thortveitite, which is
   180degrees. On the other hand, luminescent properties were observed
   when it is excited with 376.5 nm wavelength. The luminescence spectrum
   shows typical transitions from the D-5(4) multiplet belonging to the
   trivalent terbium ion.


Hassfjell, S   Kongshaug, KO   Romming, C
Synthesis, crystal structure and chemical stability of bismuth(III)
   complexed with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene
   phosphonic acid (H8DOTMP)
DALTON TRANSACTIONS 2003, 1433-1437.
The potential use of the alpha-particle emitting compounds Bi-212/213
   -DOTMP and Pb-212-DOTMP in therapy of bone-associated cancers, and
   medical interest in bismuth compounds, motivated this study. Syntheses
   of the Bi(III) and Pb(III) complexes of
   1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid
   (H8DOTMP) are reported. Extensive pH-stability was found for both
   complexes, in the pH range 0-13 for Bi-DOTMP and pH 4-14 for Pb-DOTMP.
   Furthermore, both complexes formed within 1 min in the pH range 6-10 at
   10 muM metal-ion and 15 muM DOTMP. Single crystals of [NaBi(H4DOTMP)]
   and polycrystalline [Bi(H5O2)(H4DOTMP)] were formed and characterized
   by single crystal and powder X-ray diffraction methods, respectively.
   The structure of the anion was found in both salts to exhibit a square
   antiprismatic eight-coordination with a four-fold axis of symmetry.


Bellitto, C   Bauer, EM   Ibrahim, SA   Mahmoud, MR   Righini, G
Synthesis, X-ray powder structure, and magnetic properties of layered
   Ni-II methylphosphonate, [Ni(CH3PO3)(H2O)], and Ni-II
   octadecylphosphonate, [Ni{CH3-(CH2)(17)-PO3}(H2O)]
[Ni(CH3PO3)(H2O)] (1) and [Ni[CH3-(CH2)(17)-PO3}(H2O)] (2) were
   synthesised by reaction of NiCl2 . 6H(2)O and the relevant phosphonic
   acid in water in presence of urea. The compounds were characterised by
   elemental and thermogravimetric analyses, UV-visible and IR
   spectroscopy, and their magnetic properties were studied by using a
   SQUID magnetometer. The crystal structure of I was determined ''ab
   initio" from X-ray powder diffraction data and refined by the Rietveld
   method. The crystals of 1 are orthorhombic, space group Pmn2(1), with a
   = 5.587(1), b = 8.698(1), c = 4.731(1) Angstrom. The compound has a
   hybrid, layered structure made up of alternating inorganic and organic
   layers along the b direction of the unit-cell. The inorganic layers
   consist of Ni-II ions octahedrally coordinated by five phosphonate
   oxygen atoms and one oxygen atom from the water molecule. These layers
   are separated by bilayers of methyl groups and van der Waals contacts
   are established between them. A preliminary structure characterisation
   of compound 2 suggests the crystallisation in the orthorhombic system
   with the following unit-cell parameters: a = 5.478(7), b = 42.31(4), c
   = 4.725(3) Angstrom. The oxidation state of the Ni ion in both
   compounds is +2, and the electronic configuration is d(8) (S = 1), as
   determined from static magnetic susceptibility measurements above 50 K.
   Compound 1 obeys the Curie-Weiss law at temperatures above 50 K; the
   Curie (C) and Weiss (0) constants were found to be 1.15 cm(3) K mol(-1)
   and -32 K, respectively. The negative value of theta indicates an
   antiferromagnetic exchange coupling between near-neighbouring Ni-II
   ions. No sign of 3D antiferromagnetic long-range order is observed down
   to T = 5 K, the lowest measured temperature. Compound 2 is paramagnetic
   above T= 50 K, and the values of C and 0 were found to be 1.25 cm(3) K
   mol(-1) and - 24 K, respectively. Below 50 K the magnetic behavior of 2
   is different from that of 1. Zero-field cooled (zfc) and field-cooled
   (fc) magnetisation plots do not overlap below T= 21 K. The irreversible
   magnetisation, DeltaM(fc-zfc), obtained as a difference from fc and zfc
   plots starts to increase at T= 20 K, on lowering the temperature, and
   it becomes steady at T= K. The presence of spontaneous magnetisation
   below T = 20 K indicates a transition to a weak-ferromagnetic state for
   compound 2.


Yamada, H   Shi, WS   Nishikubo, K   Xu, CN
Determination of the crystal structure of spherical particles of
   SrAl2O4 : Eu prepared by the spray method
The crystal structure of spherical particles of Sr0.88Eu0.12Al2O4
   synthesized by the spray method has been investigated by powder X-ray
   diffraction measurements. After annealing at 1300degreesC for 2 h, the
   spheres of Sr0.88Eu0.12Al2O4 crystallize in the hexagonal form with a =
   5.1160(2) Angstrom, c = 8.3722(3) Angstrom, V = 189.77(1) Angstrom(3),
   Z = 2, and space group P6(3)22, which is distinct from the structure
   (monoclinic P2(1)) reported so far. This stable crystal structure was
   refined by the Rietveld method, and it was found that it consists of a
   nondistorted stuffed tridymite structure, and the doped Eu2+ ion is
   located at the same 2b site as the Sr2+ ion. Furthermore, it is
   suggested that such an abnormal stabilization of the hexagonal form at
   ambient temperature is associated with defects of the oxygen ion at the
   2d site based on the electron density map from Fourier synthesis.


Ivashkevich, LS   Lyakhov, AS   Selevich, AF   Lesnikovich, AI
Ab initio structure determination of In2H2(P2O7)(P4O12))(P4O12) from
   X-ray powder diffraction data
The crystal structure of In2H2(P2O7)P4O12) has been determined from
   X-ray powder diffraction data. The structure is orthorhombic, space
   group Pmmn (No. 59), with unit cell dimensions a = 12.9398(2) Angstrom,
   b = 11.3725(3) Angstrom, c = 5.0385(1) Angstrom, V = 741.45(3)
   Angstrom, Z = 2, and D-x = 3.23 g/cm(3). The structure has been solved
   by direct methods using EXPO program and refined by FULLPROF package.
   The final R-Bragg value was 4.6%. Positions of hydrogen atoms were not
   defined. Indium cation has sixfold oxygen coordination being surrounded
   by two diphosphate and four cyclotetraphosphate groups. Probable scheme
   of hydrogen bonding is discussed.


Simon-Masseron, A   Paillaud, JL   Patarin, J
Mu-21: A three-dimensional microporous zincophosphate obtained by
   direct synthesis and reversible dehydration of the zincophosphate Mu-19
CHEMISTRY OF MATERIALS 15, 2003, 1000-1005.
A zincophosphate named Mu-21 (Zn4P8O32H12(C5H12NO)(4)) was obtained in
   solvothermal conditions from a ZnO/H3PO4/N-methylmorpholine/ethylene
   glycol mixture, and its structure was solved ab initio from powder
   data. Mu-21 crystallized in the orthorhombic space group P 2(1)2(1)2(1)
   with a = 10.4200(1), b = 10.4523(2), c = 11.6221(2) Angstrom, and V =
   1265.80(3) Angstrom(3). Mu-21 was also obtained by reversible
   dehydration of the zincophosphate Mu-19 at 80 degreesC. This material
   was characterized by P-31, H-1 MAS NMR, and SEM.


Kiang, YH   Xu, W   Kaufman, MJ
Ab initio structure determination of rofecoxib from powder diffraction
   data using molecular packing analysis method and direct space method
Crystal structures of a COX-II inhibitor, rofecoxib (Vioxx(R)) were
   solved ab initio from X-ray powder diffraction pattern using both
   molecular packing analysis and direct space methods. The X-ray powder
   pattern was indexed into a tetragonal cell. Packing energies were
   generated and analyzed in eight most frequently found tetragonal space
   groups. The two space groups with the lowest total energy, P4(1)2(1)2
   and P4(3)2(1)2, were used for direct space method with a
   Monte-Carlo/Simulated Annealing searching algorithm. Structural
   solutions obtained from direct space method were evaluated using
   molecular packing energy analysis. The structures solved ab initio from
   this work were compared to the single crystal structure deposited in
   the Cambridge Structural Database.


Burton, A   Elomari, S   Medrud, RC   Chan, IY   Chen, CY   Bull, LM   Vittoratos, ES
The synthesis, characterization, and structure solution of SSZ-58: A
   novel two-dimensional 10-ring pore zeolite with previously unseen
   double 5-ring subunits
The synthesis, structure solution, and characterization of the novel
   zeolite SSZ-58 are described. SSZ-58 was synthesized under hydrothermal
   conditions using 1-butyl-1-cyclooctylpyrrolidinium cation as a
   structure-directing agent. The framework topology of SSZ-58 was
   determined with the FOCUS Fourier recycling method. SSZ-58 possesses 12
   tetrahedral atoms in the asymmetric unit of its highest topological
   symmetry, and to date it is the most complex zeolite structure solved
   from powder data. Rietveld refinement of synchrotron powder X-ray
   diffraction data in space group Pmma confirmed the proposed model.
   SSZ-58 contains layers of atoms that are linked together by double
   five-membered rings (D5R), or 5(2)4(5) subunits, that have not been
   observed before in any zeolite or zeotype structures. SSZ-58 possesses
   a two-dimensional channel system consisting of 10-membered ring pores
   that intersect to form large Cavities circumscribed by 12- and
   16-membered ring pores.


Huq, A   Stephens, PW
Subtleties in crystal structure solution from powder diffraction data
   using simulated annealing: Ranitidine hydrochloride
Recent advances in crystallographic computing and availability of
   high-resolution diffraction data have made it relatively easy to solve
   crystal structures from powders that would have traditionally required
   single crystal samples. The success of direct space methods depends
   heavily on starting with an accurate molecular model. In this paper we
   address the applicability of using these methods in finding subtleties
   such as disorder in the molecular conformation that might not be known
   a priori. We use ranitidine HCl as our test sample as it is known to
   have a conformational disorder from single crystal structural work. We
   redetermine the structure from powder data using simulated annealing
   and show that the conformational disorder is clearly revealed by this
   method (C) 2003 Wiley-Liss, Inc.


Jorda, JL   McCusker, LB   Baerlocher, C   Morais, CM   Rocha, J
   Fernandez, C   Borges, C   Lourenco, JP   Ribeiro, MF   Gabelica, Z
Structure analysis of the novel microporous aluminophosphate IST-1
   using synchrotron powder diffraction data and HETCOR MAS NMR
A combination of advanced powder diffraction and NMR techniques have
   allowed the structure of the novel microporous aluminophosphate IST-1
   (\(CH3NH2)(4)(CH3NH3+)(4)(OH-)(4)\[Al12P12O48] to be elucidated. The
   framework structure was determined in the non-centrosymmetric space
   group Pca2(1) (a = 9.61523(1) Angstrom, b = 8.67024(1) Angstrom, c =
   16.21957(2) Angstrom) from high-resolution synchrotron powder
   diffraction data using the program FOCUS. Extra framework species were
   then located on difference electron density maps. A hydroxyl group was
   found to bridge between two of the framework Al atoms, and one
   methylamine species, presumably protonated, could be located in the
   channels where it H-bonds to three framework oxygens. The most unusual
   feature of the structure is the second methylamine molecule, which
   bonds directly to a framework Al atom. The structure is entirely
   consistent with P-31 and Al-27 MAS NMR studies, which showed there to
   be three P (all 4-coordinate) and three At (one 4-, one 5- and one
   6-coordinate) sites, and with C-13 MAS NMR, which showed there to be
   two different types of methylamine species in equal amounts. Assignment
   of the P-31, Al-27 and C-13 MAS NMR signals could be deduced from the
   crystallographic data, P-31-Al-27 HETCOR spectra and ab initio


Blomqvist, H   Ronnebro, E   Kyoi, D   Sakai, T   Noreus, D
Structural characterization of Mg3MnH similar to 6 - a new
   high-pressure phase synthesized in a multi-anvil cell at 6 GPa
With modem X-ray diffraction refinement methods it was shown to be
   possible to identify a new Mg3MnH-6 phase from a minute sample volume
   in spite of poor crystallinity and coexisting impurity phases. The new
   hydride was synthesized at 6 GPa in a high-pressure multi-anvil cell at
   873 K. A monoclinic unit cell was found with a=8.827(2), b=4.657(2),
   c=4.676(2) Angstrom and beta=105.74(2)degrees, space group P2(1)/m (no.
   11), Z = 2, V = 184.99 Angstrom(3). Manganese is surrounded by a
   distorted cube of magnesium with average Mn-Mg distances of 2.78(2)
   Angstrom. The cubes share edges in the b and c directions of the unit
   cell but are separated by a distance of approximate to 3.6 Angstrom
   along a, forming a layered structure. The hydrogen positions were not
   possible to determine, as only a small sample amount could be prepared.
   If the metal atom structure of the title compound is compared to the
   already known Mg3MnH7 it can be concluded that Mg3MnH-6 also consists
   of manganese hydrido complexes counterbalanced by magnesium ions, but
   with a different alignment of the magnesium cubes.


Couhorn, U   Dronskowski, R
Alkali-metal ortho-hydroxyphenolates: Syntheses and crystal structures
   from powder X-ray diffraction
Colorless and highly air- and moisture-sensitive powders of
   M[o-C6H4O(OH)] with M = K, Rb, or Cs have been synthesized from
   reaction mixtures of the appropriate alkali metal and catechol in thf.
   All compounds were structurally characterized by means of powder X-ray
   diffraction using the Rietveld profile refinement technique including
   restraints for the C-C/C-O bond distances and the C-C-C angles. The
   atomic arrangements of M[o-C6H4O(OH)] (K: monoclinic P2(1)/c; Rb/Cs:
   orthorhombic Pbcm) are characterized by polymeric chains of
   (1)(infinity)[M(1)([4])O(2)([2])eta(6)] units connected by hydrogen
   bonds, thereby making up layered structures similar to the one of
   catechol. The coordinatively unsaturated alkali metals are forming
   edge-sharing MO4 pyramids and exhibit asymmetrical eta(6)-interactions
   with the phenylene rings. The symmetry of the unit cells increases with
   increasing size of the cation, and this results in a decrease of the
   monoclinic angle from 118.5degrees (catechol) to 93.7degrees (K
   compound), eventually leading to orthorhombic cells for the Rb and Cs

2003-41  ???

