2006 entries 
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Fukuda, K   Hasegawa, H   Iwata, T   Hashimoto, S
Crystal structure of calcium cobalt orthophosphate, CaCo[Ca0.1Co0.9](PO4)(2)
POWDER DIFFRACTION   21, 2006,220-224
Ca1.1Co1.9(PO4)(2) ,   P2(1)/n, Z = 4
laboratory X-ray powder diffraction data (Co K alpha)
using direct methods and the Rietveld refinement.


Henry, N   Mentre, O   Abraham, F   MacLean, EJ   Roussel, P
Polycationic disorder in [Bi6O4(OH)(4)](NO3)(6): Structure
   determination using synchrotron radiation and microcrystal X-ray
bismuth basic nitrate [Bi6O4(OH)(4)(NO3)(6)
rhombohedral hexagonal unit cell , Z = 6, space group R-3.
determined at 150(2) K by synchrotron X-ray


Pan, ZG   Xu, MC   Cheung, EY   Platts, JA   Harris, KDM   Constable, EC
   Housecroft, CE
Solid-state structural properties of 2,4,6-trimethoxybenzene
   derivatives, determined directly from powder X-ray diffraction data in
   conjunction with other techniques
2,4,6-trimethoxybenzyl alcohol,
powder X-ray diffraction data,
direct-space Genetic Algorithm (GA) technique for structure solution
   followed by Rietveld refinement.


Kahlenberg, V   Kaindl, R   Tobbens, DM
The crystal structure of the interrupted framework silicate
   K9.6Ca1.2Si12O30 determined from laboratory X-ray diffraction data
potassium calcium silicate  K9.6Ca1.2Si12O30 (or K8CaSi10O25)
direct methods aided by distance least squares optimization
laboratory X-ray powder diffraction data.
R3c   Z = 3,

2006-5 ??

Zhizhin, MG   Pounds, HA   Spiridonov, FM   Komissarova, LN   Dorhout, PK
Characterization and structural determination of a new sodium lanthanum
   phosphate thiosulfate, Na2La[PO4][S2O3]
Na2La[PO4]S2O3]. Z = 4 in the space group P2(1)/c.
The crystal structure was determined using a Rietveld analysis of the powder
   diffraction data.


Lasocha, W    Rafalska-Lasocha, A
Synthesis and X-ray crystal structure investigations of the complexes
   of a proton sponge with selected inorganic acids: Crystal structure of
   DMAN.HI complex


Platteau, C   Lefebvre, J   Hemon, S   Affouard, F   Willart, JF   Derollez, P
Ab initio structure determination of two anhydrous forms of
   alpha-lactose by powder X-ray diffraction
ZEITSCHRIFT FUR KRISTALLOGRAPHIE Part 2, Suppl 23 (2006) 595-600.
stable form of alpha-lactose is triclinic P1, Z = 2,
hygroscopic anhydrous alpha-lactose, P21, Z = 2.
The starting structural models were found by a Monte-Carlo simulated
   annealing method. The final structures were obtained through Rietveld
   refinements with soft restraints on interatomic bond lengths and bond
   angles and crystalline energy minimisation to locate the H atoms of the
   hydroxyl groups.


Wolcyrz, M   Paciak, M   Kowalczyk, J   Maciejewski, M
Crystal structure of silver salicylate C7H5AgO3 solved by reverse
   Monte-Carlo method from X-ray powder diffraction data and confirmed on
   single crystal
silver salicylate C7H5AgO3
solved originally on powder sample by molecular modeling and reverse
   Monte-Carlo (RMC) algorithm and then confirmed by X-ray diffraction
   single crystal structure solution and refinement.
laboratory X-ray sources.

2006-11   ??

Tamura, R   Mizuta, M   Yabunaka, S   Fujimoto, D   Ariga, T   Okuhara, S
   Ikuma, N   Takahashi, H   Tsue, H
Induction and inhibition of preferential enrichment by controlling the
   mode of the polymorphic transition with seed crystals
   approach employing the Monte Carlo method with the Rietveld refinement
   for the structure solution from the powder X-ray diffraction data.

2006-12 ??

Zucca, A   Petretto, GL   Stoccoro, S   Cinellu, MA   Minghetti, G
   Manassero, M   Manassero, C   Male, L   Albinati, A
Dinuclear C,N,C cyclometalated platinum derivatives with bridging
   delocalized ligands. Fourfold deprotonation of 6,6 '-diphenyl-2,2
   '-bipyridine, H4L, promoted by "Pt(R)(2)" fragments (R = Me, Ph).
   Crystal structures of [Pt-2(L)(3,5-Me(2)py)(2)] and {Pt-2(L)(dppe)}(2)
   (dppe=1,2-bis(diphenylphosphino)ethane). X-ray powder diffraction of
ORGANOMETALLICS 25, 2006, 2253-2265.
a powder X-ray diffraction analysis has been performed on
complex   [Pt-2(L)(CO)(2)].


Guo, F   Cheung, EY   Harris, KDM   Pedireddi, VR
Contrasting solid-state structures of trithiocyanuric acid and cyanuric
CRYSTAL GROWTH & DESIGN 6, 2006, 846-848.
trithiocyanuric acid (TTCA)
   structure determination directly from powder X-ray
   diffraction data, using the direct-space genetic algorithm technique
   for structure solution followed by Rietveld refinement.


Mondal, S   Mukherjee, M   Chakraborty, S   Mukherjee, AK
A novel three-dimensional network containing Pr(III) ions and tartrate:
   Synthesis, spectroscopic, thermal, ab initio X-ray powder structure
   analyses, and photoluminescence properties
CRYSTAL GROWTH & DESIGN 6, 2006, 940-945.
praseodymium tartrate [Pr(C4H4O6)(C4H5O6)(H2O)]
P2(1)2(1)2(1), and Z = 4.
The crystal structure has been solved from
   laboratory X-ray powder diffraction data using a direct space global
   optimization technique and refined by the Rietveld method.


Guo, F   Casadesus, M   Cheung, EY   Coogan, MP   Harris, KDM
On the spontaneous induction of chirality in the preparation of
   Werner's complex cis-[CoBr(NH3)(en)(2)]Br-2
CHEMICAL COMMUNICATIONS issue 17, 2006, 1854-1856.
structure determination from powder X-ray diffraction data,


Albov, DV   Jassem, A   Kuznetsov, AI
An independent refinement of H-atom coordinates from laboratory X-ray
   powder data in tetraformaltrisazine
tetraformaltrisazine (systematic name:
has been solved by simulated annealing from X-ray laboratory
   powder data and refined by Rietveld refinement without any restraints
   for non-H atoms.

2006-16 ??

Katz, MJ   Aguiar, PM   Batchelor, RJ   Bokov, AA   Ye, ZG   Kroeker, S
   Leznoff, DB
Structure and multinuclear solid-state NMR of a highly birefringent
   lead-gold cyanide coordination polymer
microcrystalline Pb[Au(CN)(2)](2) (2).
a structure is proposed on the basis of the NMR and X-ray powder data,


Stowasser, F   Renkenberger, C
Ab initio crystal structure determination of Bi6Rh12O29 from powder
   diffraction data
simulated annealing
Bi6Rh12O29    C2/m, Z = 4
laboratory X-ray powder diffraction data
with the software package    TOPAS


Kongshaug, KO    Fjellvag, H
Design of novel bilayer compounds of the CPO-8 type containing 1D channels
INORGANIC CHEMISTRY 45, 2006, 2424-2429.
   ([Zn(C8H5NO4)(ClOH8N2)(0.5)] .  3nH(2)O),
   ([Zn(C8H5NO4)(Cl2H10N2)(0.5)](n) .  2.5nH(2)O),
   ([Zn(C8H5NO4)(Cl2H12N2)(0.5)](n) .  2.5nH(2)O), and
   ([Zn(C8H5NO4)(C13H14N2)(0.5)](n) .  3nH(2)O),
The crystal structures of these porous high-temperature variants have been
   determined on the basis of powder X-ray diffraction data. All of the
   compounds show preferential adsorption of H-2 over N-2 at 77 K.


Ivashkevich, LS   Selevich, KA   Lesnikovich, AI   Selevich, AF   Lyakhov, AS
Two isostructural manganese(III) diphosphates, acid alpha-MnHP2O7 and
   double MnLiP2O7: crystal structure determination from X-ray powder
   diffraction data
Ab initio crystal structure determination of the a form of MnHP2O7 and
   Rietveld refinement of the MnLiP2O7 structure were performed using
   powder X-ray diffraction data.


Gomez-Alcantara, MM   Aranda, MAG   Olivera-Pastor, P   Beran, P
   Garcia-Munoz, JL   Cabeza, A
Layered and pillared metal carboxyethylphosphonate hybrid compounds
DALTON TRANSACTIONS iss 4, 2006, 577-585.
carboxyethylphosphonate hybrid materials:
Mn-II(O3PCH2CH2COOH)(H2O)-H-. (1),
solved ab initio from laboratory
   X-ray powder diffraction data and refined by the Rietveld method.
Al-III(OH)(3)(O3PCH2CH2CO2)(2)(.)3H(2)O (3)
solved ab initio from synchrotron X-ray powder diffraction data.


Larranaga, A   Mesa, JL   Pizarro, JL   Pena, A   Olazcuaga, R
  Arriortua, MI   Rojo, T
Synthesis and structural, spectroscopic and magnetic studies of two new
   polymorphs of Mn(SeO3) .  H2O
Mn(SeO3) H2O
solved from X-ray powder diffraction data.


Vigo, L   Risto, M   Jahr, EM   Bajorek, T   Oilunkaniemi, R
   Laitinen, RS   Lahtinen, M   Ahlgren, M
Isomerism in [MCl2(ERR ')(2)] (M = Pd, Pt; E = S, Se; R, R ' = Me, Ph)
CRYSTAL GROWTH & DESIGN 6, 2006, 2376-2383.
A series of thioether and selenoether complexes [MCl2(EPh2)(2)] and
   [MCl2(SMePh)(2)] (M = Pt, Pd; E = S, Se) have been prepared and
   characterized to explore the isomerism of the complexes in solution and
   in the solid state. The NMR spectroscopic information indicates that
   only one isomer is present in solution in case of the palladium
   complexes, while two isomers are formed in the case of most platinum
   complexes. Single-crystal X-ray structures of trans-[PdCl2(SPh2)(2)]
   (1t), trans-[PdCl2(SePh2)(2)] (2t), cis-[PtCl2(SePh2)(2)] (4c),
   trans-[PdCl2(SMePh)(2)] ( 5t), and trans-[PtCl2(SMePh)(2)] ( 7t) are
   reported and have been used as starting points for the X-ray powder
   diffraction structure determinations using simulated annealing method
   together with Rietveld refinement of the powder diffraction data. The
   presence of only trans- isomers in the solid phases was deduced in the
   case of [PdCl2(SPh2)(2)] and [PdCl2(SePh2)(2)] (1t and 2t,
   respectively). By contrast, the Rietveld refinement of the powder X-ray
   diffraction diagrams of [PtCl2(SPh2)(2)] and [PtCl2(SePh2)(2)]
   indicated the presence of both trans- and cis-isomers (3t, 3c and 4t,
   4c, respectively) with mixing ratios that are consistent with NMR
   spectroscopic information in solution. The density functional theory
   calculations using [MCl2(EMe2)(2)] as model complexes indicated that
   while the trans- isomers of the palladium complexes lie at
   significantly lower energy than the cis-isomers do, in the case of the
   platinum complexes the energy difference is smaller and decreases, as
   the chalcogen atom of the chalcogenoether ligand becomes heavier.


Hulme, AT   Fernandes, P   Florence, A   Johnston, A   Shankland, K
Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione 1-methylnaphthalene
The crystal structure of the title compound, C8H11N1O2.-0.5C(11)H(10),
   was solved by simulated annealing from laboratory X-ray powder
   diffraction data, collected at room temperature. Subsequent Rietveld
   refinement, using data collected to 1.51 angstrom resolution, yielded
   an R-wp value of 0.057. The compound crystallizes with two molecules of
   3-azabicyclononane-2,4- dione and one molecule of 1-methylnaphthalene
   in the asymmetric unit.


Llinas, A   Fabian, L   Burley, JC   van de Streek, J   Goodman, JM
Amodiaquinium dichloride dihydrate from laboratory powder diffraction
The title compound (systematic name: {5-[(7-chloroquinolinium4-yl)
   amino]-2-hydroxybenzyl} dimethylammonium dichloride dihydrate),
   C20H24ClN3O2+  .  2Cl (- .) 2H(2)O, has one
   amodiaquinium dication, two Cl- anions and two water molecules in the
   asymmetric unit. The crystal structure was solved by simulated
   annealing from laboratory X-ray powder diffraction data, with data
   collected at room temperature. Rietveld refinement of this model led to
   a final R-wp of 0.047 to 1.79 angstrom resolution. A three-dimensional
   network of hydrogen bonding links the amodiaquinium cations via water
   molecules and Cl- ions.


Martinetto, P   Terech, P   Grand, A   Ramasseul, R   Dooryhee, E   Anne, M
Molecular structure of a D-homoandrostanyl steroid derivative: Single
   crystal and powder diffraction analyses
JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 15127-15133.
The knowledge of the structure of a molecular crystal is frequently a
   prerequisite for the understanding of its solid state properties. Even
   though single-crystal diffractometry is the method of choice when it
   comes to crystal structure determination, methods using powder
   diffraction data become more and more competitive. There has been much
   recent interest in the development of a new generation of
   "direct-space" approaches that are particularly suited for molecular
   crystals. The crystallographic structure of a steroid derivative
   molecule (17,17-di-n-propyl-17a-aza-D-homo-5R-androstan-3,-ol) was
   obtained in two independent ways: from a single crystal by laboratory
   X-rays and from a polycrystalline powder by high-resolution synchrotron
   powder diffraction. The molecule crystallizes in the orthorhombic space
   group P2(1)2(1)2(1) (a) 6.5346, b) 17.6006 and c) 19.6978 angstrom).
   Hydrogen bonds form infinite chains of molecules parallel to the c axis.

2006-26  ??

Kubota, Y   Takata, M   Matsuda, R   Kitaura, R   Kitagawa, S   Kobayashi, TC
Metastable sorption state of a metal-organic porous material determined
   by in situ synchrotron powder diffraction


Duc, F    Gonthier, S   Brunelli, M   Trombe, JC
Hydrothermal synthesis and structure determination of the new vanadium
   molybdenum mixed oxide V1.1Mo0.9O5 from synchrotron X-ray powder
   diffraction data
AB A new vanadium molybdenum mixed oxide V1.1Mo0.9O5
   [V(V)(0.2)V(IV)(0.9)Mo(VI)(0.9)O-5] has been synthesized, as a pure
   phase, via hydrothermal methods in the presence of molybdic acid and
   vanadyl sulfate. Its crystal structure has been solved ab initio from
   high-resolution powder diffraction data collected at the ESRF beamline
   ID31. This compound crystallizes in the monoclinic symmetry, space
   group C2/m, with cell dimensions a = 12.1230(2) angstrom, b = 3.7168(1)
   angstrom, c = 4.0336(1) angstrom, beta = 90.625(3)degrees and Z = 2 per
   formula. The structure consists of double strings of VO5 square
   pyramids sharing edges and corners along [ 100] and [0 10], and more
   weakly bound along [001]. In this latter direction, the bond (V,Mo)-O =
   2.377 angstrom, while remaining long, leads for the first time to the
   interpenetration of the apical oxygens of the [(V,MO)(2)O-5](n) layers,
   resulting in a three-dimensional (3D) structure closely related to
   R-Nb2O5. This structure will be compared to the pure layer structure of
   V2O5 where this bond reaches 2.793 angstrom.


Hernandez, O   Knight, KS   Van Beek, W   Boucekkine, A
   Boudjada, A   PauluS, W   Meinnel, J
Phases II and IV of 1,3,5-trichloro-2,4,6-trimethylbenzene: Ab initio
   crystal structure determination by high-resolution powder diffraction
The hitherto unknown structures of stable crystal phases 11 and IV of
   undeuterated 1,3,5-trichioro-2,4,6-trimethylbenzene, TCM9H (phase 11,
   above T-III -> II= 314 K, and phase IV, below T-III -> IV similar or
   equal to 160 K, phase III in between) have been solved ab initio from
   powder synchrotron X-ray diffraction data, respectively, at 343 K by
   direct methods and at 50 K using a Monte-Carlo simulated annealing
   method. They have been then refined for perdeuterated TCM (TCM9D, same
   behaviour as TCM9H) against high-resolution powder neutron diffraction
   data at 343 and 2 K, respectively. Phase 11 is disordered (space group
   P2(1)/n, Z= 2, a = 15.12984(13) angstrom, b = 3.92080(3) angstrom, c =
   8.27786(8) angstrom, beta = 90.8374(8)degrees), whilst phase IV is
   ordered (space group P (1) over bar, Z= 2, a = 7.42872(5) angstrom, b =
   8.75731(6) angstrom, c = 8.76246(6) A, alpha = 59.8543(4)degrees, beta
   = 68.2959(5)degrees, gamma = 73.1654(6)degrees). The mechanisms driving
   both reconstructive phase transitions at T-III -> II and T-III -> IV
   are described at a microscopic level; it is shown that they involve
   rotations of the molecules (out-of-plane and in-plane, respectively,
   with regard to the molecular plane of phase 111) leading to huge atomic
   displacements up to 2.0 and 1.2 angstrom, respectively. The molecular
   conformation in phase IV is compared to the one obtained from DFT
   quantum chemistry calculations for an isolated molecule in order to
   extract the characteristics of the inter-molecular interactions and the
   deuteron nuclear densities are extracted at 2 K.


Serre, C   Millange, F   Devic, T   Audebrand, N   Van Beek, W
Synthesis and structure determination of new open-framework chromium
   carboxylate MIL-105 or Cr-III(OH) . {O2C-C-6(CH3)(4)-CO2}center
   dot nH(2)O
Two new three-dimensional chromium(III) dicarboxylate, MIL-105 or
   Cr-III(OH) . {O2C-C-6(CH3)(4)-CO2} .  nH(2)O, have been
   obtained under hydrothermal conditions, and their structures solved
   using X-ray powder diffraction data. Both solids are structural analogs
   of the known Cr benzenedicarboxylate compound (MIL-53). Both contain
   trans corner-sharing CrO4(OH)(2) octahedral chains connected by
   tetramethylterephthalate di-anions. Each chain is linked by the ligands
   to four other chains to form a three-dimensional framework with an
   array of 1D pores channels. The pores of the high temperature form of
   the solid, MIL-105ht, are empty. However, MIL-105ht re-hydrates at room
   temperature to finally give MIL-1051t with pores channels filled with
   free water molecules (It: low temperature form; ht: high temperature
   form). The thermal behaviour of the two solids has been investigated
   using TGA. Crystal data for MIL-105ht: monoclinic space group C2/c with
   a = 19.653(1) angstrom, b = 9.984(1) angstrom, c = 6.970(1) angstrom,
   beta = 110.67(1)degrees and Z = 4. Crystal data for MIL-1051t:
   orthorhombic space group Pnam with a = 17.892(1) angstrom, b = 11.
   165(1) angstrom, c = 6.916(1) angstrom and Z = 4.


Ibberson, RM
The low-temperature phase III structure and phase transition behaviour
   of cyclohexanone
The crystal structure of phase III of perdeuterocyclohexanone, C6D10O,
   has been determined at 5 K using high-resolution neutron powder
   diffraction. Below its melting point of 245 K cyclohexanone forms a
   plastic crystal in the space group Fm (3) over barm. On cooling below
   225 K the crystal transforms to the monoclinic phase III structure in
   the space group P2(1)/n. The orthorhombic phase II structure exists
   under high pressure, but the triple point for all three phases is close
   to atmospheric pressure. Details of the phase II structure are also
   reported at 4.8 kbar (273 K) and ambient pressure. The phase behaviour
   of the compound and isotope effects are discussed.


Mora, AJ   Brunelli, M   Fitch, AN   Wright, J   Baez, ME   Lopez-Carrasquero, F
Structures of (S)-(-)-4-oxo-2-azetidinecarboxylic acid and
   3-azetidinecarboxylic acid from powder synchrotron diffraction data
The crystal structures of the four-membered heterocycles
   (S)(-)-4-oxo-2-azetidinecarboxylic acid (I) and 3-azetidinecarboxylic
   acid (II) were solved by direct methods using powder synchrotron X-ray
   diffraction data. The asymmetry of the oxoazetidine and azetidine rings
   is discussed, along with the hydrogen bonding.


Damay, F   Carretero-Genevrier, A   Cousson, A   Van Beek, W
   Rodriguez-Carvajal, J   Fillaux, F
Synchrotron and neutron diffraction study of 4-methylpyridine-N-oxide
   at low temperature
The structure of 4-methylpyridine-N-oxide has been determined at 250,
   100 and 10 K by combined synchrotron (C6H7NO) and neutron (C6D7NO)
   powder diffraction experiments. At 250 K the space group is I4(1)/amd
   and the tetragonal unit cell [a = b = 7.941 (2), c = 19.600 (5)
   angstrom] contains eight equivalent molecules. At 100 K the structure
   is orthorhombic, with space group Fddd, a = 12.138 (2), b = 10.237 (2)
   and c = 19.568 (3) angstrom. The 16 equivalent molecules are rotated by
   about 8 degrees around the c axis with respect to positions at high
   temperature. At 10 K the best structural model corresponds to a
   tetragonal unit cell with the space group P4(1), a = b = 15.410 (2)
   angstrom and c = 19.680 (3) angstrom. The 32 molecules (eight molecules
   in the asymmetric unit) show complex reorientations around the three
   cell axes. Whereas at 250 and 100 K the deuterated methyl groups are
   largely disordered, at 10 K they are ordered in-phase along infinite
   chains parallel to a and b. Face-to-face methyl groups along c are in
   an eclipsed configuration. The structure at 10 K suggests that the
   manifold of rotational tunnelling transitions could be due to
   inequivalent lattice sites for crystallographically independent methyl


Hulme, AT   Fernandes, P   Florence, A   Johnston, A   Shankland, K
Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione form 2
A polycrystalline sample of a new polymorph of the title compound,
   C8H11NO2, was produced during a variable-temperature X-ray powder
   diffraction study. The crystal structure was solved at 1.67 angstrom
   resolution by simulated annealing from laboratory powder data collected
   at 250 K. Subsequent Rietveld refinement yielded an R-wp of 0.070 to
   1.54 angstrom resolution. The structure contains two molecules in the
   asymmetric unit, which form a C 2 2(8) chain motif via N-H  .
    .   .  O hydrogen bonds.


Cerny, R   Renaudin, G   Tokaychuk, Y   Favre-Nicolin, V
Complex intermetallic compounds in the Mg-Ir system solved by powder
ZEITSCHRIFT FUR KRISTALLOGRAPHIE Suppl. 23, part 2, 2006, 411-416.
The crystal structures of two new topologically close-packed
   intermetallic compounds, MgIr (Cmca, 25 atoms) and Mg2-xIr3+x (x=0.067,
   C2/m, 11 atoms) were fully characterized by high resolution synchrotron
   powder diffraction and global optimization of a structural model in
   direct space. The simulated annealing algorithm (in parallel tempering
   mode) and computer program Fox were used.


Akkari, H   Benard-Rocherulle, P   Merazig, H   Roisnel, T   Rocherulle, J
Hydrothermal synthesis, crystal structure and thermal behaviour of the
   first lanthanide sulfato-squarate, La-2(H2O)(4)(SO4)(2)(C4O4)
SOLID STATE SCIENCES 8, 2006, 704-715.
A new three-dimensional lanthanum(III) sulfate squarate,
   La-2(H2O)(4)(SO4)(2)(C4O4), has been synthesized hydrothermally with
   squaric acid at 180 degrees C and its structure has been solved by
   single-crystal X-ray diffraction methods. A relevant feature of this
   new material is that it constitutes the first member of a family of
   hybrids based on this composition. It crystallizes in the monoclinic
   space group P(2)1/n, with a = 6.5965(1) angstrom, b = 10.9595(3)
   angstrom, c = 9.6633(2) angstrom, beta = 96.457(1)degrees, V =
   694.17(3) angstrom(3), Z = 2. Its framework is built up from dimers of
   O-O edged-sharing nine-coordinated LaO7(H2O)(2) polyhedra described as
   monocapped square antiprisms. The linking of the binuclear La species
   by sulfate groups occurs in planes parallel to (11(1) over bar) and
   subsequently generates inorganic layers showing cavities. The stacking
   of them along the a-axis generates tunnels filled with bonded water
   molecules and squarate moieties. The three-dimensionality is ensured by
   one sulfate oxygen atom and the C-4-cycles. Thus, according to this
   structural description, the material presents a novel 3D-type structure
   in the field of the mixed anionic lanthanide compounds. The thermal
   behavior of La-2(H2O)(4)(SO4)(2)(C4O4) has been investigated using
   TG-DTA and X-ray thermodiffractometry showing that this precursor of
   crystallized lanthanum oxide at 900 degrees C is stable up to 150
   degrees C.


Barrio, M   Pardo, LC   Tamarit, JL   Negrier, P   Salud, J
   Lopez, DO   Mondieig, D
Two-component system CCl4 + (CH3)(3)CBr: Extrema in equilibria
   involving orientationally disordered phases
JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 12096-12103.
Phase equilibria involving orientationally disordered (OD) and liquid
   phases of the two-component system between carbon tetrachloride (CCl4)
   and 2-methyl-2-bromomethane ((CH3)(3)CBr) have been determined by means
   of X-ray powder diffraction and thermal analysis techniques from 210 K
   up to the liquid state. The isomorphism relation between the OD stable
   face-centered cubic (FCC) phase of (CH3)(3)CBr and the metastable FCC
   phase of CCl4 has been demonstrated throughout the continuous evolution
   of the lattice parameters and the existence of the two-phase
   equilibrium [FCC + L] for the whole range of composition, despite the
   monotropy of the FCC phase for the CCl4 component with respect to its
   OD rhombohedral (R) stable phase. A continuous series of OD R mixed
   crystals is found, which confirms the R lattice symmetry of the OD
   phase II of (CH3)(3)CBr, for which the crystallographic results have
   been long-time misinterpreted. X-ray patterns of such a phase were
   indexed according to the recent single-crystal results obtained by
   Rudman (Rudman, R. J. Mol. Struct. 2001, 569, 157). In addition, some
   experimental evidences are given to confirm the number of molecules per
   unit cell (Z = 21). The thermodynamic assessment reproduces coherently
   the phase diagram for the stable [R + L] and [R + FCC] two-phase
   equilibria as well as for the partially metastable [FCC + L] two-phase
   equilibrium and provides a set of data for the thermodynamic properties
   of nonexperimentally available phase transitions of pure components.
   Surprisingly, the phase equilibrium involving R and FCC OD phases
   appears as one of the very few showing a solid-solid equilibrium with
   two extremes.


Ibberson, RM   Yamamuro, O   Tsukushi, I
The crystal structures and phase behaviour of cyclohexene oxide
CHEMICAL PHYSICS LETTERS 423, 2006, 454-458.
The phase 11 crystal structure of perdeuterated cyclohexene oxide has
   been solved from neutron powder diffraction data at 5 K utilising a
   simulated annealing method. The structure is triclinic, space group P1,
   with a unit cell volume of 268 angstrom(3). The refined molecular
   conformation is shown to be in close agreement with recent ab initio
   calculations. The p-T phase diagram determined using DTA and details of
   the phase I structure are also reported.


Fernandes, P   Florence, AJ   Shankland, K   Shankland, N   Johnston, A
Powder study of chlorothiazide N,N-dimethyl-formamide solvate
The crystal structure of the title compound [systematic name:
   1,1-di-oxide-N,N-dimethylformamide (1/1)], C7H6ClN3O4S2.C3H7NO, was
   solved by simulated annealing from laboratory X-ray powder diffraction
   data collected at 100 K. Subsequent Rietveld refinement, using data
   collected to 1.5 angstrom resolution, yielded an R-wp of 0.050.
   Hydrogen bonds to N,N-dimethylformamide form the rungs of a ladder
   motif, which is further stabilized by a pi(...)halogen dimer
   interaction. The benzene rings in adjacent ladders engage with each
   other in an offset face-to-face pi-pi interaction.


Tokaychuk, YO   Filinchuk, YE   Fedorchuk, AO   Kozlov, AY   Mokra, IR
New representatives of the linear structure series containing empty
   Ga/Ge cubes in the Sm-Ga-Ge system
New ternary intermetallic compounds Sm2Ga7-xGex (x = 5.2-6.1) and
   Sm4Ga11-xGex (x = 5.76-8.75) were synthesized and their crystal
   structures were determined by X-ray powder diffraction at compositions
   Sm2Ga1.8Ge5.2 and Sm4Ga5.24Ge5.76, Sm2Ga1.8Ge5.2 crystallizes with the
   Ce-2(Ga0.1Ge0.9)(7) type of structure (space group Cmce, Pearson code
   oS80-8.00, a = 8.46216(13), b = 8.15343(13) b = 21.1243(3) angstrom, Z
   = 8), while Sm4Ga5.24Ge5.76 exhibits a new structure (space group Cmmm.
   Pearson code oS52-22.00. a = 4.21038(4). b = 35.8075(3), c = 4.14023(4)
   angstrom, Z = 2). Both structures are the members of the linear
   intergrowth structure series built up from segments of BaAl4. AlB2 and
   alpha-Po structure types. Their Ga/Ge networks contain characteristic
   empty cubes with one side capped by an atom subjected to an intrinsic
   displacive disorder. A model of Ga/Ge localization was suggested the
   basis of crystal-chemical analysis.


Surble, S   Serre, C   Millange, F   Ferey, G
Structural changes upon dehydration of Pr-(III)(H2O){C6H3-(CO2)(3)} or
   MIL-81: A new three-dimensional praseodymium
   1,2,4-benzenetricarboxylate with a one dimensional inorganic sub-network
SOLID STATE SCIENCES 8, 2006, 413-417.
A new three-dimensional lanthanide(III) tricarboxylate, MIL-81(1) or
   Pr-(III)(H2O)(C6H3-(CO2)(3)) has been obtained under hydrothermal
   conditions. Its three-dimensional structure, which has been determined
   using X-ray powder diffraction data, is built-up from edge-sharing
   chains of nine coordinated prascodymium(III) capped square antiprisms
   linked through 1,2,4-Benzenetricarboxylate (1,2,4-BTC) moieties. Its
   thermal behaviour has been investigated using TGA and X-ray
   thermodiffractometry and reveals that dehydration is followed by an
   irreversible structural change giving the solid MIL-81ht or
   Pr-(III)(C6H3-(CO2)(3)) with both a change in the environment of the
   rare earth and in the connection mode of the carboxylate.
   Crystal data for MIL-81: monoclinic space group P2(1) with a =
   10.272(1) angstrom, b = 7.057(l) angstrom, c = 6.232(1) angstrom, c=
   93.668(4)degrees and Z = 2. Crystal data for MIL-81ht: triclinic space
   group P-1 with a = 9.864(1) angstrom, b = 7.054(1) angstrom, C =
   5.784(1) angstrom, alpha = 90.862(9)degrees,beta = 92.439(6)degrees,
   gamma = 91.594(8)degrees and Z = 2.


Wu, L   Chen, XL   Zhang, Y   Kong, YF   Xu, JJ   Xu, YP
Ab initio structure determination of novel borate NaSrBO3
A novel orthoborate, NaSrBO3, has been Successfully synthesized by
   standard solid-state reaction, and the crystal structure has been
   determined from powder X-ray diffraction data. It crystallizes in the
   monoclinic space group P2(1)/c with lattice parameters: a = 5.32446(7)
   angstrom, b = 9.2684(l) angstrom, 6.06683(8) angstrom, beta =
   100.589(l)degrees. The fundamental building units are isolated BO3
   groups, which are parallelly distributed along two different
   directions. Because of the anisotropic polarizations of planar BO3
   groups, a considerable birefringence can be expected in it. The Na
   atoms are six-coordinated with O atoms to form octahedra, and the Sr
   atoms are nine-coordinated, forming tri-capped trigonal prisms. Those
   polyhedra connect with each other by bridging-oxygen atoms, forming
   infinite three-dimensional network, which indicates that the cleaving
   problem is expected to be overcome during the Course of single-crystal
   growth. The infrared spectrum has been measured, and the result is
   consistent with the crystallographic study. Moreover, a comparison of
   the new structure type with the other known orthoborates is presented


Wu, L   Chen, XL   Xu, YP   Sun, YP
Structure determination and relative properties of novel noncentrosym
   metric borates MM '(4)(BO3)(3) (M = Na, M ' = Ca and M = K, M ' = Ca,
INORGANIC CHEMISTRY 45, 2006, 3042-3047.
A series of novel noncentrosymmetric borates, MM'(4)(BO3)(3) (M = Na,
   M' = Ca; M = K, M' = Ca, Sr), have been successfully synthesized via a
   standard solid-state reaction. The crystal structures have been
   determined by the SDPD (structure determination from powder
   diffraction) method. They crystallize in the noncentrosymmetric space
   group Ama2 with the following lattice parameters: a = 10.68004(11)
   angstrom, b = 1 1.28574(11) angstrom, c = 6.48521(6) angstrom for
   NaCa4(BO3)(3); a = 10.63455(10) angstrom, b = 11,51705(11) angstrom, c
   = 6.51942(6) angstrom for KCa4(BO3)(3); and a = 11.03843(8) angstrom, b
   = 11.98974(9) angstrom, c = 6.88446(5) angstrom for KSr4(BO3)(3). The
   fundamental building units are isolated BO3 anionic groups. Their
   second harmonic generation (SHG) coefficients were one-half
   (NaCa4(BO3)(3)), one-third (KCa4(BO3)(3)), and two-thirds
   (KSr4(BO3)(3)) as large as that of KH2PO4 (KDP). The infrared and
   UV-vis spectra of the three compounds are discussed. Moreover, a
   comparison of the structures of these novel compounds and three other
   novel cubic compounds with the same formula, MM'(4)(BO3)(3) (M = Li, M'
   = Sr; M = Na, M' = Sr, Ba), is presented here.


Serre, C   Groves, JA   Lightfoot, P   Slawin, AMZ   Wright, PA
   Stock, N   Bein, T   Haouas, M   Taulelle, F   Ferey, G
Synthesis, structure and properties of related microporous N,N
   '-piperazinebismethylenephosphonates of aluminum and titanium
CHEMISTRY OF MATERIALS 18, 2006, 1451-1457.
A porous framework titanium(IV) N,N'-piperazinebis
   (methylenephosphonate) (MIL-91(Ti)) and its aluminum analogue have been
   prepared under hydrothermal conditions (MIL = Material Institut
   Lavoisier). The structure of the aluminum analogue, AlOH(H2L) .
   nH(2)O (eta similar to 3, L = O3P-CH2-NC4H8N-CH(2)Z, PO3) was solved
   from a small single crystal and refined against laboratory powder X-ray
   diffraction data. The structure of the titanium form (TiO(H2L)-nH(2)O
   (n similar to 4.5)) was determined using the structure of the aluminum
   form as a starting model and refining it against laboratory X-ray data.
   Their structures are built up from trans corner-sharing chains of TiO6
   or AlO6 octahedra linked together in two directions via the
   diphosphonate groups. In each case this gives rise to a
   three-dimensional hybrid network with small channels along the b axis,
   filled with free water molecules. Thermogravimetric analysis and X-ray
   thermodiffractometry of the samples reveal that water is lost
   reversibly below 423 K and that both structures are stable up to 463 K.
   Dehydration gives porous solids (pore size similar to 3.5 x 4.0
   angstrom(2)) which adsorb nitrogen at 77 K to give Langmuir surface
   areas close to 500 m(2) .  g(-1). Crystal data for MIL-91 (Ti)
   are as follows: space group C2/m. (No. 12) with a = 19.415(2) angstrom,
   b = 7.071 (1) angstrom, c = 11.483(1) 92.78(1)degrees, V 1574.70(1)
   angstrom(3), and Z = 2. Crystal Data for MIL-91 (Al) are as follows:
   space group C2/m (No. 12) With a = 18.947(2) angstrom, b = 6.915(1)
   angstrom, c = 11.295(1) angstrom, beta = 90.45(1)degrees, and V =


Hemono, N   Rocherulle, J   Le Floch, M   Bureau, B
Synthesis, characterization and devitrification behaviour of an yttrium
   containing boroaluminate glass
The glass forming region in the B2O3-Al2O3-Y2O3 composition diagram has
   been determined by a melting and quenching procedure at temperatures up
   to 1800 degrees C. Different physical characteristics (density,
   coefficient of thermal expansion, glass transition and crystallization
   peak temperatures) have been determined for a
   35B(2)O(3)-40Al(2)O(3)-25Y(2)O(3) glass composition (in mot.%). By
   using a predictive model and some NMR structural data, different
   elastic moduli (Young's modulus, bulk modulus, shear modulus and
   Poisson's ratio) have been calculated. The devitrification behaviour
   has also been studied. Internal crystallization is the dominant
   mechanism and a new (Y, Al)BO3 ternary phase has been characterized by
   X-ray powder diffraction. The temperature and time nucleation
   dependence have been determined from DTA experiments as well as the
   crystallization kinetics (i.e. the Avrami exponent and the activation
   energy for crystal growth).