Guillou, N    Livage, C   Drillon, M   Ferey, G
The chirality, porosity, and ferromagnetism of a 3D nickel glutarate
   with intersecting 20-membered ring channels


Tedesco, E   Della Sala, F   Favaretto, L   Barbarella, G   Albesa-Jove, D
   Pisignano, D   Gigli, G   Cingolani, R   Harris, KDM
Solid-state supramolecular organization, established directly from
   powder diffraction data, and photoluminescence efficiency of rigid-core
The "rigid-core" material
   -4,4-dioxide (DTTOMe4) has the highest photoluminescence ever reported
   for thiophene-based molecules in the solid state. We report the
   structure of this material, determined directly from powder X-ray
   diffraction data using the Genetic Algorithm method for structure
   solution, followed by Rietveld refinement, and the structural
   properties are discussed in relation to the structures of the
   corresponding subsystems DTTO and DTTOMe. While the crystal structures
   of the latter compounds contain cofacial dimers, the crystal structure
   of DTTOMe4 comprises layers of molecules aligned in an antiparallel
   fashion. Intermediate neglect of differential overlap with single
   configuration interaction (INDO/SCI) calculations on the intermolecular
   interactions in the three crystal structures show that the different
   solid-state photoluminescence efficiencies of DTTOMe4, DTTOMe, and DTTO
   cannot be correlated with the different types of dipole-dipole
   alignment in the solid state. Instead, photoluminescence efficiencies
   correlate well with the rate of formation of nonradiatively decaying
   charge-transfer pairs upon photoexcitation. Because of larger
   intermolecular distances in DTTOMe4, the photoluminescence is less
   effectively quenched by charge-transfer processes than in DTTOMe and


Boudaren, C   Auffredic, JP   Louer, M   Louer, D
A powder X-ray diffraction study of lead chloride oxalate Pb2Cl2(C2O4):
   ab initio structure determination and thermal behavior
POWDER DIFFRACTION 18, 2003, 205-213.
Mixed lead chloride oxalate, Pb2Cl2(C2O4), has been obtained in a
   polycrystalline form in the course of a study on precursors of
   nanocrystalline PZT-type oxides. Its crystal structure has been solved
   ab initio from powder diffraction data collected using a monochromatic
   radiation from a conventional X-ray source. The symmetry is monoclinic,
   space group C2/m, the cell dimensions are a = 5.9411(3) Angstrom, b =
   5.8714(4) Angstrom, c = 9.4212(4) Angstrom, beta = 95.232(4)degrees and
   Z = 2. The structure consists of a stacking of complex double sheets,
   built from lead polyhedra, parallel to (001) and connected together
   through oxalate groups. The lead atom is nine-fold coordinated by four
   0 atoms from one bidentate and two monodentate oxalate groups and five
   Cl atoms. The polyhedron can be described as a highly distorted square
   antiprism mono-capped by a Cl atom. The thermal behavior of lead
   chloride oxalate, in vacuum and in air, is carefully described from
   temperature-dependent powder diffraction and thermogravimetric
   measurements. It is shown that reaction pathways are complicated by the
   identification of various oxide chloride phases.

2003-44  ???

Barthelet, K   Adil, K   Millange, F   Serre, C   Riou, D   Ferey, G
Synthesis, structure determination and magnetic behaviour of the first
   porous hybrid oxyfluorinated vanado(III)carboxylate: MIL-71 or
   V-2(III)(OH)(2)F-2{O2C-C6H4-CO2} .  H2O
A new type of three-dimensional vanadium(III) dicarboxylate, MIL-71 or
   V-2(III)(OH)(2)F-2{O2C-C6H4-CO2}.H2O, has been obtained under
   hydrothermal conditions from aqueous mixtures of vanadium,
   1,4-benzenedicarboxylic acid, and HF. MIL-71cal or
   (V2O2F2)-O-IV{O2C-C6H4-CO2} is obtained by calcination of the parent
   compound in air at 250 degreesC. The three-dimensional structure of
   MIL-71 (S.G.: Cmmm; a = 21.4477(8) Angstrom, b = 7.1449(2) Angstrom, c
   = 3.8246(2) Angstrom, and Z = 2) consists of layers built from
   corner-sharing {(VO2)-O-III(OH)(2)F-2} octahedra connected by the
   terephthalate linkers. The role of fluorine in this structure is
   understood by comparison with the already known hybrid
   vanado(III)carboxylates. The thermal behavior of the two solids has
   been investigated using TGA and X-ray thermodiffractometry. Finally,
   magnetic measurements performed on both MIL-71 and MIL-71cal reveal a
   canted antiferromagnetic behavior with Neel temperatures below 20 K.


Corma, A   Rey, F   Valencia, S   Jorda, JL   Rius, J
A zeolite with interconnected 8-, 10- and 12-ring pores and its unique
   catalytic selectivity
NATURE MATERIALS 2, 2003, 493-497.
One of the major goals in catalysis is to improve the capabilities of
   microporous materials. This can be accomplished by synthesizing new
   zeolites; with controlled pore architectures. In particular, zeolites
   containing channels of different sizes in the same structure are
   desirable. Here, we report a zeolite containing fully interconnected
   8-, 10- and 12-membered-ring pores, synthesized by combining the
   structure-directing effect of the organic
   1,5-bis-(methylpyrrolidinium)-pentane and the framework isomorphic
   substitution of germanium for silicon. Analysis of the crystal
   structure determined by direct methods from synchrotron powder
   diffraction data reveals 16 independent tetrahedrally coordinated
   atoms. This thermally and hydrothermally stable zeolite structure, when
   synthesized in its acidic form by incorporating aluminium in the
   framework, presents unique catalytic shape-selectivity effects derived
   from its particular pore topology.


Stock, N   Guillou, N   Bein, T   Ferey, G
Inorganic-organic hybrid compounds: synthesis and crystal structure
   determination from powder diffraction data of Sn-2[O3PCH2C6H4CH2PO3]
SOLID STATE SCIENCES 5, 2003, 629-634.
A new tin diphosphonate, Sn-2[O3PCH2C6H4CH2PO3], was hydrothermally
   synthesized from alpha,alpha'-p-xylenediphosphonic acid and SnC2O4. The
   structure was solved and refined using X-ray powder diffraction data.
   It crystallizes in the triclinic space group P (1) over bar, with a =
   4.9659(3), b = 5.4916(3), c = 11.1730(6) Angstrom, alpha = 87.841(3),
   beta = 93.827(4), gamma = 90.652(3)degrees, V = 303.79(8) Angstrom(3),
   Z = 1, R-WP = 0.107, R-P = 0.081, R-B = 0.075, R-F = 0.056. The
   structure is built up from [SnO3] polyhedra, containing a
   stereochemically active lone pair of electrons. These polyhedra are
   connected to a ladder-like structure by phosphonate groups, RPO32-, and
   through the organic pact of the diphosphonic acid to a layered
   structure. Thermogravimetric and IR spectroscopic studies are also


Sanchez-Migallon, A   de la Hoz, A   Lopez, C   Claramunt, RM   Infantes, L
   Motherwell, S   Shankland, K   Nowell, H   Alkorta, I   Elguero, J
The structure of N-1-hydroxylophine N-3-oxide
   (=1-hydroxy-2,4,5-triphenyl-1H-imidazole 3-oxide) in the solid state
HELVETICA CHIMICA ACTA 86, 2003, 1026-1039.
The crystal structure of 1-hydroxy-2,4,5-triphenyl-1H-imidazole 3-oxide
   (1) has been determined from laboratory X-ray powder-diffraction data.
   The two independent molecules in the asymmetric unit form chains via
   O-H ... O hydrogen bonds related by a twofold screw axis. One of the O
   ... O distances is extremely short (2.32(1) and 2.43(1) Angstrom).
   Solid-state NMR spectroscopy (CPMAS) combined with calculation of
   absolute shieldings (GIAO/B3LW/6-31G*) allowed us to determine that the
   compound behaves as if the O-H ... O hydrogen bond has the proton in
   the middle (single-well potential), resulting in the near identity of
   both N-15-NMR signals.


Boudaren, C   Bataille, T   Auffredic, JP   Louer, D
Synthesis, structure determination from powder diffraction data and
   thermal behaviour of titanium(IV) oxalate [Ti2O3(H2O)(2)](C2O4)center
   dot H2O
SOLID STATE SCIENCES 5, 2003, 175-182.
A titanium(IV) oxalate, [Ti2O3(H2O)(2)](C2O4).H2O, has been synthesised
   in a polycrystalline form in the course of the study of precursors of
   PZT type oxides. Its crystal structure has been solved ab initio from
   powder diffraction data collected with conventional monochromatic
   X-rays. The symmetry is orthorhombic, space group Cmca, with cell
   dimensions a = 15.494(2) Angstrom, b = 10.491 (1) Angstrom, c =
   9.700(l) Angstrom and Z = 8. The structure consists of inorganic
   corrugated layers of corner-sharing TiO6 octahedra, which form infinite
   -Ti-O-Ti- connections, linked together by the oxalate anions. The
   titanium environment is discussed with regard to bond-valence
   calculations. The thermal behaviour of this compound has been studied
   by temperature-dependent X-ray diffraction and thermal analyses. In the
   course of the dehydration process, the partially dehydrated phase
   [Ti2O3(H2O)(2)](C2O4) has been isolated and its structure has been
   solved from in situ X-ray powder diffraction data. Its crystal
   structure determination has shown that the framework of the precursor
   is preserved. The complete decomposition scheme into anatase is also

2003-49  ??

Takata, M   Nishibori, E   Sakata, M   Wang, CR   Shinohara, H
Sc-2 dimer in IPR-violated C-66 fullerene: a covalent bonded
The structure of an IPR-violated metallofullerene Sc-2@C-66 has been
   determined in the electron density level by the MEM/Rietveld method
   using synchrotron radiation powder data. The fundamental structure has
   been obtained by the Rietveld analysis. The cage structure of C-66 has
   been unambiguously identified as that of Isomer No. 4348. The obtained
   charge density by the MEM analysis shows that the encapsulated two Sc
   atoms form the covalent bonded Sc-2 dimer and that the charge density
   of dimer is overlapping with that of C-66 cage, indicating the
   existence of a covalent bond character between Sc-2 and the carbon

2003-50 ??

Cacela, C   Baudot, A   Duarte, ML   Matos-Beja, AM
   Silva, MR   Paixao, JA   Fausto, R
Low temperature polymorphism in 3-amino-1-propanol
3-Amino-1-propanol (3AP) was investigated by differential scanning
   calorimetry, and low temperature powder X-ray diffraction and Raman
   spectroscopy. Within the range of temperatures studied (-150-25
   degreesC), 3AP was found to be able to crystallize in two monotropic
   polymorphs. Fast cooling rates produce an amorphous state that, on
   heating, crystallizes into the metastable polymorph. At higher
   temperatures, this metastable crystalline phase converts into the
   stable crystal. Using intermediate cooling rates, 3AP crystallizes as
   the metastable polymorph, the solid solid transition leading to
   conversion of this form into the stable polymorph occurring during the
   subsequent heating. Slower cooling rates enable formation of the stable
   crystal on cooling. The two crystalline polymorphs were structurally
   characterized by powder X-ray diffraction and Raman spectroscopy. It
   was concluded that different conformations are assumed by the
   individual molecules of 3AP in the two crystalline varieties, with the
   molecules assuming the all-trans configuration in the metastable
   crystalline state and having the heavy atom backbone trans but the NH2
   and OH groups gauche in the-stable crystal.


Barthelet, K   Riou, D   Nogues, M   Ferey, G
Synthesis, structure, and magnetic properties of two new
   vanadocarboxylates with three-dimensional hybrid frameworks
INORGANIC CHEMISTRY 42, 2003, 1739-1743.
(V-III(OH))(2){C6H2(CO2)(4)}.4H(2)O (labeled MIL-60) and
   VIII(OH){(2)(O2C)C6H2(COOH)(2)}.H2O (labeled MIL-61) were
   hydrothermally synthesized from mixtures of VCl3,
   1,2,4,5-benzenetetracarboxylic acid, and water heated for 3 days at 473
   K The structure of MIL-60 was solved from single-crystal X-ray
   diffraction data in the triclinic centrosymmetric P1 (No. 2) space
   group with lattice parameters a = 6.3758(5) Angstrom, b = 6.8840(5)
   Angstrom, c = 9.0254(5) Angstrom, alpha = 69.010(2)degrees, beta =
   85.197(2)degrees, gamma = 79.452(2)degrees, V = 363.53(5) Angstrom(3),
   and Z = 1. The structure of MIL-61 was ab initio determined from an
   X-ray powder diffraction pattern. MIL-61 crystallizes in the Pnma (No.
   62) orthorhombic space group with lattice parameters a = 14.8860(1)
   Angstrom, b = 6.9164(l) Angstrom, c =10.6669(2) Angstrom, V =
   1098.23(3) Angstrom(3), and Z = 4. Both structures contain the same
   inorganic building block that consists of trans chains Of
   (VO4)-O-III(OH)(2) octahedra. The three-dimensional frameworks of
   MIL-60 and MIL-61 are constituted by the linkage of these chains via
   the organic molecules so delimiting the channels or cages where the
   water molecules are encapsulated. The magnetic behavior of these two
   phases is presented: MIL-60 is paramagnetic, and MIL-61
   antiferromagnetically orders below T-N = 55(5) K.