Ibberson, RM   Telling, MTF   Parsons, S
Structure determination and phase transition behaviour of dimethyl
The crystal structures of phase I and phase II of dimethyl sulfate,
   (CH3O)(2)SO2, have been determined using complementary high-resolution
   neutron powder and single-crystal X-ray diffraction techniques. Below
   its melting point of 241 K dimethyl sulfate crystallizes in an
   orthorhombic structure (I) in the space group Fdd2. On cooling below
   similar to 175 K the crystal transforms to a monoclinic structure ( II)
   in the space group I2/a. The molecule is located on a twofold axis (Z'
   = 1/2) in both structures. The phase transition is of first order with
   strong hysteresis. The phase transition results in changes to both the
   intra- and the intermolecular coordination environment.


Haynes, DA   Van de Streek, J   Burley, JC   Jones, W   Motherwell, WDS
Pamoic acid determined from powder diffraction data
The title compound [ systematic name:
   4,4'-methylenebis(3-hydroxy-2-naphthoic acid)], C23H16O6, has one
   half-molecule in the asymmetric unit. The molecular twofold rotational
   axis about the central C atom is preserved on crystallization. A chain
   formed by R-2(2)(8) hydrogen bonds runs along the c axis and an
   intramolecular O-H  .   .   .  O=C-OH hydrogen
   bond is also formed. The crystal structure was solved by simulated
   annealing from laboratory X-ray powder diffraction data, with data
   collected at room temperature. Rietveld refinement of this model led to
   a final R-wp value of 0.0391 at 1.39 angstrom resolution.


Harper, JK   Grant, DM   Zhang, YG   Lee, PL   Von Dreele, R
Characterizing challenging microcrystalline solids with solid-state NMR
   shift tensor and synchrotron X-ray powder diffraction data: Structural
   analysis of ambuic acid
Synchrotron X-ray powder diffraction and solid-state C-13 NMR shift
   tensor data are combined to provide a unique path to structure in
   microcrystalline organic solids. Analysis is demonstrated on ambuic
   acid powder, a widely occurring natural product, to provide the
   complete crystal structure. The NMR data verify phase purity, specify
   one molecule per asymmetric unit, and provide an initial structural
   model including relative stereochemistry and molecular conformation. A
   refinement of X-ray data from the initial model establishes that ambuic
   acid crystallizes in the P2(1) space group with unit cell parameters a
   = 15.5047(7), b = 4.3904(2), and c = 14.1933(4) angstrom and beta =
   110.3134(3)degrees. This combined analysis yields structural
   improvements at two dihedral angles over prior NMR predictions with
   differences of 103 degrees and 37 degrees found. Only minor differences
   of +/- 5.5 degrees, on average, are observed at all remaining dihedral
   angles. Predicted hydroxyl hydrogen-bonding orientations also fit NMR
   predictions within +/- 6.9 degrees. This refinement corrects chemical
   shift assignments at two carbons and reduces the NMR error by similar
   to 16%. This work demonstrates that the combination of long-range order
   information from synchrotron powder diffraction data together with the
   accurate shorter range structure given by solid-state NMR measurements
   is a powerful tool for studying challenging organic solids.


Burley, JC   van de Streek, J   Stephens, PW
Ampicillin trihydrate from synchrotron powder diffraction data
The crystal structure of ampicillin trihydrate {systematic name:
   6-[D(-)-alpha-aminophenylacetamido]penicillanic acid trihydrate},
   C16H19N3O4S . 3H(2)O, a broad-spectrum beta-lactam antibiotic
   of the aminopenicillin type, has been determined from synchrotron X-ray
   powder diffraction data. The three water molecules form an infinite
   hydrogen-bonded chain through the crystal structure, with hydrogen
   bonds to the NH3+, COO-, C=O and NH groups of the ampicillin molecules.


Bowman, A   Smith, RI   Gregory, DH
Synthesis and structure of the ternary and quaternary strontium nitride
   halides, Sr2N(X, X ') (X, X ' = Cl, Br, I)
A number of new, layered nitride mixed halides have been synthesised in
   the quaternary phase systems Sr-N-Cl-Br and Sr-N-Br-I. The variation in
   structure with composition has been investigated by powder X-ray and
   powder neutron diffraction techniques and the structure of strontium
   nitride iodide, Sr2NI, has been determined for the first time
   (rhombohedral space group R-3m, a = 4.0103(1)angstrom, c =
   23.1138(2)angstrom, Z = 3). A continuous solid solution exists between
   Sr2NCl and Sr2NBr with intermediate compounds adopting the same
   anti-alpha-NaFeO2 structure (rhombohedral space group R-3m) as the
   ternary end members. A similar smooth and linear relationship between
   structure and composition is seen from Sr2NBr to Sr2NI and hence cubic
   close packing of metal-nitrogen layers is adopted regardless of halide,
   X(X'). While nitride and halide anions occupy distinct crystallographic
   sites, there is no ordering of the halides in the quaternary materials
   irrespective of stoichiometry or temperature (between 3 and 673 K).


Avila-Godoy, R   Mora, AJ   Acosta-Najarro, DR   Delgado, GE
   Lopez-Rivera, SA   Fitch, AN   Mora, AE   Steeds, JW
Structure of the quaternary alloy Zn0.6Mn0.4In2S4 from synchrotron
   powder diffraction and electron transmission microscopy
The aim of the present work was to determine the structure of the
   quaternary alloy Zn0.6Mn0.4In2S4 and to locate the Mn2+. This was
   accomplished by means of powder synchrotron X-ray diffraction,
   high-resolution microscopy and convergent-beam electron diffraction
   (CBED). The powder X-ray diffraction pattern was indexed in a
   rhombohedral cell, with cell constants a = 3.875 (2), c = 37.208 (4)
   angstrom, and possible space groups R(3) over bar m or R3m. Rietveld
   refinements using different cationic arrangements in these space groups
   were performed. A model in space group R3m, in which the tetrahedral
   and octahedral sites were occupied by different proportions of Zn, Mn
   and In atoms, gave the best result. The Rietveld refinement of this
   model led to figures of merit R-wp = 9.8%, R-p = 9.1% and chi(2) =
   11.1. Selected-area electron diffraction patterns and high-resolution
   transmission electron micrographs along [001] reveal the rhombohedral
   configuration. CBED patterns perpendicular to [001], showing the
   distinctive 3m symmetry, confirmed space group R3m and the breaking of
   the centrosymmetry of the parent compound, ZnIn2S4.

2006-51  ??

Chotard, JN   Filinchuk, Y   Revaz, B   Yvon, K
Isolated [Ni2H7](7-) and [Ni4H12](12-) ions in La2MgNi2H8

2006-52  ??

Pokhodnya, KI   Bonner, M   Her, JH   Stephens, PW   Miller, JS
Magnetic ordering (T-c=90 k) observed for layered [Fe-II(TCNE center
   dot-)(NCMe)(2)](+)[(FeCl4)-Cl-III](-) (TCNE = tetracyanoethylene)


Ivashkevich, LS   Lyakhov, AS   Gaponik, PN   Degtyarik, MM
   Ivashkevich, OA   Tiutiunnikov, SI   Efimov, VV
An X-ray powder investigation of
   catena-poly[copper(II)-di-mu-chloro-kappa(4)1 :
   2Cl-mu-1,5-dimethyl-1H-tetrazole-kappa N-2(3): N-4]
The crystal structure of the polymeric title complex,
   [CuCl2(C3H6N4)](n), has been solved from laboratory X-ray powder
   diffraction data collected at room temperature. The structural model
   obtained was refined with the Rietveld method using geometric soft
   restraints. There are two Cu atoms, two Cl atoms and one
   1,5-dimethyltetrazole ligand in the asymmetric unit. Both Cu atoms lie
   on inversion centres and adopt essentially elongated octahedral
   coordination. Within the octahedra, the elongated axial positions are
   occupied by Cl atoms, while two Cl and two N atoms (N3 and N4 of the
   tetrazole ring) are in equatorial sites. Each Cl atom forms an
   asymmetric bridge between neighbouring Cu atoms, which are also bridged
   via the N3-N4 bond of the tetrazole ring. These bridges result in the
   formation of polymeric chains, running along the a axis, with weak C H
    .   .   .  Cl hydrogen bonds crosslinking the


Tyutyunnik, AP   Zubkov, VG   Tarakina, NV   Krasil'nikov, VN
   Perelyaeva, LA   Baklanova, IV   Svensson, G
Synthesis, crystal structure and vibrational spectra of KCrV2O7 and
SOLID STATE SCIENCES 8, 2006, 1344-1352.
KCrV2O7 and RbCrV2O7 have been synthesized and their crystal structures
   have been determined using X-ray and neutron powder diffraction
   techniques. The phases crystallizes in space group P2/c with unit cell
   parameters for KCrV2O7: a = 7.9526(l) angstrom, b = 4.87543(5)
   angstrom, c = 6.89 10(1) angstrom and beta =101. 162(1)degrees and
   RbCrV2O7: a = 8.2361 (1) angstrom, b = 4.89480(4) angstrom, c =
   6.8980(l) angstrom and beta = 100.893 (1)degrees. The unit cell was
   confirmed by selected area electron diffraction studies. The crystal
   structure consists of two-dimensional CrV2O7- slabs parallel to the
   (100)-plane, formed from zigzag chains of face- and edge-sharing VO6
   octahedra connected through CrO6-octahedra. The VO6 Octahedra are very
   distorted including a short VO-vanadyl unit. The alkaline metal ions
   placed in the inter-slab space have coordination number 10+2 forming
   distorted triangular orthobicupolas. The infrared and Raman spectra of
   the compounds are presented and discussed.

2006-55  ???

Heines, P   Keller, HL   Armbruster, M   Schwarz, U   Tse, J
Pressure-induced internal redox reaction of Cs-2[PdI4]  .  I-2,
   Cs-2[PdBr4]  .  I-2, and Cs-2[PdCl4]  .  I-2
INORGANIC CHEMISTRY 45, 2006, 9818-9825.
The pressure-induced redox reaction within the system Cs-2[Pd-2 + I-4],
   I-2/Cs-2[Pd4+ I-6] was investigated by means of powder X-ray
   diffraction. Analogous high-pressure X-ray diffraction experiments were
   performed on the isostructural compounds Cs-2[PdX4] .  I-2 (X =
   Cl, Br). Additionally, the phase transition of Cs-2[PdBr4] .
   I-2 to Cs-2[PdBr4I2] was characterized by means of Raman scattering
   experiments as well as theoretical calculations based on density
   functional theory. On the basis of experimentally determined crystal
   structure data, a pathway for the topology of the redox reactions was
   developed and outlined.


Fortes, AD
The crystal structure of methanol monohydrate (CD3OD  .  D2O) at
   160 K from powder neutron diffraction
CHEMICAL PHYSICS LETTERS 431, 2006, 283-288.
The structure of methanol monohydrate at 160 K has been solved from
   powder neutron diffraction data by ab initio methods. The crystal is
   orthorhombic, space-group Cmc2(1) (Z = 4) with unit cell dimensions a =
   4.64910(2) angstrom, b = 14.08464(7) angstrom, c = 4.69358(1) angstrom
   V = 307.340(2) angstrom(3) (rho(calc) = 1212.29(1) kg m(-3)) at 160 K.
   The structure consists of water-water chains, linked by ordered
   hydrogen bonds extending along the c-axis, which cross link
   methanol-water chains with disordered hydrogen bonds along the a-axis.
   These perpendicular chains form sheets which are stacked parallel to
   the b-axis.


Nielsen, RKB   Kongshaug, KO   Fjellvag, H
Syntheses, crystal structures and thermal properties of 3D coordination
   polymers assembled from 1,4,5,8-naphthalenetetracarboxylic acid
SOLID STATE SCIENCES 8, 2006, 1237-1242.
Two new coordination polymers based on
   1,4,5,8-naphthalenetetracarboxylate (ntc) has been prepared by
   hydrothermal methods. Their crystal structures have been determined
   from synchrotron powder X-ray diffraction data. Ca-2(Cl4H4O8)(H2O)(2),
   CPO-13, is built around infinite chains kof seven coordinated calcium
   atoms. Zn-2(C14H4O8)(H2O)(2), CPO-14, is isostructural with
   Mn-2(C14H4O8)(H2O)(2), and is built around infinite chains of corner
   sharing Zn octahedra. Crystal data for CPO-13: Triclinic space group
   P-1, with a = 5.820, b = 6.759, c = 10.168 angstrom, alpha = 72.32
   degrees, beta = 86.09 degrees, gamma = 107.74 degrees, V = 357.310
   angstrom(3) and Z = 1. Crystal data for CPO-14: Orthorhombic space
   group Pbam, with a = 9.773, b = 7.060, c = 9.879 angstrom, V = 681.729
   angstrom(3) and Z = 2. The thermal properties were investigated for
   both compounds. An unusual anisotropic thermal expansion for CPO-14 is
   caused by the carboxylate groups of the me anions gradually bending
   away from each other.


Floquet, S   Guillou, N   Negrier, P   Riviere, E   Boillot, ML
The crystallographic phase transition for a ferric thiosemicarbazone
   spin crossover complex studied by X-ray powder diffraction
NEW JOURNAL OF CHEMISTRY 30, 2006, 1621-1627.
The crystal structure of a spin-transition compound, namely the
   thiosemicarbazone ferric complex Li[Fe(5BrThsa)(2)] .  H2O, was
   solved from powder X-ray diffraction data at temperatures where the
   high-spin (373 K) and low-spin (150 K) phases prevail. The methodology
   is based on traditional approaches (direct methods) combined with
   direct space strategy. Both phases crystallise in the monoclinic system
   P2(1)/c. At 373 K, the characteristics of the [FeN2O2S2] coordination
   core are consistent with those reported for high-spin iron(III)
   thiosemicarbazone complexes: a distorted coordination polyhedron and
   non-equivalent metal-ligand bond lengths. When the temperature is
   reduced to 150 K, a decrease of the beta angle from ca. 101 degrees
   (373 K) to ca. 901 (150 K) is the only major modi. cation of the cell
   parameters. The low-spin molecular structure reveals significant
   differences in bond lengths and bond angles compared to the high-spin
   structure. Finally, an extended hydrogen-bond network is implicated in
   the cooperative phase transition, as supported by strong intermolecular
   contacts between the ferric complexes and the water molecules and the
   crystallographic phase transition is associated with pronounced lattice


Surble, S   Millange, F   Serre, C   Duren, T   Latroche, M   Bourrelly, S
   Llewellyn, PL   Ferey, G
Synthesis of MIL-102, a chromium carboxylate metal-organic framework,
   with gas sorption analysis
A new three-dimensional chromium(III) naphthalene tetracarboxylate,
   (Cr3O)-O-III(H2O)(2)F{C10H4-(CO2)4}(1.5).6H(2)O (MIL-102), has been
   synthesized under hydrothermal conditions from an aqueous mixture of
   Cr(NO3)(3).9H(2)O, naphthalene-1,4,5,8-tetracarboxylic acid, and HF.
   Its structure, solved ab initio from X-ray powder diffraction data, is
   built up from the connection of trimers of trivalent chromium octahedra
   and tetracarboxylate moieties. This creates a three-dimensional
   structure with an array of small one-dimensional channels filled with
   free water molecules, which interact through hydrogen bonds with
   terminal water molecules and oxygen atoms from the carboxylates.
   Thermogravimetric analysis and X-ray thermodiffrac-tometry indicate
   that MIL-102 is stable up to similar to 300 degrees C and shows
   zeolitic behavior. Due to topological frustration effects, MIL-102
   remains paramagnetic down to 5 K. Finally, MIL-102 exhibits a hydrogen
   storage capacity of similar to 1.0 wt% at 77 K when loaded at 3.5 MPa
   (35 bar). The hydrogen uptake is discussed in relation with the
   structural characteristics and the molecular simulation results. The
   adsorption behavior of MIL-102 at 304 K resembles that of small-pore
   zeolites, such as silicalite. Indeed, the isotherms of CO2, CH4, and
   N-2 show a maximum uptake at 0.5 MPa, with no further significant
   adsorption up to 3 MPa. Crystal data for MIL-102: hexagonal space group
   P (6) over bar (No. 169), a = 12.632(1) angstrom, c = 9.622(1) angstrom.