Guillou, N   Livage, C   van Beek, W   Nogues, M   Ferey, G
A layered nickel succinate with unprecedented hexanickel units:
   Structure elucidation from powder-diffraction data, and magnetic and
   sorption properties


Ma, HA   Jia, X   Cui, QL   Pan, YW   Zhu, PW   Liu, BB
   Liu, HJ   Wang, XC   Liu, J   Zou, GT
Crystal structures of C3N6H6 under high pressure
CHEMICAL PHYSICS LETTERS 368, 2003, 668-672.
In situ high-pressure energy-dispersive X-ray diffraction (EDXRD)
   experiments on melamine (C3N6H6) have been carried out using diamond
   anvil cell (DAC) with synchrotron radiation source. In the pressure
   range from ambient pressure up to 14.7 GPa, two pressure-induced
   structure phase transitions, from monoclinic to triclinic structure at
   about 1.3 GPa and from triclinic to orthorhombic structure at about 8.2
   GPa, are observed. The crystal structures of melamine at different
   pressures are built by using Materials Studio (MS) based on the
   principle of energy minimization.


Khan, MS   Al-Mandhary, MRA   Al-Suti, MK   Corcoran, TC   Al-Mahrooqi, Y
   Attfield, JP   Feeder, N   David, WIF   Shankland, K   Friend, RH
   Kohler, A   Marseglia, EA   Tedesco, E   Tang, CC   Raithby, PR
   Collings, JC   Roscoe, KP   Batsanov, AS   Stimson, LM   Marder, TB
Synthesis and optical characterisation of platinum(II) poly-yne
   polymers incorporating substituted 1,4-diethynylbenzene derivatives and
   an investigation of the intermolecular interactions in the
   diethynylbenzene molecular precursors
NEW JOURNAL OF CHEMISTRY 27, 2003, 140-149.
A series of 1,4-diethynylbenzene (1) derivatives, H-Cequivalent
   toC-R-Cequivalent toC-H with R=C6H3NH2 (2), C6H3F(3), C6H2F2-2,5 (4),
   C6F4 (5), C6H2(OCH3)(2)-2,5 (6) and C6H2 ((OC8H17)-C-n)(2)-2,5 (7) has
   been synthesised and their crystal structures determined by single
   crystal (2-5) or powder (6, 7) X-ray diffraction. The Cequivalent
   toCH...pi(Cequivalent toC) hydrogen bonds dominating structure 1 are
   gradually replaced by Cequivalent toC-H...F ones with the increase of
   fluorination (3-->5), or completely replaced by Cequivalent toCH...N
   and NH...pi(Cequivalent toC) bonds in 2, and Cequivalent toCH...O in 6
   and 7. The related platinum-based polymers,
   trans-[Pt((PBu3)-Bu-n)(2)-Cequivalent toC-R-Cequivalent toC-](n) (R=as
   above and C6H4,) have been prepared and characterised by spectroscopic
   methods and thermogravimetry, which show that the amino- and
   methoxy-derivatives have lowest thermal stability while the fluorinated
   ones exhibit increasing thermal stability with increasing fluorination.
   Optical spectroscopic measurements reveal that substituents on the
   aromatic spacer group do not create strong donor-acceptor interactions
   along the rigid backbone of the organometallic polymers.


Nockemann, P   Cremer, U   Ruschewitz, U   Meyer, G
Mercurous azide, Hg-2(N-3)(2)
White polycrystalline mercurous azide, Hg-2(N-3)(2), is obtained by
   combining aqueous solutions of NaN3 and Hg-2(NO3)(2).2H(2)O (made
   viscuous by addition of tetramethoxysilane and heating at 65 degreesC).
   The crystal structure was solved and refined from X-ray powder
   diffraction data (monoclinic, P2(1)/n, a = 596.07(2) pm, b = 1259.07(4)
   pm, c = 357.95(1) pm, beta 103.253(2)degrees, Z = 2, R-B = 0.0519).
   Solid Hg-2(N-3)(2) contains, essentially, molecules of that composition
   with Hg-Hg distances of 254.4(3) pm, Hg-N distances of 218(2) pm and
   Hg-Hg-N angles of 178.7(6)degrees. Weak intermolecular interactions
   with Hg-N distances starting at 280(3) pm lead to a three-dimensional


Nalini, G   Subbanna, GN   Row, TNG
Studies on n=2 Aurivillius phases: structure of the series
   Bi3-xLaxTiNbO9 (0 <= x <= 1)
The crystal structures of the solid solutions of Bi3-xLaxTiNbO9 (0 less
   than or equal to x less than or equal to 1) have been analyzed by
   powder X-ray diffraction with supporting evidence from selected area
   electron diffraction (SAD). The structure of the starting member (x =
   0) is verified to be in the orthorhombic space group A2(1) am while the
   end member (x = 1) is determined to crystallize in the centrosymmetric
   orthorhombic space group Pmcb. The structure of x = 1 phase is solved
   by ab initio powder diffraction. The intermediate compositions belong
   to the space group A2(1) am as confirmed by Rietveld refinements.
   Rietveld refinements on all the compositions reveal that the La3+ ion
   is disordered only in the A site and not in the [Bi2O2](2+) layer. The
   tilt in the Ti/NbO6 octahedra decreases with increasing x.

2003-57   ???

Ju, J   Lin, JH   Li, GB   Yang, T   Li, HM   Liao, FH   Loong, CK   You, LP
Aluminoborate-based molecular sieves with 18-octahedral-atom tunnels

2003-58   ???

AU Yebra-Rodriguez, A   Martin-Ramos, JD   del Rey, F   Viseras, C   Lopez-Galindo, A
Effect of acid treatment on the structure of sepiolite
CLAY MINERALS 38, 2003, 353-360.
An ab initio determination of the structure of sepiolite after acid
   treatment (HCI 0.5 N for 24 h) was carried out using X-ray powder
   diffraction data. After acid treatment, the sections normal to the a
   and c axes presented discontinuities, similar to2.25 Angstrom wide,
   parallel to the (0 10) plane, with no electronic density maxima, thus
   suggesting that adjacent planes are joined by van der Waals-like
   residual links. Partial dissolution was detected oil both octahedral
   and tetrahedral sheets, beginning by breaking the ribbons not along the
   edges, but in the centre, thus creating a 5.20 x 6.79 Angstrom tunnel
   along the a axis. By interrupting the tetrahedral sheet, this mechanism
   changes the phyllosilicate-like nature of the sepiolite to an
   inosilicate-like structure.

2003-59  ???

Plevert, J   Sanchez-Smith, R   Gentz, TM   Li, HL   Groy, TL
   Yaghi, OM   O'Keeffe, M
Synthesis and characterization of zirconogermanates
INORGANIC CHEMISTRY 42, 2003, 5954-5959.
Six new zirconogermanates have been prepared under hydrothermal
   conditions using amines as bases. There are four new structure types
   (ASU-n) with a common motif of ZrGe5. ASU-23 is a layered structure:
   ZrGe3O8(OH)F.[C10H26N4].H2O, space group P2(1)/n, a = 6.7957(8)
   Angstrom, b = 12.700(1) Angstrom, c = 24.293(3) Angstrom, beta =
   97.936(2)degrees, V = 2076.4(4) Angstrom(3). ASU-24 is a pillared
   layered structure:
   Zr3Ge6O18(OH2,F)(4)F-2.[C6H18N2](2).[C6H17N2](2).2H(2)O, space group
   P2(1)/n, a = 7.4249(3) Angstrom, b = 25.198(1) Angstrom, c = 11.3483(5)
   Angstrom, beta = 90.995(1)degrees, V = 2122.9(2) Angstrom(3). This
   material has the lowest framework density (FD) of any oxide material
   that we are aware of (FD = 8.48 metal atoms/nm(3)). Two other materials
   form three-dimensional open-frameworks, ASU-25: ZrGe3O9.[C3H12N2],
   space group P112(1)/a, a = 13.1994(4) Angstrom, b = 7.6828(2) Angstrom,
   c = 11.2373(3) Angstrom, gamma = 91.233(3)degrees, V = 1139.29(5)
   Angstrom(3). The other is ASU-26: ZrGe3O9.[C2H10N2], space group Pn, a
   = 13.7611(3) Angstrom, b = 7.7294(2) Angstrom, c = 11.2331(3) Angstrom,
   beta = 104.793(1)degrees, V = 1155.21(4) Angstrom(3). ASU-25 is related
   to the mineral umbite K2ZrSi3O9.H2O. The germanium equivalent has been
   prepared through the inorganic route: K2ZrGe3O9.H2O, space group
   P2(1)2(1)2(1), a = 13.6432(6) Angstrom, b = 7.4256(3) Angstrom, c =
   10.3973(4) Angstrom, V = 1053.33(8) Angstrom(3). The structural
   relationships between ASU-25 and its inorganic counterpart are
   described. The thermal decomposition of the germanium umbite generated
   the cyclic trigermanate K2ZrGe3O9, analogue of the mineral wadeite,
   crystallizing in the orthorhombic system, a = 7.076 Angstrom, b =
   12.123 Angstrom, c = 10.451 Angstrom, V = 904.5 Angstrom(3).


Crossland, CJ   Evans, JSO
Synthesis and characterisation of a new high pressure polymorph of
CHEMICAL COMMUNICATIONS iss 18, 2003, 2292-2293.
In this communication we report the synthesis and structural
   characterisation of a new body centred polymorph of Cu2WS4 prepared
   using hydrothermal methods. I-Cu2WS4 crystallises in space group I (4)
   over bar 2m with cell parameters a = b = 5.44427(8), c = 10.0687(2)
   Angstrom and has a new structure type containing layers of edge-sharing
   CuS4 and WS4 tetrahedra.


Migdal-Mikuli, A   Mikuli, E   Hetmanczyk, L   Natkaniec, I
   Holderna-Natkaniec, K   Lasocha, W
Phase transitions, structural changes and molecular motions in
   [Zn(NH3)(4)](BF4)(2) studied by neutron scattering, X-ray powder
   diffraction and nuclear magnetic resonance
Nuclear magnetic resonance (H-1 NMR and F-19 NMR) measurements
   performed at 90-295K, inelastic incoherent neutron scattering (IINS)
   spectra and neutron powder diffraction (NPD) patterns registered at
   22-190 K, and X-ray powder diffraction (XRPD) measurements performed at
   86-293 K, provided evidence that the crystal of [Zn(NH3)(4)](BF4)(2)
   has four solid phases. The phase transitions occurring at: T-C3 = 101
   K, T-C2 = 117 K and T-C1 = 178 K, as were detected earlier by
   differential scanning calorimetry (DSC), were connected on one hand
   only with an insignificant change in the crystal structure and on the
   other hand with a drastic change in the speed of the anisotropic,
   uniaxial reorientational motions of the NH3 ligands and BF4- anions (at
   T-C3 and at T-C2) and with the dynamical orientational order-disorder
   process ("tumbling") of tetrahedral [Zn(NH3)(4)](2+) and BF4- ions (at
   T-C1). The crystal structure of [Zn(NH3)(4)](BF4)(2) at room
   temperature was determined by XRPD as orthorhombic, space group Pnma
   (No. 62), a = 10.523 Angstrom, b 7.892 Angstrom, c = 13.354 Angstrom
   and Z = 4. Unfortunately, it was not possible to determine the
   structure of the intermediate and the low-temperature phase. However,
   we registered the change of the lattice parameters and unit cell volume
   as a function of temperature and we can observe only a small deviation
   from near linear dependence of these parameters upon temperature in the
   vicinity of the T-C1 phase transition.


Kiang, YH   Huq, A   Stephens, PW   Xu, W
Structure determination of enalapril maleate Form II from
   high-resolution X-ray powder diffraction data
The crystal structure of polymorphic Form II of enalapril maleate, a
   potent angiotensin-converting enzyme inhibitor, was determined from
   high-resolution X-ray diffraction data using the direct space method.
   Enalapril maleate Form II crystallizes in space group P2(1)2(1)2(1), Z
   = 4, with unit cell parameters a = 33.9898(3) Angstrom, b = 11.2109(1)
   Angstrom, c = 6.64195(7) Angstrom, and V = 2530.96(5) Angstrom(3). By
   treating the molecules as rigid bodies and using the bond lengths and
   angles obtained from the X-ray single crystal structures of Form I,
   which were solved almost 20 years ago, the total degrees of freedom of
   enalapril maleate were reduced from 25 to 12. This reduction in total
   degrees of freedom allowed the simulated annealing to complete within a
   reasonable computation time. In the crystal structure of Form II, the
   crystal packing, hydrogen-bonding pattern, and conformation of
   enalapril maleate resemble those in the structure of Form I. The
   crystal packing and conformation of enalapril maleate in the two
   polymorphic forms may explain the similarity of the thermal properties,
   C-13 nuclear magnetic resonance, Fourier transform infrared, and Raman
   spectra of Forms I and II. In both structures, the conformations of the
   main peptide chains, which are considered responsible for binding the
   active angiotensin-converting enzyme sites, remain largely unchanged.
   Lattice energy calculation showed that Form 11 is slightly more stable
   than Form I by 3.5 kcal/mole.


Evans, IR   Howard, JAK   Evans, JSO
alpha-Bi2Sn2O7 - a 176 atom crystal structure from powder diffraction
Pyrochlore-type bismuth tin oxide, Bi2Sn2O7, is a technologically
   important material used in applications such as catalysis and gas
   sensing. Its room temperature structure has been solved by a method of
   simulated annealing of combined X-ray and neutron diffraction data,
   followed by Rietveld refinement. With 176 crystallographically
   independent atoms in the asymmetric unit, it is one of the largest
   structures solved to-date from powder diffraction data. In addition to
   the number of unique atoms, additional crystallographic difficulty
   stems from the fact that the true symmetry of this structure is lower
   than the apparent metric symmetry of the unit cell.


Irran, E   Bein, T   Stock, N
Inorganic-organic hybrid materials: synthesis and crystal structure
   determination from powder diffraction data of Pb-2(O3PCH2C6H4CH2PO3)
A new lead diphosphonate, Pb-2(O3PCH2C6H4CH2PO3) was hydrothermally
   synthesized from tetraethyl alpha,alpha'-p-xylenediphosphonate and
   Pb(NO3)(2). The structure was solved and refined using X-ray powder
   diffraction data. It crystallizes in the monoclinic space group
   P2(1)/c, with a = 467.84(2), b = 2007.98(9), c = 639.10(2) pm, beta =
   101.020(3)degrees, V = 589.31(4) 10(6) pm, Z = 2 wR(p) = 0.034, R-p =
   0.0277 R(F)2 = 0.061, R-F = 0.036. The structure is built from
   corner-linked [PbO4] polyhedra, containing a lone pair of electrons.
   These polyhedra are connected to layers by phosphonate groups, RPO32-
   and through the organic diphosphonic acid to a three-dimensional
   structure. Thermogravimetric as well as IR spectroscopic studies are
   also presented.


Paul-Boncour, V   Filipek, SM   Marchuk, I   Andre, G
   Bouree, F   Wiesinger, G   Percheron-Guegan, A
Structural and magnetic properties of ErFe2D5 studied by neutron
   diffraction and Mossbauer spectroscopy
A neutron powder diffraction study of ErFe2D5, synthesized under 1 GPa
   hydrogen pressure, shows that it crystallizes at room temperature in an
   orthorhombic structure described by the Pmn2(1) space group with a =
   5.42 Angstrom, b = 5.79 Angstrom, c = 8.00 Angstrom. The deuterium
   atoms order preferentially in some A(2)B(2) and AB(3) interstitial
   sites. Below 5 K the erbium moments order in a canted magnetic
   structure, with an erbium moment of 6.6 mu(B) at 1.4 K. The Fe-57
   Mossbauer spectra of ErFe2D5 from 4.2 to 300 K indicate that there are
   no ordered Fe moments at zero field. These results are discussed in
   relation to the influence of hydrogen absorption on the magnetic

Dinnebier, RE   Carlson, S   Hanfland, M   Jansen, M
Bulk moduli and high-pressure crystal structures of minium, Pb3O4,
   determined by X-ray powder diffraction
AMERICAN MINERALOGIST 88, 2003, 996-1002.
We report the pressure dependence of the crystal structure of lead
   tetroxide (P less than or equal to 41.05 GPa, T 298 K) using
   high-resolution angle-dispersive X-ray powder diffraction. Pb3O4 shows
   two reversible phase transitions in the measured pressure range. The
   crystal structures of the modifications identified have in common
   frameworks of Pb+4O6 octahedra and irregular Pb+2O4+1 respectively
   Pb2+O6+1 polyhedra. At ambient conditions, Pb3O4 crystallizes in space
   group P4(2)/mbc (phase 1). Between 0.11 and 0.3 GPa it exhibits a
   displacive second order phase transition to a structure with space
   group Pbam (phase II). A second displacive phase transition occurs
   between 5.54 and 6.6 GPa to another structure with space group Pbam
   (phase 111) but halved c dimension. A non-linear compression behavior
   over the entire pressure range is observed, which can be described by
   two Vinet relations in the ranges from 0.28 to 5.54 GPa and from 6.6 to
   41.05 GPa. The extrapolated bulk moduli of the high-pressure phases
   were determined to be K-0 = 21(2) GPa for phase 11 and K-0 = 91(3) GPa
   for phase III. The crystal structures of all phases were refined from
   X-ray diffraction powder data collected at several pressures between
   0.06 and 41.05 GPa. Except for their cell dimensions, phases I and 11
   were found to be isostructural to the corresponding phases at low
   temperatures, whereas phase III can be derived from the Sr2PbO4
   aristotype. With increasing pressure, the lone pair which is localized
   at Pb2+ adopts increasingly pure s-character, which is reflected by the
   similar coordination polyhedra of Ph2+ in Pb3O4 (phase 111) and of Sr2+
   in Sr2PbO4.

2003-67   ????

Habereder, T     Noth, H
Chemistry of boron, part 250 - 2-Triorgano-silyl, -germyl, -stannyl and
   -plumbyl derivatives of 1,3-diisopropyl-benzo-1,3,2-diazaborolidine and
   related compounds and their reactions with (eta(2)-C2H4)Pt(PPh3)(2)
A series of 1,3-diisopropyl-benzo-1,3,2-diazaborolidines 1-6 carrying
   ER3 substituents of Group 14 at the boron atom (E = C, Si, Ge, Sn, Pb;
   R = Me, Ph) have been prepared. Their molecular structures have been
   determined. As expected, the B-E bond length increases along this
   series. Moreover, the orientation of the isopropyl groups relative to
   the ER3 substituent is influenced by the steric demand of these
   substituents. The B-11 NMR data show a deshielding of the boron nucleus
   as the atomic weight of E increases. Oxidative addition reactions with
   (eta(2)-C2H4)Pt(PPh3)(2) were successful only for the bromo derivative
   I and the trimethylstannyl derivative 5a, they failed for the
   triphenylsilyl, triphenylgermyl. and triphenylstannyl compounds,
   indicating that steric effects play an important role in the successful
   oxidative addition to boryl-substituted
   bis(triphenylphosphane)platinum(II) complexes. The triphenylplumbyl
   derivative 6 reacted with (eta(2)-C2H4)Pt(PPh3)(2) to give cis- and
   trans-diphenyl-bis(triphenylphosphane)platinum besides
   Ph(Ph3Pb)Pt(PPh3)(2). Obviously, the Pb-C bond is more reactive than
   the Pb-B bond. Cis-Platinum-boryl complexes were also obtained from
   (Me2N)(2)B-SnMe3 and (Me2N)(2)B-GeMe3 while the boranes tmpB(SnMe3)(2)
   and (Pr2NB)-Pr-i(SnMe3)(2) were unreactive.


Li, LY   Jin, XL   Li, GB   Wang, YX   Liao, FH   Yao, GQ   Lin, JH
Novel rare earth polyborates. 2. Syntheses and structures
CHEMISTRY OF MATERIALS 15, 2003, 2253-2260.
Three novel hydrated rare earth polyborates, Ln[B8O11(OH)(5)] (Ln =
   La-Nd) (1), Ln[B9O13-(OH)(4)].H2O (Ln = Pr - Eu) (2), and
   Ce[B5O8(OH)]NO3.3H(2)O (3) have been synthesized by using boric acid as
   a flux at 240 degreesC, starting from rare earth oxides or nitrates and
   an excess of boric acid. All these polyborates crystallize in
   monoclinic structures (P2(1)/n) and consist of borate sheets as the
   fundamental unit, that is, [LnB(6)O(11)] sheet in 1 and 2 and [CeB5O9]
   sheet in 3. The borate sheets all contain a nine-membered borate ring,
   of which the rare earth cations are located around the center. The
   borate frameworks in 1 and 3 are two-dimensional, which are interlinked
   via ionic Ln-O bonds forming 3D structures. While in 2 the borate
   framework is three-dimensional with small channels filled by water
   molecules. Annealing the hydrated polyborates I and 2 at moderate
   temperature leads to two anhydrous pentaborates, alpha-LnB(5)O(9) (4)
   for Ln = Pr-Eu and beta-LnB(5)O(9) (5) for Ln = La, Ce. The structure
   of beta-LaB5O9 has been determined by an ab initio method using powder
   X-ray diffraction data. It crystallizes in a monoclinic structure in
   the space group P2(1)/c with a = 6.4418(l) Angstrom, b = 11.6888(3)
   Angstrom, c = 8.1706(2) Angstrom, and beta = 105.167(1)degrees. The
   structure of beta-LnB(5)O(9) contains buckled nine-membered ring borate
   sheets that are interlinked by BO3 groups forming a three-dimensional
   framework. The Eu3+-doped beta-LaB5O9 materials show dominant D-5(0
   -->) F-7(2) emission and a low quenching concentration (0.6 at. %).


Park, H   Barbier, J   Hammond, RP
Crystal structure and polymorphism of PbAlBO4
SOLID STATE SCIENCES 5, 2003, 565-571.
Two polymorphs of the new borate compound, PbAlBO4, have been
   synthesized in microcrystalline form and their crystal structures have
   been refined from powder neutron diffraction data. The low-temperature
   form, alpha-PbAlBO4, crystallizes in the Pnma space group with a =
   6.9209(5) Angstrom, b = 5.7134(4) Angstrom, c = 8.0215(6) Angstrom, Z =
   4. Its structure is built of straight [010] chains of edge-shared AlO6
   octahedra bridged by BO3 groups and Pb2+ cations. The high-temperature
   form, beta-PbAlBO4, is obtained by heating the a form to 1048 K
   followed by quenching in air. It crystallizes in the Pbcn space group
   with a = 7.0423(3) Angstrom, b = 9.8989(3) Angstrom, c = 9.4281(3)
   Angstrom, Z = 8. The structure of beta-PbAlBO4 contains zig-zag chains
   of AlO6 octahedra bridged by BO3 groups and Pb2+ cations and is related
   to the structure of alpha-PbAlBO4 by unit-cell twinning. The detailed
   crystal chemical analysis of the alpha- and beta-PbAlBO4 structures
   shows that the alpha-->beta transformation is driven by a decrease in
   density and the relief of bonding and non-bonding, interactions around
   the Pb2+ cations.


Brunelli, M   Wright, JP   Vaughan, GRM   Mora, AJ   Fitch, AN
Solving larger molecular crystal structures from powder diffraction
   data by exploiting anisotropic thermal expansion


Brinks, HW   Hauback, BC
The structure of Li3AlD6
The structure of Li3AlD6 has been determined by combined synchrotron
   X-ray and neutron diffraction. The space group is R3 with unit-cell
   dimensions a = 8.07117(10) and c = 9.5130(2) Angstrom. The structure
   consists of isolated and close to regular AlD63- octahedra, which are
   connected via six-coordinated Li. The Al-D distances are 1.734-1.754
   Angstrom, and the Li-D distances are 1.892-2.120 Angstrom. The shortest
   D-D distance of 2.395 Angstrom is found within the octahedra. The
   structure can be described as a distorted bcc structure of AlD63- units
   with all tetrahedral sites filled with Li.


AU Kongshaug, KO   Fjellvag, H
Novel coordination polymers based on nickel(II) and
SOLID STATE SCIENCES 5, 2003, 303-310.
The two coordination polymers [Ni(ndc)(lutidine)(2)(H2O)(2)], CPO-3,
   and [Ni-3(ndc)(3)(pyridine)(4)], CPO-4, were obtained by hydrothermal
   reactions between 2,6-naphthalenedicarboxylic acid (ndc), 3,4-lutidine
   and nickel(II) nitrate (CPO-3) and ndc, pyridine and nickel(II) nitrate
   (CPO-4), respectively. In CPO-3, the combination of octahedral
   nickel(II) ions and ndc ligands leads to the formation of infinite
   chains. CPO-4 is based on linear trinuclear building units of
   octahedral nickel(II) ions that are crosslinked via the ndc ligands to
   form a 3D-structure. The crystal structure of CPO-3 was solved from
   synchrotron powder X-ray data, while the crystal structure of CPO-4 was
   solved from conventional single-crystal X-ray data. Crystal data for
   CPO-3: monoclinic space group Cc (No. 9), a = 14.8583(2), b =
   20.3985(3), c = 10.7258(1) Angstrom, beta = 129.0067(6)degrees, V =
   2526.14(5) Angstrom(3) and Z = 4. Crystal data for CPO-4: monoclinic
   space group P2(1)/c (No. 14), a = 11.491(3), b = 17.917(4), c =
   12.781(3) Angstrom, beta = 116.142(7)degrees, V = 2362.2(9) Angstrom(3)
   and Z = 2. The thermal and magnetic properties of both compounds were


Renaudin, G   Bertheville, B   Yvon, K
Synthesis and structure of an orthorhombic low-pressure polymorph of
   caesium magnesium hydride, CsMgH3
CsMgH3 was synthesized by heating mixtures of the binary hydrides in an
   autoclave at 600 K and a hydrogen pressure of 150 bars. Synchrotron
   X-ray and neutron powder diffraction reveals a new structure having
   orthorhombic symmetry (space group Pmmn, a = 9.9958(1), b = 6.13271(6),
   c = 8.57364(9) Angstrom for the hydride). In contrast to the trigonal
   high-pressure polymorph, magnesium centred [MgH6] octahedrons are
   condensed into triangular rather than linear [3MgH(3)](3-) trimers, and
   these trimers are connected via four corners to two-dimensional slabs
   rather than via six corners to a three-dimensional network. The Mg-D
   distances in the deuteride range from 1.94 to 1.96 Angstrom at the
   periphery to 2.00-2.08 Angstrom at the centre of the trimers. The Mg
   displacements within the octahedrons suggest repulsive Mg2+-Mg2+


Harvey, HG   Teat, SJ   Tang, CC   Cranswick, LM   Attfield, MP
Synthesis and characterization of three novel cation-containing
   (NH4+/(CHNH3+)-H-3-N-7/NH3+C2H4NH3+) aluminum diphosphonates
INORGANIC CHEMISTRY 42, 2003, 2428-2439.
Three new aluminum diphosphonates (C3H7NH3){AIF[(HO)O2PC2H4PO3]} (1)
   (orthorhombic, Pnma, a = 8.2048(l) Angstrom, b = 6.90056(6) Angstrom, c
   = 19.6598(4) Angstrom, Z = 4), (H3NC2H4NH3)[AI(OH)(O3PC2H4PO3)] (2)
   (monoclinic, P2(1)/n, a = 11.142(3) Angstrom, b = 7.008(2) Angstrom, c
   = 12.903(5) Angstrom, = 96,24(7)degrees, Z = 4), and
   (NH4)2[AIF(O3PCH2PO3)](3) (orthorhombic, Cmcm, a = 16.592(2) Angstrom,
   b = 7.5106(g) Angstrom, c = 7.0021 (9) Angstrom, Z = 4) have been
   synthesized by solvothermal methods in the presence of linear organic
   ammonium cations (for 1 and 2) and ammonium cations (for 3) and their
   structures determined using powder, microcrystal, and single-crystal
   X-ray diffraction data, respectively. All three materials contain a
   similar one-dimensional chain motif which is related to that found in
   the mineral Tancoite. This chain motif consists of corner-sharing
   octahedra (AIO(4)F(2) for 1 and 3 and AIO(6) for 2) linked together
   through the bridging CPO3 tetrahedra of the diphosphonate groups. These
   chains are unusual in that each diphosphonate moiety acts as a
   bisbidentate ligand that is coordinated to the same two metal centers
   through both of the O3PC-groups of the diphosphonate ligand. The
   arrangement of the Tancoite-like chains and charge compensation cations
   in the structures of compounds 1-3 is seen to be dependent upon the
   nature of the diphosphonic acid and organoammonium/ammonium cations.
   Careful selection of these two components may provide a method to
   design future materials in this system.