van Mechelen, JB   Peschar, R   Schenk, H
Structures of mono-unsaturated triacylglycerols. I. The beta(1)
The crystal structures of the beta(1) polymorphs of monounsaturated
   triacylglycerols have been solved from high-resolution laboratory and
   synchrotron powder diffraction data for five pure compounds, the
   1,3-dimyristoyl-2-oleoylglycerol (beta 1-MOM),
   1,3-dipalmitoyl-2-oleoylglycerol (beta(1)-POP),
   1,3-distearoyl-2-oleoylglycerol (beta(1)-SOS),
   1-palmitoyl-2-oleoyl-3-stearoylglycerol (beta(1)-POS),
   1-stearoyl-2-oleoyl-3-arachidoylglycerol (beta 1-SOA) and three
   mixtures: the co-crystallized 1:1 molar mixture of SOS and POP
   [beta(1)-SOS/POP (1:1)] and two cocoa butters from Bahia and Ivory
   Coast, both in their beta-VI (= beta 1) polymorph. All eight beta 1
   structures crystallized in the space group (P2(1)/n) and have two short
   cell axes (5.44-5.46 and 8.18-8.22 A), as well as a very long b axis
   (112-135 A). The dominant-zone problem in the indexing of the powder
   patterns was solved with the special brute-force indexing routine
   LSQDETC from the POWSIM program. Structures were solved using the
   direct-space parallel-tempering method FOX and refined with GSAS. Along
   the b axis, alternations of inversion-centre- related 'three- packs'
   can be discerned. Each 'three-pack' has a central oleic zone, with
   oleic acyl chains of the molecules being packed together, that is
   sandwiched between two saturated-chain zones. The conformation of the
   triacylglycerol molecules is relatively 'flat' because the least-square
   planes through the saturated chains and those through the saturated
   parts of the olein chain are parallel. The solution of the beta 1
   structures is a step forward towards understanding the mechanism of
   fat-bloom formation in dark chocolate and has led to a reexamination of
   the beta(2) structural model.


van Mechelen, JB   Peschar, R   Schenk, H
Structures of mono-unsaturated triacylglycerols. II. The beta(2)
An improved crystal structure model has been established for the
   beta(2) polymorph of the symmetric mono-unsaturated triacylglycerol
   1,3-distearoyl-2-oleoylglycerol (SOS) and the equivalent beta-V
   polymorph of Ivory Coast cocoa butter. In addition, the crystal
   structures of the beta(2) polymorphs are reported for the
   triacylglycerols 1,3-dipalmitoyl-2-oleoylglycerol (POP) and
   1-palmitoyl-2-oleoyl-3-stearoylglycerol (POS), which are, together with
   SOS, the major components of cocoa butter, and that of
   1-stearoyl-2-oleoyl-3-arachidoylglycerol (SOA). The existence of beta
   2-POS and beta 2-SOA has not been previously reported in the
   literature. All structures have been solved from high-resolution
   laboratory or synchrotron powder diffraction data with the direct-space
   parallel-tempering program FOX and refined with the Rietveld module of
   GSAS. All compounds crystallize in similar monoclinic unit cells (Cc)
   with very long b axes (> 127 A). The oleic chains are packed together
   and sandwiched between saturated chain layers, forming acyl-chain
   three-packs. An analysis of the beta(2) polymorphs and beta(1)
   polymorphs [van Mechelen et al. (2006). Acta Cryst. B62, 1121-1130]
   shows that they contain the same three-packs and differ only in the
   symmetry relation between the three-packs. The three- pack build- up
   provides an explanation of the mechanism of the phase transition that
   causes the formation of fat bloom on dark chocolate.

Udovic, M   Valant, M   Jancar, B   Suvorov, D   Meden, A   Kocevar, A
Phase formation and crystal-structure determination in the
   Bi2O3-TiO2-TeO2 system prepared in an oxygen atmosphere
Using X-ray diffraction analysis and scanning electron microscopy it
   was revealed that in an atmosphere of flowing oxygen in the temperature
   range 700 degrees-800 degrees C, three new compounds are formed in the
   Bi2O3-TiO2-TeO2 pseudoternary system. These compounds are Bi2Ti3TeO12,
   Bi2TiTeO8, and Bi6Ti5TeO22, and all the compounds include Te6+. All
   three crystal structures were solved and refined using X-ray powder
   diffraction data. Based on the results of the phase formation, a
   solid-state compatibility diagram is proposed.

Gonen, ZS   Paluchowski, D   Zavalij, P   Eichhorn, BW   Gopalakrishnan, J
Reversible cation/anion extraction from K2La2Ti3O10: Formation of new
   layered titanates, KLa2Ti3O9.5 and La2Ti3O9
INORGANIC CHEMISTRY 45, 2006, 8736-8742.
A new soft-chemical transformation of layered perovskite oxides is
   described wherein K2O is sequentially extracted from the
   Ruddlesden-Popper (R-P) phase, K2La2Ti3O10 (I), yielding novel
   anion-deficient KLa2Ti3O9.5 (II) and La2Ti3O9 (III). The transformation
   occurs in topochemical reactions of the R-P phase I with PPh4Br and
   PBu4Br (Ph = phenyl; Bu = n-butyl). The mechanism involves the
   elimination of KBr accompanied by decomposition of PR4+ (R = phenyl or
   n-butyl) that extracts oxygen from the titanate. Analysis of the
   organic products of decomposition reveals formation of Ph3PO, Ph3P, and
   Ph-Ph for R = phenyl, and Bu3PO, Bu3P along with butane, butene, and
   octane for R = butyl. The inorganic oxides II and III crystallize in
   tetragonal structures (II: P4/mmm, a = 3.8335(1) angstrom, c =
   14.334(1) angstrom; III: /4/ mmm, a = 3.8565(2) angstrom, c = 24.645(2)
   angstrom) that are related to the parent R-P phase. II is isotypic with
   the Dion-Jacobson phase, RbSr2Nb3O10, while III is a unique layered
   oxide consisting of charge-neutral La2Ti3O9 anion-deficient perovskite
   sheets stacked one over the other without interlayer cations.
   Interestingly, both II and III convert back to the parent R-P phase in
   a reaction with KNO3. While transformations of the R-P phases to other
   related layered/three-dimensional perovskite oxides in
   ion-exchange/metathesis/dehydration/reduction reactions are known, the
   simultaneous and reversible extraction of both cations and anions in
   the conversions K2La2Ti3O10 reversible arrow KLa2Ti3O9.5 reversible
   arrow La2Ti3O9 is reported here for the first time.


Boulineau, A   Joubert, JM   Cerny, R
Structural characterization of the Ta-rich part of the Ta-Al system
The Ta-rich part of the Ta-Al system has been investigated. On the one
   hand, the accommodation of the non-stoichiometry in the a phase has
   been studied by Rietveld refinement of X-ray powder data obtained from
   different samples on both sides of the ideal composition (Ta2Al,
   P4(2)/mnm, tP30). On the other hand, the structure of the beta phase
   has been determined ab initio from powder synchrotron data (analyzed
   composition Ta50.7Al49.3, refined composition Ta52.6(5)Al47.4(5)
   (Ta45.2(4)Al40.8(4)), stoichiometric composition Ta48Al38, mP86,
   P2(1)/c, a = 9.8707(1) angstrom, b = 9.8766(1) angstrom, c =
   16.3539(2), beta = 116.478(1), R-B = 2.6%). This phase is shown to be
   closely related to the group of the topologically close packed phases.
   In addition, phase relations have been accurately determined in the
   Ta-rich end of the system.


Barrier, N   Malo, S   Hernandez, O   HervieUa, M   Hervieu, M   Raveau, B
The mixed valent tellurate SrTe3O8: Electronic lone pair effect of Te4+
A novel mixed valent tellurium oxide, SrTe3O8, has been synthesized and
   its crystal structure was determined ab initio from powder X-ray
   diffraction data. This oxide, which crystallizes in a tetragonal
   unit-cell, P4(2)/M Space group, with very close a and c cell parameters
   (6.8257(1) and 6.7603(1) angstrom, respectively), exhibits a very
   original structure built up of corner-sharing TeO6 (Te6+) octahedra and
   Te2O8 (Te4+) twin-pyramidal units. The latter ones form
   [Te3O8](infinity) chains running along the [001] and the [110]
   directions. Besides the four sided tunnels where the Sr2+ cations are
   located, there are very large four sided tunnels running along the
   c-axis which are obstructed by the electronic lone pairs of the Te4+


Chong, SY
   Seaton, CC   Kariuki, BM   Tremayne, M
Molecular versus crystal symmetry in tri-substituted triazine, benzene
   and isocyanurate derivatives
The crystal structures of triethyl-1,3,5-triazine- 2,4,6-tricarboxylate
   ( I), triethyl-1,3,5-benzenetricarboxylate ( II) and
   tris-2-hydroxyethyl isocyanurate ( III) have been determined from
   conventional laboratory X-ray powder diffraction data using the
   differential evolution structure solution technique. The determination
   of these structures presented an unexpectedly wide variation in levels
   of difficulty, with only the determination of ( III) being without
   complication. In the case of ( I) structure solution resulted in a
   Rietveld refinement profile that was not ideal, but was subsequently
   rationalized by single-crystal diffraction as resulting from disorder.
   Refinement of structure ( II) showed significant variation in
   side-chain conformation from the initial powder structure solution.
   Further investigation showed that the structure solution optimization
   had indeed been successful, and that preferred orientation had a
   dramatic effect on the structure-solution R-factor search surface.
   Despite the presence of identical side chains in ( I) and ( II), only
   the triazine-based system retains threefold molecular symmetry in the
   crystal structure. The lack of use of the heterocyclic N atom as a
   hydrogen-bond acceptor in this structure results in the formation of a
   similar non-centrosymmetric network to the benzene-based structure, but
   with overall three-dimensional centrosymmetry. The hydrogen-bonded
   layer structure of ( III) is similar to that of other
   isocyanurate-based structures of this type.


Sugimoto, K   Dinnebier, RE   Schlecht, T
Chlorartinite, a volcanic exhalation product also found in industrial
   magnesia screed
The volcanic exhalation product chlorartinite, [Mg-2(CO3)(H2O)(OH)]Cl
    .  H2O, has recently been found to be a minor, and in some
   samples a major, component of magnesia floors for industrial use. In
   order to be able to perform quantitative phase analysis using the
   Rietveld method, its crystal structure was determined from
   high-resolution synchrotron powder diffraction data by the global
   optimization technique of simulated annealing and Rietveld refinement.
   The final R-p and R-wp values are 5.23% and 6.56%, respectively.
   Chlorartinite crystallizes in the rhombohedral space group R3c (No.
   161), with a = 23.14422 (16) angstrom, c = 7.22333 (5) angstrom, V =
   3350.84 (5) angstrom(3), Z = 18. The building units of chlorartinite
   consist of MgO6 octahedra forming 15-membered puckered rings which are
   interconnected by CO3 triangular moieties. The rings are stacked to
   form a honeycomb-like three-dimensional framework structure with large
   isolated channels. Within the channels, free chlorine atoms and
   disordered water molecules are located.


Masciocchi, N   Galli, S   Sironi, A   Cariati, E   Galindo, MA
   Barea, E   Romero, MA   Salas, JM   Navarro, JAR   Santoyo-Gonzalez, F
Tuning the structural and magnetic properties of thermally robust
   coordination polymers
INORGANIC CHEMISTRY 45, 2006, 7612-7620.
Thermally robust materials of the M(5-X-pyrimidin-2-olate) 2 type [M =
   Co, X = Cl (1(Cl)), X = Br (1(Br)), X = I (1(I)); M = Zn, X = Cl
   (2(Cl)), X = Br (2(Br)), X = I (2(I))] have been synthesized. Their
   X-ray powder diffraction structural characterization has revealed that
   they crystallize as vertical bar(4) over bar 2d diamondoid frameworks,
   isomorphous to those of the pristine [M(pyrimidin-2-olate)(2)](n)
   analogues (1H, M = Co; 2(H), M = Zn). The magnetic measurements of the
   1(X) series at magnetic fields of 100, 300, and 5000 Oe reveal a weak
   ferromagnetic ordering taking place below the Neel temperature (T-N
   similar to 20 K), arising from spin canting phenomena of the
   antiferromagnetically coupled cobalt centers. Moreover, magnetic
   hysteresis studies carried out on the 1(X) series at 2 K reveal a
   strong dependence of both the coercive field H-coer (2500, 1000, 775,
   and 500 Oe for 1(Br), 1(Cl), 1(I), and 1(H), respectively) and the
   remnant magnetization M-rem (0.0501 mu(B) for 1(Br) and 1(Cl), 0.0457
   mu(B) for 1(I), and 0.0358 mu(B) for 1(H)) on the 5-substituent of the
   pyrimidin-2-olates. The molecular alloys [Co(5-Y-pyrimidin-2-olate)(2)]
   (Y = Cl/Br, 1(Cl/Br)) and [Co(5-Y'-pyrimidin-2-olate)(2)] (Y' = Br/I,
   1(Br /I)) have also been prepared and characterized, proving that they
   have intermediate properties. These materials combine interesting
   functional properties, such as chemical inertness, magnetism,
   photoluminescence, and (although weak) SHG activity.


Voronin, VI   Ponosov, YS   Berger, IF   Proskurnina, NV   Zubkov, VG
   Tyutyunnik, AP   Bushmelev, SN   Balagurov, AM   Sheptyakov, DV
   Burmakin, EI   Shekhtman, GS   Vovkotrub, EG
Crystal structure of the low-temperature form of K3PO4
INORGANIC MATERIALS 42, 2006, 908-913.
The crystal structure of the low-temperature form of K3PO4 has been
   determined for the first time using neutron diffraction (Rietveld
   method) and Raman spectroscopy: orthorhombic cell (sp. gr. Pnma, Z=4),
   lattice parameters a = 1.12377(2) nm, b = 0.81046(1) nm, c = 0.59227(1)
   nm. The structure is made up of isolated [PO4] tetrahedra, with the
   potassium ions in between.


Colin, JF   Pralong, V   Caignaert, V   Hervieu, M   Raveau, B
A novel layered titanoniobate LiTiNbO5: Topotactic synthesis and
   electrochemistry versus lithium
INORGANIC CHEMISTRY 45, 2006, 7217-7223.
A new layered titanoniobate, LiTiNbO5, an n) 2 member of the
   A(x)M(2n)O(4n+2) family, has been synthesized using a molten salt
   reaction between HTiNbO5 and an eutectic "LiOH/LiNO3". This compound
   crystallizes in the P2(1)/m space group with a) 6.41 angstrom, b) 3.77
   angstrom, c) 8.08 angstrom, and beta = 92 degrees. It exhibits vertical
   bar TiNbO5 vertical bar(infinity) layers similar to HTiNbO5, but
   differs from the latter by a "parallel configuration" of its vertical
   bar TiNbO6 vertical bar(infinity) ribbons between the two successive
   layers. The topotactic character of the reaction suggests that
   exfoliation plays a prominent role in the synthesis of this new form.
   This new phase intercalates reversibly 0.8 lithium through a
   first-order transformation leading to a capacity of 94 mAh/g at a
   potential of 1.67 V vs Li/Li+.


Colin, JF   Bataille, T   Ashbrook, SE   Audebrand, N   Le Polles, L
   Pivan, JY   Le Fur, E
Na-2[(VO)(2)(HPO4)(2)C2O4] .  2H(2)O: Crystal structure
   determination from combined powder diffraction and solid-state NMR
INORGANIC CHEMISTRY 45, 2006, 6034-6040.
The vanadyl oxalatophosphate Na-2[(VO)(2)(HPO4)(2)C2O4] .
   2H(2)O has been synthesized by hydrothermal treatment. Its structure
   has been determined and refined by combining X-ray powder diffraction
   and solid-state NMR techniques. It crystallizes with monoclinic
   symmetry in space group P2(1), a = 6.3534(1) angstrom, b = 17.1614(3)
   angstrom, c = 6.5632(1) angstrom, beta = 106.597(1)degrees. The
   structure is related to that of (NH4)(2)[(VO)(2)(HPO4)(2)C2O4]center
   dot 5H(2)O, which was previously reported. The vanadium phosphate
   framework consists of infinite [(VO)(HPO4)] chains of corner-sharing
   vanadium octahedra and hydrogenophosphate tetrahedra. The oxalate
   groups ensure the connection between the chains to form a 2D structure.
   The sodium ions and the water molecules are located between the anionic
   [(VO)(2)(HPO4)(2)C2O4](2-) layers. The thermal decomposition has been
   studied in situ by temperature-dependent X-ray diffraction and
   thermogravimetry. It takes place in three stages, where the first two
   correspond to water removal and the last to the decomposition of the
   oxalate group and water elimination, leading to the final product


Girgsdies, F
   Dong, WS
   Bartley, JK
   Hutchings, GJ
   Schlogl, R
   Ressler, T
The crystal structure of epsilon-VOPO4
SOLID STATE SCIENCES 8, 2006, 807-812.
The crystal structure of epsilon-VOPO4 was determined in the space
   group Cc from X-ray powder diffraction data using a rigid body
   approach. The resulting structure is compared to a recently published,
   slightly different structure model (space group P2(1)/n) using Rietveld
   refinement. It was found that the new Cc model consistently yields-a
   better fit to the observed data and exhibits a less distorted, more
   stable geometry. The crystal structure of epsilon-VOPO4 is discussed in
   comparison to beta-VOPO4, monoclinic VPO4  .  H2O, and other
   related structures.

2006-73   ???
Karau, F   Schnick, W
A nitridic clathrate: P4N4(NH)(4)(NH3)


Bataille, T   Mahe, N   Le Fur, E   Pivan, JY   Louer, D
Using the parallel tempering algorithm to overcome complex problems in
   structure determination of inorganic materials with laboratory X-rays
ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 1, 2006, 9-14.
The crystal structures of two inorganic compounds,
   Na-2[VO(HPO4)](2)(C2O4) .  2H(2)O and YK(C4O4)(2), have been
   solved ab initio from laboratory X-ray powder diffraction data using
   the parallel tempering algorithm. It is assumed that one reason of the
   failure of the direct methods in structure determination is the
   noticeable diffraction line overlap displayed by the powder patterns.
   Then, we discuss the influence of line broadening on the efficiency of
   the direct methods and the parallel tempering algorithm to solve back
   the crystal structure of,gamma-Zn2P2O7 from powder diffraction patterns
   simulated for several crystallite sizes.