2003-75   ?????

Jeong, HK   Nair, S   Vogt, T   Dickinson, LC   Tsapatsis, M
A highly crystalline layered silicate with three-dimensionally
   microporous layers
NATURE MATERIALS 2, 2003, 53-58.
Layered silicates with three-dimensional microporosity within the
   layers have the potential to enable new applications in catalysis,
   adsorption and ion-exchange. Until now no such materials have been
   reported. However, here we present the synthesis and structure of
   AMH-3, a silicate with three-dimensionally microporous layers, obtained
   in high purity and crystallinity. AMH-3 is composed of silicate layers
   containing eight-membered rings in all three principal crystal
   directions, and spaced by strontium cations, sodium cations and water
   molecules. Because of its three-dimensional pore structure, acid and
   thermal stability, this layered material could find applications in
   polymer-silicate composites for membrane applications, for synthesis of
   combined microporous-mesoporous materials, and for the formation of new
   zeolites and microporous films. Its existence also opens new
   possibilities for the synthesis of other layered silicates with
   multidimensional microporous framework layers.
AMH-3, Na8 Sr8 Si32 O76 .16 H2 O, C2/c, conventtional X-ray + synchrotron
No program name given for indexation, EXPO for "|Fobs|" extraction (Le Bail
method), EXPO for direct methods, locating all one Sr and four Si atoms (5 of a
total of 19 independent atoms), completion by alternating Rietveld and Fourier
difference using GSAS on the synchrotron data


Plevert, J   Gentz, TM   Groy, TL   O'Keeffe, M   Yaghi, OM
Layered structures constructed from new linkages of Ge-7(O,OH,F)(19)
CHEMISTRY OF MATERIALS 15, 2003, 714-718.
Three new germanate solids, ASU-19, ASU-20-DAPe, and ASU-20-DACH, have
   been synthesized under hydrothermal conditions using respectively
   1,4-diaminobutane (DAB), 1,5-diaminopentane (DAPe), and
   1,4-diaminocyclohexane (DACH) as bases. The structures of ASU-19 and
   ASU-20-DACH have been characterized by single-crystal X-ray
   diffraction: ASU-19, Ge14O29X4.[GeOX2].[H(2)DAB](3).3.8H(2)O (X = F or
   OH), space group P (1) over bar, a = 11.4191(5), b = 12.05250, c =
   18.1847(8) Angstrom, alpha = 90.704(1)degrees, beta = 92.635(1)degrees,
   gamma = 91.389(1)degrees, V = 2499.1(2) Angstrom(3); ASU-20-DACH:
   Ge7O14X3.[H(2)DACH](1.5).2H(2)O, space group C2/c, a = 15.9525(11), b =
   17.5476(12), c = 19.0027(13) Angstrom, beta = 109.446(1)degrees, and V
   = 5015.90 Angstrom(3). The structure of ASU-20-DAPe,
   Ge7O14X3.[H(2)DAPe](1.5).H2O, has been determined from X-ray powder
   diffraction data: space group C2/c, a = 16.3180(5), b = 16.6125(4), c =
   17.8898(6) Angstrom, beta = 99.684(2)degrees, V = 4780.5(3)
   Angstrom(3). All three structures are based on the assembly of the same
   cluster Ge-7(O,OH,F)(19). The two ASU-20 structures consist of a slab
   of four-connected clusters. In ASU-19, the same layers are connected
   pairwise through a GeO2X2 spacer, generating a slab structure, with
   slab thickness ca. 20 Angstrom. The existence of the same layer in the
   presence of three different organic bases shows the adaptability of the
   structures to molecules differing in size, shape, and symmetry.


Bie, LJ   Wang, YX   Lin, JH   Loong, CK   Richardson, JW
   You, LP   Dong, C
Synthesis and structure of n=5 member of the A(n+1)Mn(n)O(3n+3)(A(2)O)
CHEMISTRY OF MATERIALS 15, 2003, 516-522.
La4Ba2.6Ca1.4(Mn4Ca)O-19, a novel hexagonal perovskite-intergrowth
   manganate, was synthesized by solid-state reaction. It crystallizes in
   the space group C2/m (no. 12) with the lattice parameters of a =
   9.8394(4) Angstrom, b = 5.6823(2) Angstrom, c = 15.6435(3) Angstrom,
   and beta = 102.093(5), cell volume of 855.21(5) Angstrom(3), and Z = 2.
   The structure was investigated by electron, X-ray, and neutron
   diffraction techniques and fully resolved by refinements of both X-ray
   and neutron powder diffraction data. The structure can be described as
   alternate stacking of 6H-type hexagonal perovskite blocks and
   graphite-like Ca2O sheets. In the hexagonal perovskite block, Mn and Ca
   cations occupy the octahedral sites of the corner-shearing and
   face-shearing octahedra, respectively. Preferred La/Ba and Ca/La
   substitution at the ratio of 7:3 was observed over specific
   crystallographic sites. La(4)Ba(2.6)Cal(1.4)(Mn4Ca)O-19 is an n = 5
   member of the A(n+1)Mn(n)O(3n+3)(Ca2O) series in which 1/5 of the Mn
   atoms in the 6H-hexagonal perovskite blocks are replaced by Ca. A
   structural principle that is based on alternate stacking of
   close-packed [AO(3)] layers and graphite-like sheets is introduced for
   structural prediction of new hexagonal perovskite intergrowth compounds.


Dinnebier, RE   Vensky, S   Jansen, M
Crystal and molecular structure of rubidium peroxodicarbonate Rb-2[C2O6]
We report the crystal structure of rubidium peroxodicarbonate, which
   was synthesized by electrocrystallization at T = 257 K, from laboratory
   X-ray powder diffraction data. The compound crystallizes in the
   monoclinic space group P2(1)/c with four formula units per unit cell
   and cell parameters of a=7.9129(1), b=10.5117(1), c=7.5559(1) Angstrom,
   beta=102.001(1)degrees, and V=614.75(1) Angstrom(3). The packing can be
   considered as a strongly distorted CsCl type of structure. The
   conformation of the peroxodicarbonate anion was found to be planar
   (C-2h symmetry), in contrast to the staggered conformation of the
   peroxodicarbonate anion in the respective potassium peroxodicarbonate.
   ne different conformation is attributed to packing effects.


Botez, CE   Stephens, PW   Nunes, C   Suryanarayanan, R
Crystal structure of anhydrous delta-D-mannitol
POWDER DIFFRACTION 18, 2003, 214-218.
The crystal structure of anhydrous delta-D-mannitol (C6H14O6) was
   solved from high-resolution synchrotron X-ray powder diffraction data
   collected on a mixture containing 20% and 80% w/w of beta- and
   delta-D-mannitol, respectively. The direct space simulated annealing
   program PSSP, and Rietveld analysis employing GSAS were used to
   determine and refine the structure. The polymorph has monoclinic
   symmetry, space group P2(1) with a = 5.089 41(5) Angstrom, b =
   18.2504(2) Angstrom, c = 4.917 02(5) Angstrom, and beta =
   118.303(2)degrees. There is one molecule in the irreducible volume of
   the unit cell. The pattern of hydrogen bonding is significantly
   different than the previously known a and 8 forms.


Friese, K   Honnerscheid, A   Jansen, M
Crystal structure determination of systematically intergrown compounds:
   Li-5(OH)(2)Br-3 and Li-2(OH)Br
We carried out a structure refinement of a crystal which was composed
   of two phases. Phase I was up to now unknown and corresponds to
   Li-5(OH)(2)Br-3 with lattice parameters a = 4.02335(1), c = 21.5638(1)
   Angstrom, space group Mm2. Phase H is Li-2(OH)Br with lattice
   parameters a = 4.04594(3) Angstrom and space group Pm3m. The two phases
   have the a, b-plane in common and consequently part of the reflections
   overlap systematically. We performed a joint structure refinement of
   the two phases taking into account all reflections. The structure of
   Li-5(OH)(2)Br-3 is characterized by anti-perovskite like double layers
   of composition 2 x Li-2(OH)Br, which alternate with rock-salt like
   layers of composition LiBr. Results for Li-2(OH)Br are in good
   agreement with literature and confirm the correctness of the underlying
   model and the usefulness of the method employed in structure
   refinement.We carried out a structure refinement of a crystal which was
   composed of two phases. Phase I was up to now unknown and corresponds
   to Li-5(OH)(2)Br-3 with lattice parameters a = 4.02335(1), c =
   21.5638(1) Angstrom, space group I (4) over bar m2. Phase II is
   Li-2(OH)Br with lattice parameters a = 4.04594(3) Angstrom and space
   group Pm (3) over barm. The two phases have the a, b-plane in common
   and consequently part of the reflections overlap systematically. We
   performed a joint structure refinement of the two phases taking into
   account all reflections.
   The structure of Li-5(OH)(2)Br-3 is characterized by anti-perovskite
   like double layers of composition 2 x Li-2(OH)Br, which alternate with
   rock-salt like layers of composition LiBr. Results for Li-2(OH)Br are
   in good agreement with literature and confirm the correctness of the
   underlying model and the usefulness of the method employed in structure


Bauer, EM   Bellitto, C   Ibrahim, SA   Mahmoud, MR   Righini, G
Ni(II)octadecylphosphonate: an inorganic/organic layered
POLYHEDRON 22, 2003, 2463-2469.
Ni[CH3(CH2)(17)PO3] . H2O was prepared and characterized by several
   techniques and the magnetic properties were measured by using a SQUID
   magnetometer. Preliminary refinement of the X-ray diffraction powder
   data by structure-less Le Bail fitting could be obtained and the
   compound was found to crystallise in the orthorhombic space group
   Pmn2(1) with a = 5.478(7) Angstrom, b = 42.31(4) Angstrom, c = 4.725(3)
   Angstrom. Ni(II)octadecyl phosphonate is lamellar and the structure
   consists of alternating inorganic and organic layers. The inorganic
   layers are interspersed by by-layers of the octadecyl substituent and
   van der Waals contacts are established between them. IR spectroscopy
   revealed all-trans configuration of the hydrocarbonic chain. A tilt
   angle of 48.2degrees between the chain axis and the (ac) plane could be
   estimated. The temperature dependence of the molar susceptibility
   plotted as 1/chi vs. T is linear above 100 K and it follows the
   Curie-Weiss law. The Curie, C, constant suggests the presence of Ni(II)
   ion in the S = I spin state and the negative Weiss, theta, constant is
   indicative of antiferromagnetic nearest neighbour exchange
   interactions. Zero-field and field-cooled chi vs. T plots were then
   recorded. The plots show no overlap below 20 K, thus indicating that
   the compound is in an ordered magnetic state. The critical temperature
   has been located at the onset of the X vs. T plot and was found to be
   T-N = 21 K. The magnetization vs. field plots, measured at different
   temperatures, provide the indication that the compound is a
   weak-ferromagnet below TN.


Howard, CJ   Zhang, ZM
Structures and phase transition in the layered perovskite
   La0.6Sr0.1TiO3: a new orthorhombic structure solved from
   high-resolution diffraction in combination with group theoretical
The crystal structure of the layered perovskite La0.6Sr0.1TiO3 at room
   temperature has been solved by synchrotron x-ray powder diffraction in
   combination with group theoretical analysis. The structure is
   orthorhombic in Cmmm, on a cell with a = 7.7556(l), b = 7.7349(l) and c
   = 7.7910(l) Angstrom. It is believed that this is also the structure
   adopted by La2/3TiO3. Pertinent features are the alternation of fully
   and partly occupied layers of La (Sr) cations, and out-of-phase tilting
   of the TiO6 octahedra around an axis perpendicular to the direction of
   the cation ordering. The compound undergoes a second order transition
   to a tetragonal structure, the transition temperature being estimated
   as 360degreesC.


Ciurchea, D
Structure and superconducting properties of (Bi,Pb): 2223
   superconductor with 3D excess conductivity
The full pattern decomposition method by Le Bail was applied to a
   single phase orthorhombic (Bi,Pb):2223 superconductor with an
   accentuated three dimensional excess conductivity The space group Pmam,
   with the lattice parameters a = 5.2598, b = 5.5381, c = 37.174 Angstrom
   was found. The Fourier maps derived show that delocalization of the Sr
   atoms induces terracing of the Cu/Ca/Cu superconducting stacking of 0.3
   Angstrom, close to the c-axis coherence length, yielding the three
   dimensional character of the conduction evidenced by the resistivity


Coste, S   Gautier, E   Evain, M   Bujoli-Doeuff, M   Brec, R
   Jobic, S   Kanatzidis, MG
NaV1-xP2S6 (x=0.16): A new compound with infinite straight
   (1/infinity)[V0.837P2S6](-) chains that exfoliate forming gels
CHEMISTRY OF MATERIALS 15, 2003, 2323-2327.
The new 1D chalcogenophosphate material NaV0.837(6)P2S6 has been
   synthesized and its structure determined by X-ray powder diffraction
   analysis. This compound crystallizes in the monoclinic space group
   P2(1)/n with a = 6.9677(3) Angstrom, b = 5.9059(2) Angstrom, c =
   21.4537(s) Angstrom, and beta = 92.962(2)degrees [Z = 4, V = 881.66(8)
   Angstrom(3)]. The Rietveld refinement led to R-p/R-wp = 0.0208/0.0271
   (for 94 parameters refined). The material is isostructural with
   1D-NaCrP2S6 and contains infinite (1/infinity)[V0.837(6)P2S6](_) chains
   consisting of randomly occupied edge-sharing [VS6] octahedra defining
   zigzag (1/infinity)[VS4] ribbons that are capped by tetradendate [P2S6]
   ethane-like groups linked to three successive [VS6] polyhedra. Because
   of the nonstoichiometry of the phase, the charge balance can be written
   as Na+(V4+)(0.486)(V3+)(0.351)(P4+)(2)(S2-)(6). NaV0.837(6)P2S6 is
   soluble in strongly polar organic solvents such as N-methylformamide
   (NMF). The exfoliation of NaV0.837(6)P2S6 in NMF leads to gels or to
   colored colloidal solutions with complex fluid behavior that depends
   strongly on concentration.


Dinnebier, RE   Vensky, S   Panthofer, M   Jansen, M
Crystal and molecular structures of alkali oxalates: First proof of a
   staggered oxalate anion in the solid state
INORGANIC CHEMISTRY 42, 2003, 1499-1507.
The molecular and crystal structures of solvent-free potassium,
   rubidium, and cesium oxalates have been determined ab initio from
   high-resolution synchrotron and X-ray laboratory powder patterns. In
   the case of potassium oxalate K2C2O4 (a = 10.91176(7) Angstrom, b =
   6.11592(4) Angstrom, c 3.44003(2) Angstrom, orthorhombic, Pbam, Z = 2),
   the oxalate anion is planar, whereas in cesium oxalate Cs2C2O4 (a =
   6.62146(5) Angstrom, b = 11.00379(9) Angstrom, c = 8.61253(7) Angstrom,
   beta = 97.1388(4)degrees, monoclinic, P2(1)/c, Z = 4) it exhibits a
   staggered conformation. For rubidium oxalate at room temperature, two
   polymorphs exist, one (beta-Rb2C2O4) isotypic to potassium oxalate (a =
   11.28797(7) Angstrom, b = 6.29475(4) Angstrom, c = 3.62210(2) Angstrom,
   orthorhombic, Pbam, Z 2) and the other (alpha-Rb2C2O4) isotypic to
   cesium oxalate (a = 6.3276(1) Angstrom, b = 10.4548(2) Angstrom, c =
   8.2174(2) Angstrom, beta = 98.016(1)degrees, monoclinic, P2(1)/c, Z =
   4). The potassium oxalate structure can be deduced from the AlB2 type,
   and the cesium oxalate structure from the Hg99As type, respectively.
   The relation between the two types of crystal structures and the reason
   for the different conformations of the oxalate anion are discussed.

Wunschel, M   Dinnebier, RE   Carlson, S   Bernatowicz, P   van Smaalen, S
Influence of the molecular structures on the high-pressure and
   low-temperature phase transitions of plastic crystals
The crystal structures of tert-butyl-tris(trimethylsilyl)silane,
   Si[C(CH3)(3)](1) [Si(CH3)(3)](3) (Bu1), and
   di-tert-butyl-bis(trimethylsilyl)silane, Si[C(CH3)(3)](2)
   [Si(CH3)(3)](2) (Bu2), at room temperature and at 105 K have been
   determined by X-ray powder diffraction; the high-pressure behavior for
   pressures between 0 and 5 GPa is reported. The room-temperature
   structures have cubic Fm (3) over barm symmetry (Z = 4) with a =
   13.2645 (2) Angstrom, V = 2333.87 (4) Angstrom(3) for Bu1 and a =
   12.9673 (1) Angstrom, V = 2180.46 (3) Angstrom(3) for Bu2. The
   molecules are arranged in a cubic close packing (c.c.p.) and exhibit at
   least 48-fold orientational disorder. Upon cooling both compounds
   undergo a first-order phase transition at temperatures T c = 230 (5) K
   (Bu1) and Tc = 250 (5) K (Bu2) into monoclinic structures with space
   group P2(1)/n. The structures at 105 K have a = 17.317 (1), b = 15.598
   (1), c = 16.385 (1) Angstrom, gamma = 109.477 (4)degrees, V = 4172.7
   (8) Angstrom(3) and Z = 8 for Bu1 and a = 17.0089 (9), b = 15.3159 (8),
   c = 15.9325 (8) Angstrom, gamma = 110.343 (3)degrees, V = 3891.7 (5)
   Angstrom(3) and Z = 8 for Bu2. The severe disorder of the
   room-temperature phase is significantly decreased and only a two- or
   threefold rotational disorder of the molecules remains at 105 K.
   First-order phase transitions have been observed at pressures of
   0.13-0.28 GPa for Bu1 and 0.20-0.24 GPa for Bu2. The high-pressure
   structures are isostructural to the low-temperature structures. The
   pressure dependencies of the unit-cell volumes were fitted with Vinet
   equations of state and the bulk moduli were obtained. At still higher
   pressures further anomalies in the pressure dependencies of the lattice
   parameters were observed. These anomalies are explained as additional
   disorder-order phase transitions.


Asthalter, T   Franz, H   van Burck, U   Messel, K   Schreier, E   Dinnebier, R
Structure and dynamics of octamethyl-ethinyl-ferrocene: an
   organometallic rotator phase
The onset of dynamics and the structural changes of
   octamethyl-ethinyl-ferrocene around a solid-solid phase transition at
   248 K have been investigated using the novel technique of quasielastic
   nuclear forward scattering (QNFS) in a temperature range between 61 and
   257 K at a photon energy of 14.413 keV, as well as X-ray powder
   diffraction at various energies. A pronounced hysteresis for both the
   dynamical and the structural properties is observed and confirmed by
   differential-scanning calorimetry. We assign the observed phenomena to
   a first-order transition from a low-symmetry low-temperature phase to a
   high-symmetry high-temperature plastically crystalline phase with
   nearly cubic symmetry. Possible mechanisms for this transition are
   discussed in the light of our results.


Harvey, HG   Hu, J   Attfield, MP
Synthesis, structural characterization, and readsorption behavior of a
   solid solution aluminum phosphite/ethylenediphosphonate series
CHEMISTRY OF MATERIALS 15, 2003, 179-188.
Members of the new solid solution aluminum phosphite/
   ethylenediphosphonate series,
   Al-2[(O3PC2H4PO3)(1-x)(HPO3)(2x)](H2O)(2)F-2 . H2O (0 less than or
   equal to x less than or equal to 0.32), have been prepared and fully
   characterized. The full dehydration behavior of the parent material of
   this series, Al-2[O-3-PC2H4PO3](H2O)(2)F-2.H2O (x = 0) has been
   resolved. On heating the material to 230 degreesC the extraframework
   water is the primary species desorbed and the framework structure
   remains intact as determined from the crystal structure of the
   partially dehydrated material, Al-2[O3PC2H4Po3](H2O)(2)F-2.0.51(3)H2O.
   Above 150 degreesC, but more noticeably above 200 C, framework water is
   lost, resulting in the formation of 4- and 5-coordinated Al centers. By
   340 degreesC all the framework water and some fluorine is lost
   resulting in the collapse of the crystalline material. The phosphite
   substituted materials (0 less than or equal to x less than or equal to
   0.32) are shown, by diffraction and spectroscopic techniques, to be
   single-phase solid solutions. Rietveld refinement of the structure of
   the x = 0.19 member reveals that a random substitution of phosphite
   groups for diphosphonate species exists throughout the bulk of the
   material and that the remainder of the framework remains unaltered by
   incorporation of this moiety. The readsorption behavior of the
   materials (0 less than or equal to x less than or equal to 0.32)
   indicates that the temperature at which the extraframework water is
   first removed decreases as x increases and that the amount of water
   lost and degree of readsorption increase as x increases. These results
   indicate that the porosity of the materials can be controlled in a
   manner conducive to their rational design.

2003-89   ???

Allen, S   Warmingham, NR   Gover, RKB   Evans, JSO
Synthesis, structure and thermal contraction of a new low-temperature
  polymorph of ZrMo(2)(O)8
CHEMISTRY OF MATERIALS 15, 2003, 3406-3410.

Meejoo, S   Kariuki, BM   Kitchin, SJ   Cheung, EY   Albesa-Jove, D   Harris, KDM
Structural aspects of the beta-polymorph of (E)-4-formylcinnamic acid:
   Structure determination directly from powder diffraction data and
   elucidation of structural disorder from solid-state NMR
HELVETICA CHIMICA ACTA 86, 2003, 1467-1477.
Among the derivatives of (E)-cinnamic acid for which the solid-state
   photochemical properties have been studied, (E)-4-formylcinnamic acid
   (1) has already received much attention. Given the inability to prepare
   single crystals of the beta-polymorph of 1 that are of suitable size
   and quality for structural characterization by single-crystal X-ray
   diffraction, the structure of this material was determined directly
   from powder X-ray-diffraction data by means of the genetic-algorithm
   technique for structure solution, followed by Rieveld refinement.
   High-resolution solid-state C-13-NMR was also applied to elucidate
   details of structural disorder concerning the orientation of the formyl
   group, and provided independent support for the disorder model
   established form the Rietveld refinement. The reported structure
   establishes that the beta-phase of 1 is not structurally anomalous
   among photoreactive (E)-cinnamic acid crystals, and finally resolves a
   long-standing controversy concerning the structural properties of this

Mora, AJ   Fitch, AN   Ramirez, BM   Delgado, GE   Brunelli, M   Wright, J
Structure of lithium benzilate hemihydrate solved by simulated
   annealing and difference Fourier synthesis from powder data
The crystal structure of lithium benzilate hemihydrate
   (C14H11O3-Li+.0.5H(2)O) was solved from synchrotron powder diffraction
   data. This compound crystallizes in the monoclinic space group P2(1)/a.
   The structure was solved via the direct space search for two benzilate
   fragments using the simulated-annealing program DASH, localization of
   the lithium ions and water molecule from a difference Fourier map, and
   a restrained Rietveld refinement (R-wp = 0.0687). The structure is a
   coordination polymer of [Li-2(C14H11O3) (2).H2O](2) tetramers building
   helical fourfold one-dimensional channels parallel to [010]. Inside the
   channels the tetrahedral coordination spheres of the lithium ions
   contain hydroxyl and carbonyl groups, and water molecules. The water
   molecule functions as the cohesive entity forming extended
   hydrogen-bonded chains running along [010], and bifurcated donor
   hydrogen bonds with the two nearest carboxylates. At the outer edge of
   the channels, weaker intermolecular C-H...Ph hydrogen bonds along [100]
   and [001] contribute to the supramolecular aggregation of the structure.


Dinnebier, R   Muller, J
New insights into an old reaction. High-resolution X-ray powder
   diffraction of Wiberg's aminoalane intermediate
INORGANIC CHEMISTRY 42, 2003, 1204-1210.
In accordance with the procedure described by E. Wiberg, Me3Al-NH3 was
   heated as a bulk material in inert atmosphere to give a colorless
   liquid which slowly loses methane. Close to the end of this elimination
   reaction, the melt crystallized to give a microcrystalline powder of
   (Me2AlNH2)(x). The structure of this intermediate has been solved by
   the method of high-resolution X-ray powder diffraction. The compound
   crystallizes in the monoclinic space group C2/c with the cell
   parameters of a = 15.0047(6) Angstrom, b = 8.7500(2) Angstrom, c =
   24.4702(8) Angstrom, and beta = 107.290(2)degrees, with eight trimers
   (Me(2)AINH(2))(3) Per unit cell. These trimers crystallize in a boat
   conformation in contrast to the known trimers of the same composition
   where a twist-boat conformation had been found by single crystal
   determination. Different conformers of (Me2AINH2)3 have been
   investigated by theoretical methods (HF/6-31G(d), B3LYP/6-31 G(d),
   B3LYP/6-311G(d,p), MP2(fc)/6-31 G(d), and MP2(fc)/6-311G(d,p)). The
   twist-boat and the chair conformer correspond to minima at the
   potential energy surface, whereas the boat conformer corresponds to a
   first-order transition state (relative energies of 0.45-2.56 kJ/mol
   (boat) and 6.66-11.91 kJ/mol (chair)). Relaxed scans of the potential
   energy surface at the HF/6-31G(d) and B3LYP/6-31G(d) levels have shown
   that the boat conformer (C-s symmetry) connects two enantiomers of the
   twist-boat form (C-2 symmetry).