Aitasalo, T   Holsa, J   Laamanen, T   Lastusaari, M
   Lehto, L   Niittykoski, J   Pelle, F
Crystal structure of the monoclinic Ba2MgSi2O7 persistent luminescence
ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 1, 2006, 481-486.
Previously unknown structure of Ba2MgSi2O7 persistent luminescence
   material was observed to be monoclinic with the space group C2/c (No.
   15), Z = 4, a = 8.41275(1), b = 10.71005(1), c = 8.43871(1) angstrom
   and beta = 110.71(1)degrees based on X-ray powder diffraction data. The
   structure is composed of discrete [Si2O7](6-) units connected by
   tetrahedrally coordinated Mg atoms to form sheets in the ac plane.
   Layers of eight-coordinated Ba atoms run parallel to the Mg(Si2O7)
   sheets perpendicular to the unit cell b axis.


Perchiazzi, N
Crystal structure determination and Rietveld refinement of rosasite and
ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 1, 2006, 505-510.
The crystal structure of rosasite, (Cu, Zn)(2)(CO3)(OH)(2), and
   mcguinnessite, (Mg,Cu)(2)(CO3)(OH)(2) have been determined from powder
   data. The two minerals are isostructural, with space group P2(1)/a and
   cell constants a=12.8976(3), b=9.3705(1), c=3.1623(1) angstrom,
   beta=110.262(3)degrees, V =358.54(2) angstrom(3), for rosasite and
   a=12.9181(4), b=9.3923(2), c=3.1622(1) angstrom,
   beta=111.233(3)degrees, V=357.63(2) angstrom(3) for mcguinnessite. The
   crystal structure refinements were lead up to R-p =7.51%, wR(p)=10.39%
   for rosasite and R-p =5.12%, wR(p)=6.22% for mcguinnessite. In both the
   two structures, the Cu coordination octahedron is distorted towards an
   elongated tetragonal bipyramid, whereas the Zn (in rosasite) and Mg (in
   mcguinnessite) coordination octahedra display an almost regular shape,
   their distortion being due to a partial occupancy of Cu. The carbonate
   group was refined as a rigid body, with a regular triangular geometry.
   Metal coordination octahedra polymerize through edge sharing to form
   octahedral "columns" and "ribbons", running along [001] and responsible
   for the acicular habit of these minerals. The structural relationships
   between rosasite and malachite are discussed.


Kavecansky, V   Mihalik, M   Mat'as, S   Mitroova, Z   Lukacova, M
Crystal structure and magnetism of Pr[Fe(CN)(6)] .  4D(2)O
ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 1, 2006, 543-548.
We present an analysis of neutron diffraction patterns taken from the
   powder Pr[Fe(CN)(6)](.)4D(2)O at room temperature and in the
   temperature range from 1.6 to 40 K. Deuterium atoms were localized by
   direct space method based on a Monte Carlo simulation process (Fox) and
   the structure was refined by Rietveld method. Application of detailed
   crystallographic analysis can be very helpful for understanding of
   magnetic behaviour.
   Although the study of magnetic properties of Pr[Fe(CN)(6)](.)4H(2)O by
   NMR spectroscopy, magnetization, DC and AC susceptibility measurements
   has indicated magnetic correlations, at low temperatures, no
   significant difference between low and high temperature powder neutron
   patterns has been detected. Neutron diffraction experiment revealed
   that the compound does not order magnetically down to 1.6 K.


Baies, R   Pralong, V   Caignaert, V   Raveau, B
Soft chemistry synthesis, structure and electrochemical
   characterization of iron phosphates Fe(H2PO4)(3) and Fe(PO3)(3)
The iron phosphate, Fe(H2PO4)(3), was synthesized through a
   precipitation route by means of acidic media. As the compound is highly
   hygroscopic, the structure was solved ab initio by powder X-ray
   diffraction under nitrogen flow at room temperature and 200 degrees C.
   This phase is antiferromagnetic below 30 K. It converts into Fe(PO3)(3)
   at 550 degrees C, after dehydration. Electrochemical characterizations,
   performed on the last compound, show irreversible decomposition into
   metallic iron.


Hofmann, DWM   Kuleshova, LN
A method for automated determination of the crystal structures from
   X-ray powder diffraction data
An algorithm is proposed for determining the crystal structure of
   compounds. In the framework of this algorithm, X-ray powder diffraction
   patterns are compared using a new similarity index. Unlike the indices
   traditionally employed in X-ray powder diffraction analysis, the new
   similarity index can be applied even in the case of overlapping peaks
   and large differences in unit cell parameters. The capabilities of the
   proposed procedure are demonstrated by solving the crystal structures
   of a number of organic pigments (PY111, PR181, Me-PR170).


Cingolani, A   Galli, S   Masciocchi, N   Pandolfo, L
   Pettinari, C   Sironi, A
The competition between acetate and pyrazolate in the formation of
   polynuclear Zn(II) coordination complexes
DALTON TRANSACTIONS iss 20, 2006, 2479-2486.
Hydrated zinc(II) acetate reacts with pyrazole (Hpz) and, depending on
   the reaction conditions, forms different pyrazole-containing species,
   i.e. [{Zn(CH3COO)(mu-pz)(Hpz)}(2)] (1), [{Zn(CH3COO)(2)(Hpz)(2)center
   dot CH3COOH}] (2), [{Zn(mu-pz)(2)}(n)] (3), and
   [{Zn(mu-CH3COO)(mu-pz)}(n)] (4). Their structural models have been
   derived from single-crystal X-ray diffractometry as well as from less
   conventional ab-initio X-ray powder methods. All species contain
   tetrahedrally coordinated Zn(II) ions, with Zn-N and Zn-O bond
   distances close to 2.0 angstrom. The existence of the {Zn(mu-pz)}(2)
   core in the species 1, 3 and 4 indicates the propensity for the
   formation, in the presence of pyrazolate ligands, of well-defined
   dinuclear entities (with Zn  .   .   .  Zn
   contacts in the range 3.6-3.8 angstrom). The latter can mutually
   interact, in the crystals, through either hydrogen-bonding of ancillary
   ligands (as in 1) or coordinative bonds (via acetates, as in 4, or by
   self-complementarity, as in 3). The interconversion paths among these
   species have been studied, employing chemical and thermal methods. In
   particular, the topotactic and quantitative transformation of 1 into 3
   by moderate heating is likely based on a solid-state cooperative
   condensation mechanism of the dangling pyrazolates toward neighbouring
   zinc(II) ions, with concomitant acetic acid extrusion.


Braga, SS   Paz, FAA   Pillinger, M   Seixas, JD
   Romao, CC   Goncalves, IS
Structural studies of beta-cyclodextrin and permethylated
   beta-cyclodextrin inclusion compounds of cyclopentadienyl metal
   carbonyl complexes
[CpM(CO)(n)Cl] complexes with M = Fe (n = 2) and Mo (n = 3) have been
   immobilised in plain beta-cyclodextrin (beta-CD) and permethylated
   beta-CD (TRIMEB) by methods tailored according to the stabilities and
   solubilities of the individual components. Four adducts were obtained
   with a 1: 1 host/guest stoichiometry. The compounds were studied by
   powder X-ray diffraction (XRD), thermogravimetric analysis (TGA),
   C-13{H-1} CP/MAS NMR and FTIR spectroscopy. A comparison of the
   experimental powder XRD data for the TRIMEB/[CpMo(CO)(3)Cl] inclusion
   compound with reference patterns re-vealed that the crystal packing is
   very similar to that reported previously for a TRIMEB/ethyl laurate
   inclusion compound. The unit-cell parameters refined to a = 14.731, b =
   22.476, C = 27.714 angstrom (volume = 9176.3 angstrom(3)), and the
   space group was confirmed as P2(1)2(1)2(1). A hypothetical structural
   model of the inclusion compound was subsequently obtained by global
   optimisation using simulated annealing.


Hansen, MR   Madsen, GKH   Jakobsen, HJ   Skibsted, J
Evaluation of Al-27 and V-51 electric field gradients and the crystal
   structure for aluminum orthovanadate (AlVO4) by density functional
   theory calculations
Three sets of crystal-structure data reported for AIVO(4) from two
   powder-XRD studies and a density functional theory (DFT) investigation,
   employing the Vienna ab initio simulation package (VASP), have been
   examined and refined using the DFT structure-optimization scheme
   implemented in the WIEN2k software. The crystal structures are
   evaluated on the basis of Al-27 and V-51 quadrupole coupling parameters
   recently reported for AIVO4, employing the corresponding electric-field
   gradient (EFG) tensor elements obtained from the DFT calculations. The
   DFT calculations provide a reliable assignment of the Al-27/V-51
   resonances from three distinct Al and three V environments to the
   specific crystallographic sites in the asymmetric unit for AIVO4. An
   improved agreement between experimental quadrupole tensor elements and
   calculated EFG tensors is achieved after the DFT structure
   optimizations and consistent results are obtained using the three
   different structures as starting points. The improvement of the
   structural data is also supported by an evaluation of the Al-O and V-O
   bond lengths before and after DFT structure optimization. The V-51
   nuclear quadrupole moment, vertical bar Q(V-51)vertical bar = 4.8 +/-
   0.1 fm(2), derived from the present analysis, represents a value of
   higher accuracy than earlier reported Q(V-51) values. The origin of the
   Al-27 and V-51 EFGs are investigated by an evaluation of the
   orientations of the EFG tensors in the crystal frame and by an
   examination of the individual contributions from the valence electrons
   and the surrounding lattice. The latter investigation shows that the
   magnitude and orientation of the tensors are largely determined by the
   p-p(Al-27) and p-p, d-d(V-51) orbital contributions to the valence
   electrons, while the lattice part only gives a minor contribution for
   both nuclei.


Schmidt, MU   Hofmann, DWM   Buchsbaum, C   Metz, HJ
Crystal structures of pigment Red 170 and derivatives, as determined by
   X-ray powder diffraction

2006-84  ???

Cheung, EY   Harris, KDM   Kang, T   Scheffer, JR   Trotter, J
Structure-reactivity correlations for solid-state enantioselective
   photochemical reactions established directly from powder X-ray


Sorby, MH   Gunnaes, AE   Lovvik, OM   Brinks, HW   Fjellvag, H   Hauback, BC
The crystal structure of Zr2NiD4.5
The crystal structure of Zr2NiD4.5 has been determined by a combination
   of synchrotron radiation powder X-ray diffraction, electron diffraction
   and powder neutron diffraction data. Deuterium ordering results in a
   triclinic supercell given by a(super) = 6.81560 (7), b(super) = 8.85137
   (9), c(super) = 8.88007 (10) A, alpha(super) = 79.8337 (8), beta(super)
   = 90.0987 (9), gamma(super) = 90.3634 (9)degrees, which relates to the
   non-super unit cell as a(super) = -a, b(super) = -b-c, c(super) = -b+c.
   The centrosymmetric and fully ordered deuterium sublattice was
   determined by simulated annealing and Rietveld refinement. Deuterium
   was found to occupy three types of tetrahedral sites: two that are
   coordinated by four Zr atoms and one that is coordinated by three Zr
   atoms and one Ni atom. All D-D distances are longer than 2 A. The
   feasibility of the crystal structure was supported by density
   functional theory calculations.


Gramm, F   Baerlocher, C   McCusker, LB   Warrender, SJ   Wright, PA
   Han, B   Hong, SB   Liu, Z   Ohsuna, T   Terasaki, O
Complex zeolite structure solved by combining powder diffraction and
   electron microscopy
NATURE 444, 2006, 79-81.
Many industrially important materials, ranging from ceramics to
   catalysts to pharmaceuticals, are polycrystalline and cannot be grown
   as single crystals. This means that non-conventional methods of
   structure analysis must be applied to obtain the structural information
   that is fundamental to the understanding of the properties of these
   materials. Electron microscopy might appear to be a natural approach,
   but only relatively simple structures have been solved by this route.
   Powder diffraction is another obvious option, but the overlap of
   reflections with similar diffraction angles causes an ambiguity in the
   relative intensities of those reflections. Various ways of overcoming
   or circumventing this problem have been developed(1,2), and several of
   these involve incorporating chemical information into the structure
   determination process(3-7). For complex zeolite structures, the FOCUS
   algorithm(8,9) has proved to be effective. Because it operates in both
   real and reciprocal space, phase information obtained from
   high-resolution transmission electron microscopy images can be
   incorporated directly into this algorithm in a simple way. Here we show
   that by doing so, the complexity limit can be extended much further.
   The power of this approach has been demonstrated with the solution of
   the structure of the zeolite TNU-9 (\H-9.3\[ Al9.3Si182.7O384]; ref.
   10) with 24 topologically distinct ( Si, Al) atoms and 52 such O atoms.
   For comparison, ITQ-22 ( ref. 11), the most complex zeolite known to
   date, has 16 topologically distinct (Si, Ge) atoms.


Lufaso, MW   Macquart, RB   Lee, Y   Vogt, T   zur Loye, HC
Structural studies of Sr2GaSbO6, Sr2NiMoO6, and Sr2FeNbO6 using
   pressure and temperature
Results from high-pressure synchrotron x-ray diffraction and
   high-temperature x-ray diffraction measurements on polycrystalline
   samples of the tetragonal perovskites Sr2GaSbO6, Sr2NiMoO6, and
   Sr2FeNbO6 are reported. A phase transition, where the unit cell changes
   symmetry from tetragonal to cubic, is observed for each compound at
   elevated temperatures. The phase transition changes the structure from
   one exhibiting an octahedral tilting distortion at ambient temperature
   to one that is untilted above the transition temperature. At elevated
   pressures the c/v root 2a lattice parameter ratio increases, indicating
   that the magnitude of the octahedral tilting distortion is increasing
   as a function of pressure. In the pressure range studied, up to similar
   to 6 GPa, no phase transitions were observed.


Fernandez-Bertran, JF   Hernandez, MP   Reguera, E   Yee-Madeira, H
   Rodriguez, J   Paneque, A   Llopiz, JC
Characterization of mechanochemically synthesized imidazolates of Ag+1,
   Zn+2, Cd+2, and Hg+2 : Solid state reactivity of nd(10) cations
Silver, zinc, cadmium, and mercury imidazolates have been synthesized
   mechanochemically by milling imidazole and the metal oxides in an agate
   mortar. The reaction products were characterized by FTIR and XRPD
   techniques. The results obtained for the mechanochemical imidazolates
   have been compared with those obtained by precipitation reported in the
   literature. The mechanochemical Ag imidazolate has the same
   orthorhombic crystal structure as the precipitated one. The
   mechanochemical Zn imidazolate has a tetragonal structure with similar
   crystal parameters to those of Zn(Imz)(2)H2O, but no water molecules
   are present in the structure. This new anhydrous form is a polymorph of
   the one obtained by precipitation. The mechanochemical Cd imidazolate
   has a monoclinic structure which is the polymorph of the precipited
   orthorombic form. The mechanochemical Hg imidazolate presents a
   hexagonal structure which is a polymorph of the orthorombic structure
   obtained by precipitation. The influence of the nd(10) electronic
   configuration of the cations on the mechanochemical reaction is


Pandian, RP   Kim, YI   Woodward, PM   Zweier, JL   Manoharan, PT   Kuppusamy, P
The open molecular framework of paramagnetic lithium
   octabutoxynaphthalocyanine: implications for the detection of oxygen
   and nitric oxide using EPR spectroscopy
The oxygen-induced broadening of the electron paramagnetic resonance
   (EPR) spectrum of lithium octa-n-butoxy-naphthalocyanine (LiNc-BuO) is
   interpreted in terms of its open molecular framework crystal structure.
   LiNc-BuO was prepared as a microcrystalline powder and its structure
   analyzed using X-ray powder diffraction techniques. The structure
   contains strongly coupled dimers of LiNc-BuO molecules, which favors a
   high degree of spin exchange, and results in a single sharp EPR line.
   The molecular packing leads to a structure with open channels large
   enough (10 x 6 angstrom(2)) for the penetration of small diatomic
   paramagnetic molecules such as oxygen (O-2) and nitric oxide (NO), as
   well as the larger triatomic species, nitrogen dioxide (NO2). The EPR
   linewidth of LiNc-BuO is extremely sensitive to the concentration of
   paramagnetic gases in the pressure range of 0 - 760 mmHg. The effect of
   oxygen on LiNc-BuO is reversible without any signs of permanent
   adsorption or chemical oxidation. The time response of the effect of
   oxygen is extremely rapid (0.24 s). The paramagnetic gas-sensing
   properties of LiNc-BuO are attributed to the open molecular framework
   of the crystal structure. The oxygen-sensing property, combined with
   the previously established biostability and biocompatibility of this
   material, should enable precise and accurate measurements of oxygen
   concentration in biological systems using EPR spectroscopy.

Asthalter, T   Sergueev, I   van Burck, U   Dinnebier, R
Identification of a rotator phase of octamethyl ferrocene and
   correlations between its structural and dynamical properties
The low- and high-temperature phases of octamethyl ferrocene were
   studied in detail, using high-resolution X-ray powder diffraction,
   differential scanning calorimetry and nuclear resonant scattering, in
   particular the novel technique of synchrotron radiation perturbed
   angular correlations (SRPAC). Much as in the case of an analogous but
   more unsymmetrical molecule, octamethyl ethinyl ferrocene, the
   high-temperature phase possesses the space group R3m with lattice
   parameters a = b = 12.5568(1) angstrom, c = 9.6045(1) angstrom, which
   in the rhombohedral setting correspond to a = 7.9251(1) angstrom, alpha
   = 104.79 degrees. An increase of the volume per formula unit of about
   12% across the phase transition is observed.
   The rotation of the electric field gradient, which can be identified
   with the rotation of the entire molecule within the lattice, follows
   Arrhenius behaviour with a high activation energy of (40.3 +/- 3.3) kJ
   mol(-1). Whereas precursor effects and a change in activation energy
   were observed for octamethyl ethinyl ferrocene, no such effects are
   observed for octamethyl ferrocene. We relate this difference to the
   absence of the ethinyl substituent in octamethyl ferrocene.

2006-91   ???

Li, RK    Yu, Y
Ba4Ga2B8O18Cl2, NaCl: A new polar structure with NaCl inclusion
INORGANIC CHEMISTRY 45, 2006, 6840-6843.
The title compound, Ba4Ga2B8O18Cl2, NaCl, is found to crystallize in a
   polar space group P4(2)nm with cell dimensions of a = 12.1134(2)
   angstrom and c = 6.8456(1) angstrom. The basic building blocks of the
   structure are the B4O9 groups, which are interconnected by the GaO4
   tetrahedron to form a three-dimensional net with Ba-2(+) ion-, Cl-
   ion-, and NaCl molecule-filled tunnels. This net structure is closely
   related to that of mineral hilgardite, with which many variant
   compounds have been found. Both a powder second-harmonic-generation
   test and calculations suggest that it possesses an optical nonlinearity
   comparable to that of potassium dihydrogen phosphate.


Dorset, DL   Kennedy, GJ   Strohmaier, KG   Diaz-Cabanas, MJ   Rey, F   Corma, A
P-derived organic cations as structure-directing agents: Synthesis of a
   high-silica zeolite (ITQ-27) with a two-dimensional 12-ring channel
Recently, efforts have been made to synthesize large-pore,
   multidimensional zeolite frameworks as a basis for new catalysts to
   improve various hydrocarbon conversions. A new aluminosilicate zeolite,
   ITQ-27, has been prepared using the phosphorus-containing
   structure-directing agent, dimethyldiphenylphosphonium. Its crystal
   structure was determined in its calcined form by direct methods (
   FOCUS) on synchrotron powder diffraction data (lambda = 0.8702
   angstrom) after the unit cell and space group were determined from tilt
   electron diffraction experiments on individual microcrystals. The
   material crystallizes in space group Fmmm, where a = 27.7508(5)
   angstrom, b = 25.2969(7) angstrom, and c = 13.7923(4) angstrom. The
   final model, refined by Rietveld methods, comprises seven unique
   T-sites forming a framework with straight 12-MR channels that are
   connected by 14-MR openings between them. ( Corresponding 12-ring pore
   dimension is 6.94 angstrom x 6.20 angstrom.) Since access from one
   14-MR opening to the next is through the 12-MR channel, the structure
   is best described as a two-dimensional, 12-MR framework.

Ben Yahia, H   Gaudin, E   Darriet, J   Dai, D   Whangbo, MH
Comparison of the crystal structures and magnetic properties of the
   low- and high-temperature forms of AgCuPO4: Crystal structure
   determination, magnetic susceptibility measurements, and spin dimer
INORGANIC CHEMISTRY 45, 2006, 5501-5509.
The crystal structure of the low-temperature form of AgCuPO4 (i.e.,
   alpha-AgCuPO4) was determined by powder X-ray diffraction and was
   compared with that of the high-temperature form of AgCuPO4 (i.e.
   beta-AgCuPO4). The magnetic properties of the two forms were examined
   by measuring their magnetic susceptibilities and evaluating the
   relative strengths of their spin-exchange interactions on the basis of
   spin-dimer analysis. Both forms of AgCuPO4 have layers of Cu2P2O8
   alternating with silver-atom double layers; beta-AgCuPO4 has two
   Cu2P2O8 layers per unit cell, while alpha-AgCuPO4 has one. The
   coordinate environment of each Cu2+ ion is close to being a distorted
   square pyramid in alpha-AgCuPO4, but it is close to being a distorted
   trigonal bipyramid in beta-AgCuPO4. The magnetic susceptibilities of
   alpha- and beta-AgCuPO4 are well simulated by an antiferromagnetic
   alternating-chain model, which leads to J/K-B = -146.1 K and alpha
   J/K-B = -75.8 K for alpha-AgCuPO4, and J/K-B = -82.6 K and alpha J/K-B
   = -31.7 K for beta-AgCuPO4 (with the convention in which the
   spin-exchange parameter between two adjacent spin sites is written as
   2J). The spin gaps, Delta/K-B, obtained from these parameters are 93.7
   K for alpha-AgCuPO4 and 62.3 K for beta-AgCuPO4. The strongest spin
   exchange in both forms of AgCuPO4 comes from a super-superexchange
   path, and this interaction is stronger for R-AgCuPO4 than for
   beta-AgCuPO4 by a factor of similar to 2, in good agreement with the
   experiment. Our analysis supports the use of this model for
   beta-AgCuPO4 and indicates that the spin lattice of alpha-AgCuPO4 would
   be better described by a two-dimensional net made up of weakly
   interacting alternating chains.


Kirik, SD   Starkov, AK   Kozhuhovskay, GA
cis-Amminedichloroisopropylamine-platinum(II) by X-ray powder
   diffraction analysis
The title compound, [PtCl2(C3H9N)(NH3)], was obtained from potassium
   tetrachloroplatinate(II) by a two-step route. Ab initio crystal
   structure determination was carried out using X-ray powder diffraction
   techniques. Patterson and Fourier syntheses were used for the atom
   locations and the Rietveld technique for the final structure
   refinement. The Pt coordination is close to planar, with Cl atoms in a
   cis orientation. Molecules are combined into groups of two molecules,
   with antiparallel PtN2Cl2 planes and a shortest Pt  .  center
   dot  .  Pt distance of 3.42 angstrom. The molecule groups are
   packed in a parquet motif into corrugated layers parallel to ab. The
   molecules in the layers are linked by H-N  .   .  center
   dot Cl hydrogen bonds.


Derollez, P   Hedoux, A   Guinet, Y   Lefebvre, J   Descamps, M   Hernandez, O
Micro(nano)structure of the glacial state in triphenyl phosphite (TPP)
ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 2, 2006, 557-562.
The structure and microstructure of the glacial state in triphenyl
   phosphite (TPP, P(OC6H5)(3)) transformed at 222 K have been determined
   from powder synchrotron X-ray diffraction data through Rietveld and Le
   Bail refinements. It is shown that the glacial state is composed of
   crystallites of the stable crystal phase coexisting with
   non-transformed supercooled liquid. The apparent size of the
   crystallites - depending on the ageing temperature at which the glacial
   state is isothermally formed - is found to be equal to 329.2(2)
   angstrom at 222 K. A simulated diffraction pattern shows that at
   temperatures lower than 220 K, the more amorphous-like shape is due to
   the coexistence of non-transformed supercooled liquid and to a size
   effect of the crystallites of the stable phase.


Ramirez-Cardona, M   Escamilla-Casas, JC   Cuevas-Diarte, MA   Barajas-Rosales, I
Structure determination of 1-pentanol (C5H12O)at 183 K
ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl 23 part 2, 2006, 601-606.
Powder X-ray diffraction pattern of the crystalline phase of I-pentanol
   was recorded with a sensitive curved detector (CPS120) at 183 K. The
   structure has been solved with the Patterson Search [1] method. The
   resulting structure was refined by rigid-body Rietveld analysis. The
   cell is monoclinic, space group P2(1)/c, Z = 4 and with the following
   parameters: a = 15.592(g) angstrom, b = 4.349(1) angstrom, c = 9.157(1)
   angstrom, beta = 104.7(7)degrees, V = 600.6(3) angstrom(3). The
   structure contains one molecule in the asymmetric unit with the O-H
   bond in gauche conformation with respect to the alkyl skeleton. Packing
   is defined by OH... OH hydrogen bonds that link the I-pentanol
   molecules along the b axis as zigzag chains.


Pan, ZG   Xu, MC   Cheung, EY   Harris, KDM   Constable, EC   Housecroft, CE
Understanding the structural properties of a dendrimeric material
   directly from powder X-ray diffraction data
JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 11620-11623.
Complete structure determination of an early-generation dendrimeric
   material has been carried out directly from powder X-ray diffraction
   data, using the direct-space genetic algorithm technique for structure
   solution followed by Rietveld refinement. This work represents the
   first application of modern direct-space techniques for structure
   determination from powder X-ray diffraction data in the case of a
   dendrimeric material and paves the way for the future application of
   this approach to enable complete structure determination of other
   dendrimeric materials that cannot be prepared as single crystal samples
   suitable for single crystal X-ray diffraction studies.


Dinnebier, R   Sofina, N   Hildebrandt, L   Jansen, M
Crystal structures of the trifluoromethyl sulfonates M(SO3CF3)(2) (M =
   Mg, Ca, Ba, Zn, Cu) from synchrotron X-ray powder diffraction data
The crystal structures of divalent metal salts of trifluoromethyl
   sulfonic acid ('trifluoromethyl sulfonates') M( SO3CF3)(2) (M = Mg, Ca,
   Ba, Zn, Cu) were determined from high-resolution X-ray powder
   diffraction data. Magnesium, calcium and zinc trifluoromethyl sulfonate
   crystallize in the rhombohedral space group R (3) over bar . Barium
   trifluoromethyl sulfonate crystallizes in the monoclinic space group
   I2= a(C2/c) and copper trifluoromethyl sulfonate crystallizes in the
   triclinic group P (1) over bar. Within the crystal structures the
   trifluoromethyl sulfonate anions are arranged in double layers with the
   apolar CF3 groups pointing towards each other. The cations are located
   next to the SO3 groups. The symmetry relations between the different
   crystal structures have been analysed.

Hildebrandt, L   Dinnebier, R   Jansen, M
Crystal structure and ionic conductivity of three polymorphic phases of
   rubidium trifluoromethyl sulfonate, RbSO3CF3
INORGANIC CHEMISTRY 45, 2006, 3217-3223.
The crystal structures of three polymorphic phases of rubidium
   trifluoromethyl sulfonate (RbSO3CF3, rubidium 'triflate') were solved
   from X-ray powder diffraction data. At room temperature, rubidium
   triflate crystallizes in the monoclinic space group Cm with lattice
   parameters of a = 19.9611(5) angstrom, b = 23.49113(7) angstrom, c =
   5.1514(2) angstrom, beta = 102.758(2)degrees; Z = 16. At T = 321 K, a
   first-order phase transition occurs toward a monoclinic phase in space
   group P2(1) with lattice parameters at T = 344 K of a = 10,3434(5)
   angstrom, b = 5.8283(3) angstrom, c = 5.1982(3) angstrom, beta =
   104.278(6)degrees; Z = 2). At T = 461 K, another phase transition, this
   time of second order, occurs toward an orthorhombic phase in space
   group Cmcm with lattice parameters at T = 510 K of a = 5.3069(2)
   angstrom, b = 20.2423(10) angstrom, c = 5.9479(2) angstrom; Z = 4. As a
   common feature within all three crystal structures of rubidium
   triflate, the triflate anions are arranged in double layers with the
   lipophilic CF3 groups facing each other. The rubidium ions are located
   between the SO3 groups. The general packing is similar to the packing
   in cesium triflate. Rubidium triflate can be classified as a solid
   electrolyte with a specific ionic conductivity of sigma = 9.89 x 10(-9)
   S/cm at T = 384 K and sigma = 3.84 x 10(-6) S/cm at T = 481 K.


Leineweber, A   Nitsche, H
La5Al3Ni2 - an intermetallic phase observed upon crystallization of
   La50Al25Ni25 metallic glass
The yet unknown intermetallic phase La5Al3Ni2 was obtained by partially
   crystallizing amorphous La50Al25N25 at 550 K (further heating above 600
   K leads to irreversible disappearance of this phase), and its crystal
   structure was determined from X-ray powder diffraction data. The
   crystal structure of the La5Al3Ni2 phase constitutes a new structure
   type (C-mcm, a = 14.231 angstrom, b = 6.914 angstrom, c = 10.460
   angstrom, oC40) and is built from [Al3Ni2] chains surrounded by La
   atoms. In the ternary system La-Al-Ni La5Al3Ni, is located on the
   section La50Al50-nNin (0 <= n <= 50) with the binary compounds LaAl and
   LaNi as end members. Strikingly, also the crystal structures of the end
   members can be conceived as chain structures with Al and Ni chains
   surrounded by La, respectively.


Funke, K   Banhatti, RD   Wilmer, D   Dinnebier, R   Fitch, A   Jansen, M
Low-temperature phases of rubidium silver iodide: Crystal structures
   and dynamics of the mobile silver ions
Recently, broad-band conductivity spectra have been taken in the
   low-temperature gamma-phase of the archetypal fast ion conductor
   RbAg4I5. Attempts to reproduce the experimental data in a simple model
   calculation have led to the conclusion that strictly localized
   displacive movements of interacting ionic charge carriers should play
   an important role in the low-temperature phase. However, with no
   detailed structural study of gamma-RbAg4I5 available, the relevant
   processes could not be identified within the crystal structure. This
   state of affairs has triggered the present investigation of the
   structures of all three phases of rubidium silver iodide. Powder
   diffraction data of RbAg4I5 have been collected at the high-resolution
   powder diffractometer at ID31 at the European Synchrotron Radiation
   Facility (ESRF). The structure of the gamma-phase has been solved by
   successive Rietveld refinements in combination with difference Fourier
   analyses. The same structural principle is found to prevail in all
   three phases, interconnected distorted RbI6 octahedra forming a
   three-dimensional framework, which undergoes only displacive structural
   changes during the alpha - beta and beta - gamma phase transitions.
   With decreasing temperature, the disorder in the silver sublattice is
   found to decrease, and a clustering of the disordered silver ions is
   found to develop. In the gamma-phase, "pockets" containing partially
   occupied silver sites have been identified, and it is suggested that
   the localized displacive motion detected by conductivity spectroscopy
   is performed by the silver ions located within these pockets.


Yang, XB
Synthesis and crystal structure of tetramethylammonium fluoride
Octadecasil, a clathrate-type inclusion compound, has been synthesized
   hydrothermally at 453 K with a gel having the composition
   1.0SiO(2):0.53tetramethylammonium (TMA(+)):0.54fluoride:86H(2)O. The
   crystal structure has been determined based on powder X-ray diffraction
   data taken at 298 K, and has been refined using Rietveld method. The
   result confirms the AST-type, all-silica framework model developed by
   Caullet et al. [P. Caullet, J.L. Guth, J. Hazm, J.M. Lamblin, H. Gies,
   Eur. J. Solid State Inorg. Chem. 28 (1991) 345]. Furthermore, by using
   a rigid body model the position and orientation of the occluded TMA(+)
   cation in the rhombododecahedral [4(6)6(12)] cage can be determined; F-
   anion has been located in the hexahedral [4(6)] cage. The unit cell
   parameters, in the tetragonal space group I4/m, have been refined as: a
   = b = 9.07 angstrom, c = 13.44 angstrom, cell volume = 1104.97
   angstrom(3). The refined unit cell composition is
   \[N(CH3)(4)(+)](2.0)F-1.9(-)\[Si20O40], i.e., both TMA(+) and F- ions
   possess near full occupancies, and compensate each other's electronic
   charges. The crystallization of the AST framework structure is the
   result of a cooperative structure-directing effect of both ions.


Guguta, C   Meekes, H   de Gelder, R
Crystal structure of aspartame anhydrate from powder diffraction data.
   Structural aspects of the dehydration process of aspartame
CRYSTAL GROWTH & DESIGN 6, 2006, 2686-2692.
Aspartame has three pseudo-polymorphic forms, two hydrates and a
   hemi-hydrate, for which crystal structures were determined from
   single-crystal diffraction data. This paper presents the crystal
   structure of the anhydrate, which was obtained by dehydrating the
   hemi-hydrate. The crystal structure of aspartame anhydrate,
   L-aspartyl-L-phenylalanine methyl ester, was determined from X-ray
   powder diffraction data. Aspartame anhydrate crystallizes in the
   monoclinic system with space group P2(1) and cell parameters: a =
   19.4078( 10) angstrom, b = 4.9605(2) angstrom, c = 15.6547(9) angstrom,
   beta = 94.876( 2), V = 1501.65(14) angstrom(3). Final Rietveld
   refinement resulted in R-wp = 2.26 and a GOOF of 2.30. Comparing the
   hydrates of aspartame and using molecular modeling provide a complete
   and clear picture of the dehydration behavior of aspartame at the
   molecular level.


Fukuda, K   Wata, T   Niwa, T
Crystal structure and phase transformations of calcium yttrium
   orthophosphate, Ca3Y(PO4)(3)
Crystal structure and phase transformations of calcium yttrium
   orthophosphate Ca3Y(PO4)(3) were investigated by X-ray powder
   diffraction, selected-area electron diffraction, transmission electron
   microscopy and optical microscopy. The high-temperature phase is
   isostructural with eulytite, cubic (space group I (4) over bar 3d) with
   a = 0.983320(5) nm, V = 0.950790(8) nm(3), Z = 4 and D-x = 3.45 Mg
   m(-3). The crystal structure was refined with a split-atom model, in
   which the oxygen atoms are distributed over two partially occupied
   sites. Below the stable temperature range of eulytite, the crystal
   underwent a martensitic transformation, which is accompanied by the
   formation of platelike surface reliefs. The inverted crystal is
   triclinic (space group P1) with a = 1.5726(1) nm, b = 0.84267(9) nm, c
   = 0.81244(8) nm, alpha = 109.739(4)degrees, beta = 90.119(5)degrees,
   gamma = 89.908(7)degrees, V = 1.0134(1) nm(3), Z = 4 and D-x = 3.24 Mg
   m(-3). The crystal grains were composed of pseudo-merohedral twins. The
   adjacent twin domains were related by the pseudo-symmetry mirror planes
   parallel to {10 (1) over bar} with the composition surface {10 (1) over
   bar}. When the eulytite was cooled relatively slowly from the stable
   temperature range, the decomposition reaction of
   Ca(3)y(PO4)(3)->beta-Ca-3(PO4)(2)+YPO4 occurred.