Jorgensen, JD   Avdeev, M   Hinks, DG   Burley, JC   Short, S
Crystal structure of the sodium cobaltate deuterate superconductor
   NaxCoO2  .  4xD(2)O (x approximate to 1/3)
PHYSICAL REVIEW B 68, iss 21, 2003, 214517
Neutron and x-ray powder diffraction have been used to investigate the
   crystal structures of a sample of the newly-discovered superconducting
   sodium cobaltate deuterate compound with composition
   Na0.31(3)CoO2.1.25(2)D2O and its anhydrous parent compound
   Na0.61(1)CoO2. The anhydrous parent compound Na0.61(1)CoO2 has two
   partially occupied Na sites sandwiched, in the same plane, between CoO2
   layers. When Na is removed to make the superconducting composition, the
   Na site that experiences the strongest Na-Co repulsion is emptied while
   the occupancy of the other Na site is reduced to about one third. The
   deuterate superconducting compound is formed by coordinating four D2O
   molecules (two above and two below) to each remaining Na ion in a way
   that gives Na-O distances nearly equal to those in the parent compound.
   One deuteron of the D2O molecule is hydrogen bonded to an oxygen atom
   in the CoO2 plane and the oxygen atom and the second deuteron of each
   D2O molecule lie approximately in a plane between the Na layer and the
   CoO2 layers. This coordination of Na by four D2O molecules leads in a
   straightforward way to ordering of the Na ions and D2O molecules
   consistent with the observation of additional shorter-range scattering
   features in the diffraction data. The sample studied here, which has
   T-c=4.5 K, has a refined composition of Na0.31(3)CoO2.1.25(2)D2O, in
   agreement with the expected 1:4 ratio of Na to D2O. These results show
   that the optimal superconducting composition should be viewed as a
   specific hydrated compound, not a solid solution of Na and D2O (H2O) in
   NaxCoO2.D2O. The hydrated superconducting compound may be stable over a
   limited range of Na and D2O concentration, but studies of T-c and other
   physical properties vs Na or D2O composition should be viewed with
   caution until it is verified that the compound remains in the same
   phase over the composition range of the study.


Jurgens, B   Irran, E   Senker, J   Kroll, P   Muller, H   Schnick, W
Melem (2,5,8-triamino-tri-s-triazine), an important intermediate during
   condensation of melamine rings to graphitic carbon nitride: Synthesis,
   structure determination by X-ray powder diffractometry, solid-state
   NMR, and theoretical studies
Single-phase melem (2,5,8-triamino-tri-s-triazine) C6N7(NH2)(3) was
   obtained as a crystalline powder by thermal treatment of different less
   condensed C-N-H compounds (e.g., melamine C3N3(NH2)(3), dicyandiamide
   H4C2N4, ammonium dicyanamide NH4[N(CN)(2)], or cyanamide H2CN2,
   respectively) at temperatures up to 450 degreesC in sealed glass
   ampules. The crystal structure was determined ab initio by X-ray powder
   diffractometry (Cu Kalpha(1): P2(1)/c (No. 14), a = 739.92(1) pm, b =
   865.28(3) pm, c = 1338.16(4) pm, beta = 99.912(2)degrees, and Z = 4).
   In the solid, melem consists of nearly planar C6N7(NH2)(3) molecules
   which are arranged into parallel layers with an interplanar distance of
   327 pm. Detailed C-13 and N-15 MAS NMR investigations were performed.
   The presence of the triamino form instead of other possible tautomers
   was confirmed by a CPPI (cross-polarization combined with polarization
   inversion) experiment. Furthermore, the compound was characterized
   using mass spectrometry, vibrational (IR, Raman), and photoluminescence
   spectroscopy. The structural and vibrational properties of molecular
   melem were theoretically studied on both the B3LYP and the MP2 level. A
   structural optimization in the extended state was performed employing
   density functional methods utilizing LDA and GGA. A good agreement was
   found between the observed and calculated structural parameters and
   also for the vibrational frequencies of melem. According to
   temperature-dependent X-ray powder diffractometry investigations above
   560 degreesC, melem transforms into a graphite-like C-N material.


Hauback, BC   Brinks, HW   Jensen, CM   Murphy, K   Maeland, AJ
Neutron diffraction structure determination of NaAlD4
The structure of NaAlD4 has been determined from Rietveld-type
   refinements of powder neutron diffraction data at 8 and 295 K. The
   space group is I4(1) la with a = 501.19(l) and c = 1131.47(5) pm at 295
   K. The Na atoms are surrounded by eight D atoms from eight different
   [AlD4](-) tetrahedra in the geometry of a distorted square antiprism.
   The two different Na-D distances are nearly equal: 240.3(2) and
   240.5(2) pm at 8 K and 243.1(2) and 243.9(2) pm at 295 K. The Al-D
   distance is 162.7(2) and 162.6(2) pm at 8 and 295 K, respectively.


Cheung, EY   Kitchin, SJ   Harris, KDM   Imai, Y   Tajima, N   Kuroda, R
Direct structure determination of a multicomponent molecular crystal
   prepared by a solid-state grinding procedure


Schwarz, U   Akselrud, L   Rosner, H   Ormeci, A   Grin, Y   Hanfland, M
Structure and stability of the modulated phase Sb-II
PHYSICAL REVIEW B 67, 2003, iss 21, 214101.
The crystal structure of Sb-II has been determined using
   angle-dispersive x-ray diffraction of synchrotron radiation. The
   crystal structure comprises an interpenetrating assembly of a
   tetragonal host sublattice with symmetry I422 and a tetragonal guest
   sublattice of symmetry I422, which realize common a axes but different
   c axes. Weak extra peaks that are also reported in recent
   investigations performed independently are attributed to modulation
   waves of the atomic positions in both sublattices. A refinement using
   full profiles of powder-diffraction data was performed in the
   four-dimensional superspace group L--111(I422):L--111(I422). The
   structural investigation is accompanied by ab initio full-potential
   band-structure calculations confirming the experimentally determined
   modification sequence. Fitting equations of state to the results of
   these computations generates pressure-volume relations which are in
   excellent agreement with the experimental data. On the basis of
   total-energy calculations, an earlier proposed crystal structure of the
   tetragonal phase has to be reconsidered in the light of the composite
   arrangement in Sb-II.

Hummer, K   Puschnig, P   Ambrosch-Draxl, C
Ab initio study of anthracene under high pressure
PHYSICAL REVIEW B 67, 2003, iss 18, 184105.
The pressure effect on the internal molecular orientation, the
   electronic and optical properties of crystalline anthracene is
   calculated up to 10.2 GPa by performing density-functional
   calculations. As the only input for our ab initio calculations we use
   the lattice parameters experimentally determined by x-ray powder
   diffraction under pressure and optimize the internal geometry with
   respect to the three angles theta, chi, and delta, which define the
   orientation of the molecules inside the unit cell. For the optimized
   structures the isothermal bulk moduli, the electronic band structures,
   and dielectric tensors as a function of the unit-cell volume are
   calculated. The structure optimizations using the local-density
   approximation and the generalized gradient approximation
   exchange-correlation potentials give very similar results and agree
   well with the internal geometry determined from experiment. This gives
   rise to the conclusion that the application of such approximations for
   the description of organic molecular crystals within density-functional
   theory is valid. Moreover, the electron distribution clearly shows a
   finite density between the molecules in the unit cell, which increases
   with pressure due to the enhancement of the intermolecular
   interactions. These findings support the interpretation that the
   bonding mechanism in anthracene is not solely van der Waals interaction.


Lotsch, BV   Senker, J   Kockelmann, W   Schnick, W
Investigation of structural and dynamic properties of NH4[N(CN)(2)] by
   means of X-ray and neutron powder diffraction as well as vibrational
   and solid-state NMR spectroscopy
The crystal structure, spectroscopic and thermal properties of ammonium
   dicyanamide NH4[N(CN)(2)] have been thoroughly investigated by means of
   temperature-dependent single-crystal X-ray and neutron powder
   diffraction, vibrational and MAS-NMR spectroscopy as well as
   thermoanalytical measurements. The comprehensive elucidation of
   structural details is of special interest with respect to the unique
   solid-state transformation of ammonium dicyanamide into dicyandiamide.
   This reaction occurs at temperatures >80degreesC and it represents the
   isolobal analogue of Wohler's historic transformation of ammonium
   cyanate into urea. NH4[N(CN)(2)] crystallizes in the monoclinic space
   group P2(1)/c with lattice constants a = 3.7913(8)1 b = 12.412(2), c =
   9.113(2) Angstrom, beta = 91.49(2)degrees and Z = 4 (single-crystal
   X-ray data, T = 200 K). The temperature dependence of the lattice
   constants shows anisotropic behavior, however, no evidence for phase
   transitions in the investigated temperature range was observed. The
   hydrogen positions could be localized by neutron diffraction (10-370
   K), and the temperature-dependent behavior of the ammonium group has
   been analyzed by Rietveld refinements using anisotropic thermal
   displacement parameters. They were interpreted by utilizing a rigid
   body model and extracting the libration and translation matrices of the
   ammonium ion by applying the TLS formalism. The results obtained by the
   diffraction methods were confirmed and supplemented by vibrational
   spectroscopy and solid-state 1 5 N and C-13 MAS-NMR investigations.


Pospisil, M   Capkova, P   Weissmannova, H   Klika, Z
   Trchova, M   Chmielova, M   Weiss, Z
Structure analysis of montmorillonite intercalated with rhodamine B:
   modeling and experiment
The intercalation process and the structure of montmorillonite
   intercalated with [rhodamine B](+) cations have been investigated using
   molecular modeling (molecular mechanics and molecular dynamics
   simulations), X-ray powder diffraction and IR spectroscopy. The
   structure of the intercalate depends strongly on the concentration of
   rhodamine B in the intercalation solution. The presence of two phases
   in the intercalated structure was revealed by modeling and X-ray powder
   diffraction: (i) phase with basal spacing 18 Angstrom and with bilayer
   arrangement of guests and (ii) phase with average basal spacing 23
   Angstrom and with monolayer arrangement of guests. In both phases the
   monomeric and dimeric arrangement can coexist in the interlayer space.
   Three types of dimers in the interlayer structure have been found by
   modeling: (i) H-dimer (head-to-head arrangement) present in the 18
   Angstrom phase, (ii) sandwich type of the head-to-tail arrangement
   (present in the 23 Angstrom phase) and (iii) J-dimer (head-to-tail
   arrangement) present in the 23 Angstrom phase.


Mairesse, G   Roussel, P   Vannier, RN   Anne, M   Nowogrocki, G
Crystal structure determination of alpha-, beta- and gamma-Bi4V2O11
   polymorphs. Part II: crystal structure of alpha-Bi4V2O11
SOLID STATE SCIENCES 5, 2003, 861-869.
The crystal structure of alpha-Bi4V2O11 was solved in the A2 space
   group and refined using combined X-ray single crystal and neutron
   powder diffraction data in the following unit cell a = 16.5949(3)
   Angstrom (3 x a(m) = 5.5316 Angstrom), b = 5.6106(1) Angstrom, c =
   15.2707(3) Angstrom, gamma = 90.260(2)degrees. It is built upon
   [Bi2O2](2+) layers spaced with vanadium-oxygen slabs where the vanadium
   atoms exhibit three different oxygen environments. The main
   characteristic of these V-O slabs is a well defined dimeric unit with
   two trigonal bipyramids sharing one edge and connected to two VO
   tetrahedra. These rigid blocks extend along [100] and are spaced with a
   disordered area where different V-O trigonal bipyramids are
   interconnected. A possible scheme to explain the actual 6a(m)
   superlattice is proposed. It also accounts for the diffusion lines
   systematically observed along [100] by SAED. A relationship between the
   crystal structures of the three Bi4V2O11 polymorphs and their
   corresponding conductivity is tentatively suggested.


Ouyang, X   Tsai, TY   Chen, DH   Huang, QJ   Cheng, WH   Clearfield, A
Ab initio structure study from in-house powder diffraction of a novel
   ZnS(EN)(0.5) structure with layered wurtzite ZnS fragment
CHEMICAL COMMUNICATIONS iss 7, 2003, 886-887.
The solvothermal reaction of elemental zinc with sulfur in
   ethylenediamine ( en) as solvent yields [ZnS.0.5(NH2CH2CH2NH2)], 1, an
   unprecedented ethylenediamine pillared ZnS layered compound, containing
   two dimensional (2-D) boat-type 6-membered rings, which was
   characterized by ab initio structure solution from powder diffraction
   data (SDPD).


Birkett, HE   Cherryman, JC   Chippendale, AM   Evans, JSO
   Harris, RK   James, M   King, IJ   McPherson, GJ
Structural investigations of three triazines: solution-state NMR
   studies of internal rotation and structural information from
   solid-state NMR, plus a full structure determination from powder x-ray
   diffraction in one case
Three model 2,4,6-tris(amino)-1,3, 5-triazines, structurally related to
   a dyestuff molecule previously studied by NMR, were synthesized in
   order to enable the effects of rotamer exchange on the NMR spectra to
   be investigated in more detail. Two of the compounds are novel.
   Internal rotation of the triazine ring substituents was studied by
   variable-temperature solution-state H-1, C-13 and N-15 NMR
   spectroscopy. All the expected rotamers were detected for each
   molecule. Rotamer exchange rates varied from slow to fast over the
   temperature range -40 to 90degreesC, as observed for the dyestuff
   molecule itself. Solid-state C-13 and N-15 NMR provided information
   about the structures of the solid molecules. A full crystal structure
   determination from high-resolution powder x-ray diffraction was
   achieved for one of the molecules using simulated annealing techniques.
   Ab initio MO and N-15 NMR chemical shift calculations, based on
   energy-minimized structures derived from the x-ray structure
   determination, enabled the effect of intermolecular hydrogen bonding on
   the N-15 NMR chemical shifts to be studied. The results compared
   favourably with the experimental solid-state N-15 NMR shifts.


Rocquefelte, X   Boucher, F   Gressier, P   Ouvrard, G
First-principle study of the intercalation process in the LixV2O5 system
CHEMISTRY OF MATERIALS 15, 2003, 1812-1819.
A theoretical study of the lithium intercalated LixV2O5 System has been
   performed using a dual approach, based on A initio calculations and
   experimental data. Two main aspects have been investigated: the atomic
   structure of each phase and the voltage of a lithium battery with a
   positive electrode made of LixV2O5. This approach leads to proposal of
   the full atomic arrangement for the different phases obtained during
   the reaction. Particularly, a structural arrangement is proposed for
   the debated omega-Li3V2O5 phase, based on a full simulation of its
   X-ray powder diagram. For the first time, an antiferromagnetic ordering
   is envisioned for xi-Li2V2O5. Finally, a very good simulation of the
   experimental open circuit voltage (OCV) curve of the battery, from x =
   0 to x = 3, is obtained when the magnetic interactions are considered.


Vors, JP   Gerbaud, V   Gabas, N   Canselier, JP   Jagerovic, N
   Jimeno, ML   Elguero, J
The structure of the agrochemical fungicidal
   4-chloro-3-(3,5-dichlorophenyl)-1H-pyrazole (RPA 406194) and related
TETRAHEDRON 59, 2003, 555-560.
The difficulties to obtain convenient monocrystals of the important
   fungicide RPA 406194 have been overcome by a combination of solid state
   C-13 NMR, X-ray powder diffraction and molecular modeling. The
   compound, a 3-aryl tautomer, crystallizes forming infinite chains of
   molecules bonded by N-H...N hydrogen bonds, leading to needle-shaped
   crystals. The tautomerism (equilibrium constant and energy barrier) of
   this compound in solution has been studied.


Mairesse, G   Roussel, P   Vannier, RN   Anne, M   Pirovano, C   Nowogrocki, G
Crystal structure determination of alpha, beta and gamma-Bi4V2O11
   polymorphs. Part I: gamma and beta-Bi4V2O11
SOLID STATE SCIENCES 5, 2003, 851-859.
Using combined X-ray single crystal and neutron powder
   thermodiffraction data, the crystal structure of the high temperature
   gamma-form of Bi4V2O11 was confirmed and accurately refined in the
   I4/mmm space group and that of the beta-form was entirely determined in
   the centrosymmetric Amam space group. The two-fold superlattice
   characterising the beta structure is the result of an ordering process
   involving corner-sharing V-O tetrahedra and disordered trigonal
   bipyramids. A possible scheme for the gamma <----> beta phase
   transition is proposed.


Wallwork, KS   Pring, A   Taylor, MR   Hunter, BA
A model for the structure of the hydrated aluminum phosphate, kingite
   determined by ab initio powder diffraction methods
AMERICAN MINERALOGIST 88, 2003, 235-239.
The crystal structure of kingite, Al-3(PO4)(2)(F,OH)(2).8(H2O,OH), a
   secondary mineral from a Cambrian-Precambrian phosphate deposit at
   Tom's Quarry, near Kapunda, South Australia, has been determined from a
   powder sample using synchrotron X-ray diffraction data. The structure
   was determined ab initio by direct methods and refined to R-Bragg =
   0.022 and R-wp = 0.039 using the Rietveld method. The triclinic
   structure was solved and refined in the space group P (1) over bar1, a
   = 9.377(1), b = 10.113(1), c = 7.138(1) Angstrom, alpha = 97.60(1),
   beta = 100.88(1), gamma = 96.01(1)degrees, V = 653.0(1) Angstrom(3), Z
   = 2. The structure of kingite contains finite strings of three corner
   sharing Alphi(6) octahedra (where phi represents O, OH-, F-, or H2O).
   These strings are cross-linked via PO4 tetrahedra to produce layers
   that are perpendicular to [100]. The layers are linked via hydrogen
   bonding through H2O located in the interlayer space. Kingite is shown
   to have a different stoichiometry to that reported earlier. The
   relationship of kingite to the structures of wavellite,
   Al-3(PO4)(2)(OH)(3).5H(2)O, and mitryaevaite,
   Al-5(PO4)(2)[(P,S)O-3(OH,O)](2)F-2(OH)(2)(H2O)(8).6.48H(2)O, are
   briefly discussed.


Serre, C   Ferey, G
Synthesis and structure determination from powder data of the first
   organically templated tin(IV) phosphate: MIL-76 or
CHEMICAL COMMUNICATIONS iss 15, 2003, 1818-1819.
The first organically templated tin(IV) phosphate has been isolated and
   its structure solved from powder X-ray diffraction data; it exhibits a
   one-dimensional inorganic network built up from chains of trimers of
   tin( IV) octahedra on which phosphate tetrahedral groups are grafted
   interacting with water molecules and organic moieties.


Mulagaleev, RF   Soloviev, LA   Blokhin, AI   Kirik, SD
Synthesis and structure of
   [Pd(NH3)(4)][cis-Pd(NH3)(2)(SO3)(2)][Pd(NH3)(3)(SO3)]  .  H2O
new palladium compound 29, 2003, 256-260.
   [Pd(NH3)(4)][cis-Pd(NH3)(2)(SO3)(2)][Pd(NH3)(3)(SO3)] . H2O (I) was
   synthesized and its structure was studied by X-ray powder diffraction
   method. In the course of the synthesis, the initial
   trans-diamminesulfite anionic complex is transformed into the
   cis-configuration. Further heating in aqueous solution results in
   isomerization of a substance into a neutral complex [Pd(NH3)(3)(SO3)].
   Crystals I are triclinic: a = 10.3297(2) Angstrom, b = 14.1062(3)
   Angstrom, c = 6.853 1(1) Angstrom, alpha = 101.36(0)degrees, beta =
   92.74(0)degrees, gamma = 92.71(0)degrees, space group P (1) over bar.
   Structure I consists of the columns with alternating
   cis-[pd(NH3)(2)(SO3)(2)](2-) and [Pd(NH3)(3)(SO3)] complexes and
   [Pd(NH3)(4)](2+) ions between the columns.


Ouyang, X   Tsai, TY   Chen, DH   Huang, QJ   Cheng, WH   Clearfield, A
Ab initio structure study from in-house powder diffraction of a novel
   ZnS(EN)(0.5) structure with layered wurtzite ZnS fragment (pg 886, 2003)
CHEMICAL COMMUNICATIONS iss 9, 2003, 1107-1107


Laco, JII
Structural studies of poly[(2S,3S)-2,3-dimethoxybutylene alkanamide]s
POLYMER 44, 2003, 1935-1940.
The structural characterization of a series of stereoregular polyamides
   4,n (n = 8, 10, 12), which were obtained from polycondensation of
   (2S,3S)-2,3-dimethoxy-1,4-butanediamine with aliphatic dicarboxylic
   acids, has been carried out. X-ray diffraction of powder and fiber
   samples were analyzed together with electron diffraction patterns of
   single crystals obtained by isothermal crystallization in solution.
   Experimental results based on lattice parameters data were used to
   build a preliminary crystal model using the Cerius program. The main
   characteristic of the proposed model is the presence of intermolecular
   hydrogen bonds along the crystal a direction, similarly arranged to
   conventional nylons.


Celotti, G   Landi, E
A misunderstood member of the nagelschmidtite family unveiled:
   structure of Ca5Na2(PO4)(4) from X-ray powder diffraction data
During the development of procedures to synthesize carbonate
   hydroxyapatite with properties resembling those of biological material,
   a new phase was found to form after high temperature treatments in the
   presence of sodium. The compound was isolated and analytically
   characterized, leading to its identification as Ca5Na2(PO4)(4): an
   analogous Ca-Na phosphate was previously described, but with rather
   poor diffraction data and uncertain stoichiometry. Accurate XRD powder
   patterns revealed a hexagonal cell, space group P6(3)mc (186), a =
   10.64 Angstrom, c = 21.71 Angstrom, Z = 6, rho = 2.93 g/cm(3), with the
   a axis double and the c axis triple those of the subcell typical of
   alpha-phases in the well-known system A(2)XO(4) (or ABXO(4)). The
   complete structural determination was carried out and the relevant
   aspects and properties discussed.


Grzywa, M   Rafalska-Lasocha, A   Lasocha, W
X-ray powder diffraction data of potassium
   mu-oxo-bis(oxodiperoxovanadate)(4-) hydrate K-4[O{VO(O-2)(2)}(2)]H2O
POWDER DIFFRACTION 18, 2003, 248-251.
The potassium mu-Oxo-bis(oxodiperoxovanadate)(4-) hydrate
   K-4[O{VO(O-2)(2)}(2)]*H2O was prepared, and its X-ray powder
   diffraction patterns have been recorded at room temperature. The unit
   cell parameters were refined to a=6.7097(1)Angstrom,
   b=9.9574(1)Angstrom, c=15.8250(3)Angstrom, beta=93.69(6)degrees, space
   group P2(1)/c (14). The sample of K4V2O11*H2O was characterized by IR
   spectroscopy and analytical investigation. Results of crystal structure
   refinement by Rietveld method are presented; final R-F and R-wp are 13
   and 16%, respectively.

Wunschel, M   Dinnebier, RE   Carlson, S   Van Smaalen, S
High-pressure phase transitions in tetrakis(trimethylsilyl)silane
HIGH PRESSURE RESEARCH 23, 2003, 425-437.
The compound tetrakis(trimethylsilyl)silane S-i[Si(CH3,)(3)](4) (TSi)
   has been studied at room temperature for pressures up to 2 1.5(1) GPa,
   using X-ray powder diffraction with synchrotron radiation. Three
   different phases are reported in the investigated pressure range. The
   c.c.p.-type structure is stable up to a pressure of 0.19(1) GPa (Fm (3)
   over barm, a = 13.52110)Angstrom, V = 2471.95(1)Angstrom(3), Z = 4 at
   0.02(1)GPa). It shows a severe orientational disorder of the molecules.
   At pressures 0.19(1)-0.71(1)GPa a monoclinic phase (HP1) is found with
   space group P2(1)/n and Z=8 (a = 17.746(1)Angstrom, b =
   16.098(1)Angstrom, c= 16.871(1)Angstrom, gamma = 111.437(5)degrees and
   V = 4486.3(8) Angstrom(3) at 0.24(1)GPa). Another monoclinic phase
   (HP2) exists at pressures 0.52(1)-8.67(5)GPa. This phase has a smaller
   unit cell than the HP1 phase with Z(.)=2 (a =8.3778(8)Angstrom,
   b=9.1050(7)Angstrom, c= 13.3024(8)Angstrom, gamma= 111.63(1)degrees and
   V = 943.22(6) Angstrom(3) at 1.73(2)GPa). The pressure dependencies of
   the unit-cell volumes are successfully described by Mumaghan or
   Vinet-type equations of state. The structures at different pressures
   and temperatures of TSi and related compounds are described as
   distorted superstructures of the c.c.p. arrangement. The occurrence of
   different superstructures is rationalized as the result of an optimized
   packing of ordered molecules of various shapes.


Fantin, G   Fogagnolo, M   Bortolini, O   Masciocchi, N   Galli, S   Sironi, A
Polymorphism of dehydrocholic acid: crystal structure of the beta-phase
   and guest-mediated solid phase conversion
NEW JOURNAL OF CHEMISTRY 27, 2003, 1794-1800.
Dehydrocholic acid may be obtained in two polymorphic forms: alpha and
   beta. The complete characterization and the crystal structure of the
   beta-phase (obtained by unconventional powder diffraction methods) are
   described and discussed. Conversion of the alpha-form into the
   thermodynamically more stable beta-polymorph may be obtained through a
   room temperature solvent-mediated process. On the other hand,
   transformation of the beta-form into the alpha-form is realized through
   two distinct pathways: via a temperature-mediated process or as a
   guest-mediated solid state conversion, without the intervention of an
   amorphous state. R-(+)-Methyl p-tolyl sulfoxide is the guest of choice
   for this unusual beta-to-alpha transformation.


Barea, E   Navarro, JAR   Salas, JM   Masciocchi, N   Galli, S   Sironi, A
[Cu(4-oxopyrimidinate)(2)  .  nH(2)O]infinity: a robust sodalite
   type metal-organic framework exhibiting a rich host-guest chemistry
POLYHEDRON 22, 2003, 3051-3057.
Reaction of Cu2+ salts with 4-hydroxypyrimidine (4-Hpymo) in
   water:ammonia (9:1) solutions at room temperature leads to formation of
   either [Cu(4-pymo)(2)(NH3)(2)(H2O)(2)] (1) or
   [Cu(4-pymo)(2)(.)nH(2)O](infinity) (2), depending on which crystal
   nucleation process occurs. Selective formation of 2 is possible by
   using non-coordinating Et3N as a base. X-ray diffraction analyses have
   been performed in both cases showing that 1 is a mononuclear compound
   in which the heterocyclic ligands monodentately coordinate the copper
   ions through the N1 nitrogen atom. 2 is a 3D socialite type open
   framework, in which each 4-pymo ligand bridges two copper ions through
   both nitrogen atoms in the N,N'-exobidentate mode. Heating 1 at 110
   degreesC in air generates an amorphous phase (2a), which shows the same
   chemical analysis and spectroscopic properties as dehydrated 2.
   Crystalline [Cu(4-pymo)(2.)nH(2)O](infinity) (2), possesses interesting
   physico-chemical properties related to its porous nature. Indeed, this
   material reversibly absorbs N-2 and water vapour with minimal
   structural changes.


Cerný, R. & Alami-Yadri, K.
Orthorhombic Yb5Si4 from synchrotron powder data
Acta Cryst. E59, 2003, i1-i3.

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