Stephenson, GA   Liang, C
Structural determination of the stable and meta-stable forms of
   atomoxetine HCl using single crystal and powder X-ray diffraction
Strattera (TM) is the first FDA-approved nonstimulant medication for
   the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in
   children, adolescents, and adults. Two polymorphic forms and an
   amorphous form of the active pharmaceutical ingredient, atomoxetine
   HCl, were discovered during drug development. The thermodynamically
   stable polymorphic form was selected for the commercial product. The
   stable form readily grows as crystals suitable for single crystal
   diffraction. The meta-stable crystal form is isolated by rapid
   crystallization, providing crystals that are too small for routine
   single crystal methods; consequently its structure was determined by
   X-ray powder diffraction.


Stinton, GW   Hampson, MR   Evans, JSO
The 136-atom structure of ZrP2O7 and HfP2O7 from powder diffraction data
INORGANIC CHEMISTRY 45, 2006, 4352-4358.
There has been considerable debate in the literature about the true
   room-temperature structure of ZrP2O7 and related materials. In this
   article we describe how a combination of information from solid-state
   P-31 NMR and powder diffraction data can be used to determine the
   structure of this 136 unique-atom material. The structure has been
   solved using a combination of simulated annealing and Rietveld
   refinement performed simultaneously on X-ray and neutron diffraction
   data. Despite the close to cubic metric symmetry of the material, we
   show how its true orthorhombic structure ( space group Pbca) can be
   refined to a high degree of precision.


Rajeswaran, M   Blanton, TN   Giesen, DJ   Whitcomb, DR   Zumbulyadis, N
   Antalek, BJ   Neumann, MM   Misture, ST
Azine bridged silver coordination polymers: Powder X-ray diffraction
   route to crystal structure determination of silver benzotriazole
In continuation of our interest in solid-state Structures of silver
   complexes of photographic importance, the structure for silver
   benzotriazole (AgBZT), has now been obtained. The preferred method for
   solving crystal structures is via single-crystal X-ray diffraction
   (XRD). However, for some materials, growing single crystals of
   appropriate size and quality is often difficult or even impossible.
   AgBZT is an example of such a silver complex with poor solubility. The
   usual routes to preparing single crystals using recrystallization from
   a cooperating solvent resulted in polycrystalline powder samples. We
   propose a crystal Structure for AgBZT, solved from synchrotron X-ray
   powder diffraction data, using a direct-space Monte Carlo simulated
   annealing approach. AgBZT crystals are monoclinic, (P2(1)/c), with unit
   cell dimensions, a = 14.8052(3) angstrom, b = 3.7498(4) angstrom, c =
   12.3495(12) angstrom. and beta = 114.200(6)degrees. The AgBZT complex
   is constructed from all three of the Benzotriazole (BZT) nitrogens
   bonding to a separate silver atom. As a consequence of this bonding
   mode, the Structure is a highly cross-linked, coordination polymer.


Wallez, G   Souron, JP   Quarton, M
Crystal structure and thermal evolution of inedite alpha-Zr2O(PO4)(2)
   and alpha-Hf2O(PO4)(2)
SOLID STATE SCIENCES 8, 2006, 1061-1066.
The structures of isotypic alpha-Zr2O(PO4)(2) (S.G. I2/m, a =
   10.2726(6), b = 6.5957(3), c 10.0665(5) angstrom, beta =
   95.433(3)degrees, V = 679.00(6) angstrom(3), Z = 4) and
   alpha-Hf2O(PO4)(2) (S.G. I2/m, a = 10.2301(3), b 6.5819(2), c =
   10.0075(5) angstrom, 95.371(1)degrees,. V = 670.87(3) angstrom(3), Z =
   4) have been resolved ab initio by Rietveld analysis. At variance with
   the beta-form, they show both MO6 and MO7 polyhedra (M = Zr, Hf),
   forming ribbons with the PO4 tetrahedra. A lattice energy calculation
   explains why the alpha-form is less stable than the beta-form, thus
   making the alpha-beta transition irreversible. However, the
   substitution of smaller Hf-IV for Zr-IV allows to keep the a-framework
   up to 1500 degrees C by stabilizing the MO6 octahedra.


Karray, R   Kabadou, A   Ben Salah, A   van der Lee, A
X-ray powder diffraction study of cesium ammonium hexachlorotellurate
POWDER DIFFRACTION 21, 2006, 225-228.
The crystal structure of cesium ammonium hexachlorotellurate
   [Cs-0.86(NH4)(0.14)](2)TeCl6, has been determined using X-ray powder
   diffraction techniques. At room temperature, the title compound
   crystallizes in the cubic space group Fm (3) over barm, with a lattice
   parameter a = 10.470(17) angstrom. The Rietveld refinement of the
   structure led to final confidence factors R-p=0.0338 and R-wp=0.0487.
   The structure of [Cs-0.86(NH4)(0.14)](2)TeCl6 belongs to the large
   family of K2PtCl6-related structures. The H atoms of the ammonium group
   are orientated with its apex toward Te atoms as seen in the related
   compound (NH4)(2)SiF6. An IR spectroscopic study was performed to
   confirm the results of the diffraction method, notably concerning the
   presence of the ammonium group.


de Armas, HN   Peeters, OM   Blaton, N   van den Mooter, G
   de Ridder, DJA   Schenk, H
Crystal structure of carnidazole form II from synchrotron X-ray powder
   diffraction: Structural comparison with form I, the hydrated form and
   the low energy conformations in vacuo
The crystal structure of carnidazole form II, O-methyl
   [2-(2-methyl-5-nitro1H-imidazole-1-yl)ethyl]thiocarbamate, has been
   determined using synchrotron X-ray powder diffraction in combination
   with simulated annealing and whole profile pattern matching, and
   refined by the Rietveld method. For structure solution, 12 degrees of
   freedom were defined: one motion group and six torsions. Form II
   crystallizes in space group P2(1)/n, Z = 4, with unit cell parameters
   after Rietveld refinement: a = 13.915(4), b=8.095(2), c=10.649(3)
   angstrom, beta=110.83(1)degrees, and V=1121.1(5)angstrom(3). The two
   polymorphic forms, as well as the hydrate, crystallize in the
   monoclinic space group P21/n having four molecules in the cell. In form
   II, the molecules are held together by forming two infinite zig-zag
   chains via hydrogen bonds of the type N-H...N, the same pattern as in
   form I. A conformational study of carnidazole, at semiempirical PM3
   level, was performed using stochastic approaches based on modification
   of the flexible torsion angles. The values of the torsion angles for
   the molecules of the two polymorphic forms and the hydrate of
   carnidazole are compared to those obtained from the conformational
   search. Form I and form II are enantiotropic polymorphic pairs this
   agrees with the fact that the two forms are conformational polymorphs.

2006-111  ???

Hirano, S   Toyota, S   Toda, F   Fujii, K   Uekuasa, H
Solid-state phase transition of an inclusion complex of
   5-methyl-2-pyridone with 1,3,5-benzenetricarboxylic acid


Mahe, N   Audebrand, N
Structure and thermal behaviour of ScK(C2O4)(2)(H2O)(2) and
   InRb1-x(H3O)(x)(C2O4)(2)(H2O)(2) .  0.5(H2O): Two members of a
   family of open-framework oxalates with isotypic helical structures and
   zeolite-like properties
SOLID STATE SCIENCES 8, 2006, 988-999.
Two new mixed oxalates with an open architecture, ScK(C2O4)(2)(H2O)(2)
   (I) and InRb0.77(H3O)(0.23)(C2O4)(2)(H2O)(2).0.5(H2O) (II), have been
   synthesised from precipitation methods at ambient temperature. They
   crystallize in hexagonal system, space group P6(2)22 (No. 180), Z = 3,
   with the following unit-cell parameters for I: a = 8.8667(2) angstrom,
   c = 11.4908(4) angstrom, V = 782.36(4) angstrom(3), for II: a =
   9.0148(3) angstrom, c = 11.4645(3) angstrom, V = 806.86(4) angstrom(3).
   The two structures belong to a family of isotypic helical anionic
   open-frameworks built from square antiprismatic coordinated metals and
   bischelating oxalates. The counter-cations K+ and Rb+/H3O+ are located
   in the tunnels of the framework. The thermal decomposition process has
   demonstrated zeolite-like properties associated with weakly-bonded
   water molecules located in the voids of the framework.

Sassoye, C   de Kozak, A
Crystal structure and thermal behaviour of K-2[CrF5  .  H2O]
 K-2[CrF(5) .  H2O] is monoclinic: a = 9.6835(3) angstrom, b =
   7.7359(2) angstrom, c = 7.9564(3) angstrom, beta = 95.94(1)degrees, Z =
   4, space group C2/c (n degrees 15). Its crystal structure was solved
   from its X-ray powder pattern recorded on a powder diffractometer,
   using for the refinement the Rietveld method. It is built up from
   isolated octahedral [CrF(5) .  OH2](2-) anions separated by
   potassium cations. The dehydration of K-2[CrF(5) .  H2O] leads
   to anhydrous orthorhombic K2CrF5: a = 7.334(2) angstrom, b = 12.804(4)
   angstrom, c = 20.151(5) angstrom, Z = 16, space group Pbcn (n degrees
   60), isostructural with K2FeF5.


Marichal, C   Chezeau, JM   Roux, M   Patarin, J   Jorda, JL
   McCusker, LB   Baerlocher, C   Pattison, P
Synthesis and structure of Mu-33, a new layered aluminophosphate
   vertical bar((CH3)(3)CNH3+)(16)(H2O)(4)vertical bar[Al16P24O88(OH)(8)]
Mu-33, a new layered aluminophosphate with an Al/P ratio of 0.66, was
   obtained from a quasi non-aqueous synthesis in which
   tert-butylformamide (tBF) was the main solvent and only limited amounts
   of water were present. During the synthesis, tBF decomposed and the
   resulting protonated tert-butylamine is occluded in the as-synthesized
   material. The approximate structure was determined from data collected
   on a microcrystal (200 x 25 x 5 mu m(3)) at the European Synchrotron
   Radiation Facility (ESRF) in Grenoble, but the quality of these data
   did not allow satisfactory refinement. Therefore the structure was
   refined using high-resolution powder diffraction data, also collected
   at the ESRF. The structure (P2(1)/c, a = 9.8922(6) angstrom, b =
   26.180(2) angstrom, c = 16.729(1) angstrom and beta = 90.4(1)degrees)
   consists of anionic aluminophosphate layers that can be described as a
   six-ring honeycomb of alternating corner-sharing AlO4 and PO4
   tetrahedra with additional P-atoms above and below the honeycomb layer
   bridging between Al-atoms. The tert-butylammonium ions and water
   molecules located in the interlayer spacing interact via hydrogen-bonds
   with the terminal oxygens of the P-atoms. The characterization of this
   new aluminophosphate by C-13, P-31, H-1-P-31 heteronuclear correlation
   (HETCOR) and Al-27 3QMAS solid state NMR spectroscopy is also reported.


Dova, E   Peschar, R   Sakata, M   Kato, K   Schenk, H
High-spin- and low-spin-state structures of
   [Fe(chloroethyltetrazole)(6)](ClO4)(2) from synchrotron powder
   diffraction data
The spin-crossover complex [Fe(teeC)(6)](ClO4)(2) (teec =
   chloroethyltetrazole) exhibits a 50% incomplete spin crossover in the
   temperature range 300-30 K. Time-resolved synchrotron powder
   diffraction experiments have been carried out to elucidate its
   structural behavior. We report crystal structure models of this
   material at 300 K (high spin) and 90 K (low spin), as solved from
   synchrotron powder diffraction data by using Genetic Algorithm and
   Parallel Tempering techniques and refined with Rietveld refinement.
   During short synchrotron powder diffraction experiments (five minutes
   duration) two distinguishable lattices were observed the quantities of
   which vary with temperature. The implication of this phenomenon, that
   is interpreted as a structural phase transition associated with the
   high-tolow spin crossover, and the structural characteristics of the
   high-spin and low-spin models are discussed in relation to other
   compounds showing a similar type of spin-crossover behavior.


Hinrichsen, B   Dinnebier, RE   Rajiv, P   Hanfland, M
   Grzechnik, A   Jansen, M
Advances in data reduction of high-pressure x-ray powder diffraction
   data from two-dimensional detectors: a case study of Schafarzikite
Methods have been developed to facilitate the data analysis of multiple
   two-dimensional powder diffraction images. These include, among others,
   automatic detection and calibration of Debye-Scherrer ellipses using
   pattern recognition techniques, and signal filtering employing
   established statistical procedures like fractile statistics.
   All algorithms are implemented in the freely available program package
   Powder3D developed for the evaluation and graphical presentation of
   large powder diffraction data sets.
   As a case study, we report the pressure dependence of the crystal
   structure of iron antimony oxide FeSb2O4 ( p <= 21 GPa, T = 298 K)
   using high-resolution angle dispersive x-ray powder diffraction.
   FeSb2O4 shows two phase transitions in the measured pressure range. The
   crystal structures of all modifications consist of frameworks of Fe2+O6
   octahedra and irregular Sb3+O4 polyhedra. At ambient conditions,
   FeSb2O4 crystallizes in space group P4(2)/mbc ( phase I). Between p =
   3.2 GPa and 4.1 GPa it exhibits a displacive second order phase
   transition to a structure of space group P2(1)/c ( phase II, a =
   5.7792( 4) angstrom, b = 8.3134( 9) angstrom, c = 8.4545( 11) angstrom,
   beta = 91.879( 10)degrees, at p = 4.2 GPa). A second phase transition
   occurs between p = 6.4 GPa and 7.4 GPa to a structure of space group
   P4(2)/m ( phase III, a = 7.8498( 4) angstrom, c = 5.7452( 5) angstrom,
   at p = 10.5 GPa). A nonlinear compression behaviour over the entire
   pressure range is observed, which can be described by three Vinet
   equations in the ranges from p = 0.52 GPa to p = 3.12 GPa, p = 4.2 GPa
   to p = 6.3 GPa and from p = 7.5 GPa to p = 19.8 GPa. The extrapolated
   bulk moduli of the high-pressure phases were determined to K-0 = 49( 2)
   GPa for phase I, K-0 = 27( 3) GPa for phase II and K-0 = 45( 2) GPa for
   phase III. The crystal structures of all phases are refined against
   x-ray powder data measured at several pressures between p = 0.52 GPa,
   and 10.5 GPa.


Torres-Martinez, LM   Ibarra, J   Loredo, JR   Garza-Tovar, LL   Martinez-Bruno, O
Phase formation and crystal structure of ternary compound Na2Li2Ti6O14
SOLID STATE SCIENCES 8, 2006, 1281-1289.
A systematic study into phase formation in the system Na2O-Li2O-TiO2
   has been carried out at subsolidus temperatures, ca. 900-1000 degrees
   C. An. experimental study of compound formation and phase equilibrium
   in this ternary system for compositions containing > 50% TiO2 was made.
   Five ternary phases were encountered; three of them have variable
   composition. Solid solution called phase A, is centered on
   Na5.4Li1.6Ti6.5O16.5 (isostructural to Na0.68Ni0.34Ti0.66O2), phase B
   is centered on Na2Li2Ti6O14 (isostructural to SrLi2Ti6O14), and phase C
   is based on Na2LiTi8.5O18.5 (isostructural to Na2Fe2Ti6O16). Two
   ternary compounds were also found with composition:
   Na5.6Li2.8Ti5.8O15.8 and Na7Li3Ti5O15 (isostructural to
   Na0.75Fe0.75Ti0.25O2 and Na2.76Li1.24Ti2O6 respectively).
   The sodium lithium titanate with composition Na2Li2Ti6O14 has been
   synthesized by solid state reaction at 970 degrees C. The
   characterization was made by X-ray powder diffraction technique. The
   structure of Na2Li2Ti6O14 was solved using X-ray data (CuK alpha 1,2
   radiation), which were indexed using space group Cmca (64), with cell
   parameters a = 16.4749(1), b = 11.216 1 (1) and c = 11.4654(1). Crystal
   structure refinement was performed by means of Rietveld method, with
   the conventional factors R-wp = 19.2; R-exp = 14.40. Na2Li2Ti6O14 phase
   structure is described as a network of intercalated edge and
   comer-sharing distorted TiO6 octahedra. Na ions are surrounded by 11
   oxygen atoms, while Ti and Li atoms maintain a coordination of 6 and 4,
   respectively. This arrangement provides tunnels along the z-axis, in
   which the lithium atoms are located, forming distorted tetrahedra.


Goto, N   Fujihisa, H   Yamawaki, H   Wakabayashi, K   Nakayama, Y
   Yoshida, M   Koshi, MAF
Crystal structure of the high-pressure phase of
   hexahydro-1,3,5-trinitro-1,3,5-triazine (gamma-RDX)
JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 23655-23659.
The crystal structure of the high-pressure phase of
   hexahydro-1,3,5-trinitro-1,3,5-triazine (gamma-RDX), which is stable
   above 4 GPa at room temperature, was investigated by using infrared
   spectroscopy and powder X-ray diffraction measurements followed by
   Rietveld refinements using a diamond anvil cell (DAC). Although gamma
   and alpha phases were found to belong to the same space group Pbca,
   they exhibited a different crystal packing. The molecular structure of
   the gamma phase exhibited the same conformation as that of the alpha
   phase however, the torsion angles of N-NO2 changed marginally.


Santamaria-Perez, D   Haines, J   Amador, U   Moran, E   Vegas, A
Structural characterization of a new high-pressure phase of GaAsO4
As in SiO2 which, at high pressures, undergoes the alpha-quartz ->
   stishovite transition, GaAsO4 transforms into a dirutile structure at 9
   GPa and 1173 K. In 2002, a new GaAsO4 polymorph was found by quenching
   the compound from 6 GPa and 1273 K to ambient conditions. The powder
   diagram was indexed on the basis of a hexagonal cell (a = 8.2033, c =
   4.3941 A, V = 256.08 A(3)), but the structure did not correspond to any
   known structure of other AXO(4) compounds. We report here the ab initio
   crystal structure determination of this hexagonal polymorph from powder
   data. The new phase is isostructural to beta-MnSb2O6 and it can be
   described as a lacunary derivative of NiAs with half the octahedral
   sites being vacant, but it also contains fragments of the rutile-like


Day, GM   van de Streek, J   Bonnet, A   Burley, JC   Jones, W   Motherwell, WDS
Polymorphism of scyllo-inositol: Joining crystal structure prediction
   with experiment to elucidate the structures of two polymorphs
CRYSTAL GROWTH & DESIGN 6, 2006, 2301-2307.
We report on the crystal structures of two polymorphs of
   scyllo-inositol. Crystallization of this inositol initially failed to
   yield a single crystal suitable for structure solution, so a
   computational prediction of the low-energy forms was performed in
   parallel with the crystallization experiments. When a single crystal
   was finally grown, its structure failed to explain the powder X-ray
   diffraction pattern of the bulk material, which seemed to show a
   mixture of polymorphs. With the aid of the lowest-energy predicted
   crystal structure from a lattice energy search and the DASH program for
   structure solution from powder data, we propose the structure of the
   second polymorph. The combined use of single-crystal structure
   solution, structure solution from powder diffraction data, and a
   lattice energy search for possible structures, which was necessary for
   the elucidation of the second polymorph of scylloinositol, demonstrates
   the synergy between experimental and computational studies of molecular
   organic materials.


Berger, TG   Leineweber, A   Mittemeijer, EJ   Sarbu, C
   Duppel, V   Fischer, P
On the formation and crystal structure of the Pd6B phase
The crystal structure of the Pd6B phase has been elucidated employing
   selected-area electron diffraction and X-ray and neutron powder
   diffraction methods. It is based on a cubic close packed arrangement of
   Pd with B occupying 1/6 of the interstitial octahedral sites in an
   ordered way, such that a monoclinic (C2/c) superstructure results. The
   crystal structure contains isolated [BPd6] octahedral entities
   providing large distances between nearest neighbour boron atoms.
   Depending on the way of preparation, the same Pd6B phase can occur for
   the same composition in two different 'manifestations' having
   considerably different lattice parameters, which has a microstructural
   origin. Various phase equilibria between the ordered Pd6B phase and the
   disordered interstitial solid solution of boron in cubic close packed
   palladium have been investigated to clarify the corresponding regions
   in the phase diagram Pd-B.


Wallwork, KS   James, M   Carter, ML
The crystal chemistry, structure and properties of a synthetic
   carnotite-type compound, Ba-2[(UO2)(2)Ti2O8]
CANADIAN MINERALOGIST 44, 2006, 433-442.
The crystal structure of the carnotite-type compound Ba-2(UO2)(2)Ti2O8]
   has been determined by ab initio methods from synchrotron X-ray and
   neutron powder-diffraction data. We describe the first reported
   structure of a uranyl titanate; it was solved in the monoclinic
   space-group P2(1)/c and has the lattice parameters a 6.4463(1), b
   8.5999(1), c 10.2532(1) angstrom, beta 75.936(1)degrees, V 551.36(1)
   angstrom(3), D-calc, 6.253 g/cm(3) and Z = 4. A multiple histogram
   approach was used to refine the structure from synchrotron and
   neutron-diffraction data, giving quality factors of R-B 0.032 and
   0.039, R-wp 0.090 and 0.063, and R-p 0.070 and 0.049, respectively. The
   compound forms a layered structure in which sheets of uranyl pentagonal
   bipyramids share edges with dimers of TiO5 square pyramids. These are
   separated by layers of 11-fold-coordinated barium atoms. Because of the
   potential presence of Ba-2[(UO2)(2)Ti2O8] in ceramic waste-forms for
   the immobilization of radioactive wastes, the leach rate of uranium and
   barium were determined. The normalized rates of leaching from
   Ba-2[(UO2)(2)Ti2O8], averaged over seven days, are 1.3 X 10(-5) g/m(2)
   /day for uranium, a significantly lower rate than that observed from
   pyrochlore waste-forms, and 1 X 10(-4) g/m(2) /day for barium.


Papoular, RJ   Allouchi, H   Dzyabehenko, AV   Davydov, VA
   Rakhmanina, AV   Boltalina, OV   Seppelt, K   Agafonov, V
High-resolution X-ray powder diffraction structure determination of
Whereas previously reported X-ray powder diffraction experiments could
   be interpreted using an isotropic spherical two-shell model, our
   recently obtained data cannot. Rather, they were Rietveld-analyzed
   using three distinct anisotropic models for the C60F48 molecule
   featuring the S-6, D-3 and T-h molecular symmetries, respectively. The
   best fit was obtained for the D3 model, which is consistent with the
   F-19 NMR characterization of our sample. The chi(2) dependence upon the
   Euler angles of the (CF48)-F-60 molecule is found to be substantial.
   The unit


Brugger, J   Wallwork, KS   Meisser, N   Pring, A   Ondrus, P   Cejka, J
Pseudojohannite from Jachymov, Musonoi, and La Creusaz: A new member of
   the zippeite-group
AMERICAN MINERALOGIST 91, 2006, 929-936.
Pseudojohannite is a hydrated copper(II) uranyl sulfate described from
   Jachymov, Northern Bohemia, Czech Republic (type locality).
   Pseudojobannite also occurs at the Musondi quarry near Kolwezi, Shaba,
   Congo, and the La Creusaz prospect, Western Swiss Alps. At all three
   localities. pseudojohannite formed through the interaction of acid
   sulfate mine drainage waters with uraninite (Jachymov and La Creusaz)
   or uranyl silicates (Musondi). Pseudojohannite forms moss green, non
   UV-fluorescent aggregates consisting of irregularly shaped crystals
   measuring up to 25 pm in length and displaying an excellent cleavage
   parallel to (1) over bar 01). d(meas) is 4.31 g/cm(3), d(calc) 4.38
   g/cm(3). and the refractive indices are n(min) = 1.725 and n(max) =
   A high-resolution synchrotron powder diffraction pattern on the
   material from Musondi shows that pseudojohannite is triclinic (P1 or P
   (1) over bar), with a = 10.027(1) angstrom, b = 10.822(1) angstrom, c =
   13.396(1) angstrom, alpha = 87.97(1)degrees, beta = 109.20(1)degrees,
   gamma = 90.89(1)degrees, V = 1371.9(5) angstrom(3). The location of the
   uranium and sulfur atoms in the cell was obtained by direct methods
   using 1807 reflections extracted from the powder diffractogram.
   Pseudojohannite contains zippeite-type layers oriented parallel to ((1)
   over bar 01). The empirical chemical formula calculated for a total of
   70 0 atoms is Cu6.52U7.85S4.02O70H55.74, leading to the simplified
   chemical formula Cu-6.5[(UO2)(4)O-4(SO4)(2)](2)(OH)(5)(.)25H(2)O. The
   distance of 9.16 angstrom between the uranylsulfate sheets in
   pseudojohannite shows that neighboring layers do not share 0 atoms with
   the same Cu Phi(6) [Phi = (O,OH)] distorted octahedrons, such as in
   magnesium-zippeite. Rather, it is expected that Cu Phi(6) forms a layer
   bound to the zippeite-type layers by hydrogen bonding, as in
   marecottite, or one apex of the Cu Phi(6)polyhedron only is shared with
   a zippeite-type layer, as in synthetic SZIPPMg. The higher number of
   cations in the interlayer of pseudojohannite (Cu:S = 1.6:1) compared to
   marecottite (3:4) and SZIPPMg (1: 1) indicates that pseudojohannite has
   a unique interlayer topology.
   Ab-initio powder structure solution techniques can be used to obtain
   important structural information on complex micro-crystalline minerals
   such as those found in the weathering environment. Pseudojohannite
   represents a new member of the zippeite group of minerals, and further
   illustrates the structural complexity of zippeite-group minerals
   containing divalent cations, which have diverse arrangements in the
   interlayer. Peudojohannite and other divalent zippeites are common,
   easily overlooked minerals in acid drainage environments around uranium
   deposits and wastes.


Barnes, PW   Lufaso, MW   Woodward, PM
Structure determination of A(2)M(3+)TaO(6) and A(2)M(3+)NbO(6) ordered
   perovskites: octahedral tilting and pseudosymmetry
The room-temperature crystal structures of six A(2)M(3+) M5+O6 ordered
   perovskites have been determined from neutron and X-ray powder
   diffraction data. Ba2YNbO6 adopts the aristotype high-symmetry cubic
   structure (space group Fm (3) over barm, Z = 4). The symmetries of the
   remaining five compounds were lowered by octahedral tilting
   distortions. Out-of-phase rotations of the octahedra about the c axis
   were observed in Sr2CrTaO6 and Sr2GaTaO6, which lowers the symmetry to
   tetragonal (space group = I4/ m, Z = 2, Glazer tilt system =
   a(0)a(0)c(-)). Octahedral tilting analogous to that seen in GdFeO3
   occurs in Sr2ScNbO6, Ca2AlNbO6 and Ca2CrTaO6, which lowers the symmetry
   to monoclinic (space group P2(1)/ n, Z = 2, Glazer tilt system =
   a(-)a(-)c(+)). The Sr2MTaO6 (M = Cr, Ga, Sc) compounds have unit- cell
   dimensions that are highly pseudocubic. Ca2AlNbO6 and Ca2CrTaO6 have
   unit- cell dimensions that are strongly pseudo-orthorhombic. This high
   degree of pseudosymmetry complicates the space- group assignment and
   structure determination. The space-group symmetries, unitcell
   dimensions and cation ordering characteristics of an additional 13
   compositions, as determined from X- ray powder diffraction data, are
   also reported. An analysis of the crystal structures of 32 A(2)MTaO(6)
   and A(2)MNbO(6) perovskites shows that in general the octahedral tilt
   system strongly correlates with the tolerance factor.


Stahly, GP   Bates, S   Andres, MC   Cowans, BA
Discovery of a new polymorph of dehydroepiandrosterone (prasterone) and
   solution of its crystal structure from X-ray powder diffraction data
CRYSTAL GROWTH & DESIGN 6, 2006, 925-932.
A new polymorph of dehydroepiandrosterone, also known as DHEA or
   prasterone, was found and designated form FVI. Form FVI is anhydrous
   and nonsolvated, and is less thermodynamically stable than the known
   form FI under ambient conditions. The X-ray powder diffraction patterns
   of FI and FVI are so similar that this technique is inadequate to
   determine if samples contain pure FI, pure FVI, or mixtures of the two.
   However, the forms can be differentiated by solid-state NMR
   spectroscopy. The crystal structure of FVI was determined from X-ray
   powder diffraction data using a combination of proprietary SSCI
   software and the Cambridge Crystallographic Data Centre's program DASH.


Vivani, R   Costantino, F   Costantino, U   Nocchetti, M
New architectures for zirconium polyphosphonates with a tailor-made
   open-framework structure
INORGANIC CHEMISTRY 45, 2006, 2388-2390.
The use of tetraphosphonic building blocks for the preparation of
   inorganic-organic zirconium derivatives has led to the formation of
   novel compounds with a modular structure. This is based on the
   different connection of polymeric 1 D inorganic units covalently
   connected by organic groups. The different kinds of connections
   generate two different open-framework structures. These structures have
   been solved "ab initio" by powder X-ray diffraction data. Very likely,
   the dimensions of the channels inside these structures may be tuned by
   the right choice of the interlinking organic group.


Fernandez-Carrasco, L   Rius, J
Synthesis and crystal structure determination of hydrated potassium
   dawsonite from powder diffraction data
During the optimisation of the synthesis conditions of non-hydrated
   potassium dawsonite, a compound which has been recently shown to be
   involved in the alkaline hydrolysis of calcium aluminate cement (CAC),
   a new closely related hydrated phase appearing below T = 25 degrees C
   was detected by powder X-ray diffraction. To gain a more complete
   understanding of the crystal chemistry of CAC, this new phase was
   synthesised in pure form and its crystal structure solved from powder
   X-ray diffraction data. The crystal data are a = 8.3312(4), b =
   11.2670(5), c = 5.661(2)angstrom, Pna2(1) (No. 33) and the resulting
   chemical formula is KAl(CO3)(OH)(2) .  H2O with Z = 4. From the
   refined positions of the non-hydrogen atoms and from the balance of
   bond valences, the chemical nature of the 0 atoms could be univocally
   established [R-wp = 0.132, R-B = 0.056, Chi(2) = 1.15]. The unit cell
   of this hydrated compound contains two carboaluminate chains formed by
   the basic unit [Al-2(OH)(4)(CO3)(2)](2-) propagating along the c axis
   and being stabilised by a complex H-bond network. The arrangement of
   these chains is similar to that found in dawsonite, so that the atomic
   positions of K+ and Na+ in both structures are also similar. As
   confirmed by the X-ray diffraction study of a one-year-old sample,
   hydrated potassium dawsonite slowly transforms into the non-hydrated
   form at room temperature. Due to the more favourable formation
   conditions, i.e. lower temperature and higher humidity, this hydrated
   phase could be eventually found in CAC pastes or mortars.


Dorset, DL   Weston, SC   Dhingra, SS
Crystal structure of zeolite MCM-68: A new three-dimensional framework
   with large pores
The crystal structure of the aluminosilicate MCM-68 was solved from
   synchrotron powder diffraction data by the program FOCUS. The unit cell
   framework contains Si100.6Al11.4O224. This material crystallizes in
   space group P4(2)/mnm, where, after Rietveld refinement, a = 18.286(1)
   angstrom and c = 20.208(2) angstrom. A three-dimensional framework is
   found that contains continuous 12-ring channels and two orthogonal,
   intersecting, undulating 10-ring channels. Rietveld refinement of the
   model coordinates optimizes the framework geometry, to match the
   observed intensity profile by R-wp, = 0.1371, R(F-2) = 0.1411. It is
   not possible to determine the location of approximately 0.84 K+ cations
   remaining in the unit cell after the material is steamed and then
   dehydrated. The framework model also successfully predicts observed
   electron diffraction data in two projections, and the tetragonal
   projection can be determined independently from these data by direct
   methods. The calculated density of the framework structure is 1.66
   g/cm(3), and the T-site framework density is 16.6 T/1000 angstrom(3).


Gualtieri, AF   Ferrari, S   Galli, E   Di Renzo, F   van Beek, W
Rietveld structure refinement of zeolite ECR-1
CHEMISTRY OF MATERIALS  18, 2006, 76-84.
In this work, we present the structure refinement of ECR-1 to give the
   first direct evidence of the proposed structure of this synthetic
   zeolite. In fact, a model of the structure of ECR-1 was proposed on the
   basis of high-resolution transmission electron microscopy (HRTEM)
   evidence and the structure solution of the synthetic gallo-silicate
   TNU-7, but it has not been refined to date. The proposed model consists
   of structure layers of mordenite (MOR) and mazzite (MAZ) connected in a
   regular 1: 1 stacking sequence and framework topology EON. Because
   single crystals of ECR-1 cannot be synthesized, the structure was
   refined using the Rietveld method. High-resolution synchrotron powder
   diffraction data were collected on both the synthetic Na-ECR-1 and
   NH4-ECR-1 samples at ESRF. Na atoms located on the axis of the
   eight-member ring channels in mordenite and zeolite omega are not
   present in Na-ECR-1. In Na-ECR-1, the equivalent sites lay near the
   walls of the eight-membered-ring channels. This difference is
   presumably at the basis of the formation of ECR-1 because, during
   growth, the local symmetry deformation of the eight-membered-ring
   channel prevents the formation of the MOR or MAZ structures and justify
   the periodical shift from one structure to the other. A quantitative
   explanation of the anisotropic peak broadening observed in the powder
   patterns is also given.


Paglia, G   Bozin, ES   Vengust, D   Mihailovic, D   Billinge, SJL
Accurate structure determination of Mo6SyIz nanowires from atomic pair
   distribution function (PDF) analysis
CHEMISTRY OF MATERIALS 18, 2006, 100-106.
The structure of the recently discovered systematically reproducible
   Mo6SyI7 nanowires has been determined from the atomic pair distribution
   function (PDF) analysis of powder X-ray diffraction data. This total
   scattering approach was required because the nanowires are not
   perfectly crystalline and, therefore, the structure cannot be obtained
   crystallographic ally. Several nanotube and nanowire models were fit to
   the PDF data. The resulting best-fit model structure consists of
   nanowires Of Mo-6 octahedra that are bridged by sulfur and terminated
   on the outside by iodine. This demonstrates the power of total
   scattering methods in accurately resolving structural issues in
   nanostructured materials where traditional crystallographic methods


Giunchi, G   Malpezzi, L   Masciocchi, N
A new crystalline phase of the boron-rich metal-boride family: the
   Mg2B25 species
SOLID STATE SCIENCES 8, 2006, 1202-1208.
A new complex magnesium boride, the Mg2B25 species, has been prepared
   and its crystal structure determined from laboratory X-ray powder
   diffraction data by the simulated annealing technique, followed by a
   conventional Rietveld refinement procedure. The title compound is
   R-centered trigonal (with a = 11.0402(3) angstrom and c = 24.198(1)
   angstrom, hexagonal setting), space group R-3m, and is isomorphous with
   beta-boron and with the rhombohedral compounds of the boron-rich
   metal-boride family. The magnesium atoms occupy interstitial sites with
   partial occupancies which can be interpreted with the aid of the
   analysis of "forbidden" interatomic Mg-Mg contacts. The Mg atom in the
   F site is vicariant with the B(4) atom and falls into a
   pseudometallocenic environment with the 10 nearest-neighbour B atoms;
   all other magnesium atoms are placed in lattice cavities within
   corrugated slabs normal to c, with Mg(D) and Mg(E) occupying sites
   already known to be populated in other metal borides, and Mg(N) in a
   new one. These slabs present two equiprobable, but self excluding,
   configurations of ordered Mg atoms, which randomly stack along the
   c-axis. Mg2B25 shows a significant increase of the c-axis of the
   rhombohedral lattice with respect to the other members of the family,
   which we attribute both to the larger metallic radius of Mg, vs. those
   of 3d transition metal atoms and to the anisotropic stacking of the Mg
   atoms, and, possibly, to the presence of the rather stuffed Mg


Masciocchi, N   Galli, S   Alberti, E   Sironi, A   Di Nicola, C
   Pettinari, C   Pandolfo, L
Synthesis, solid-state NMR, and X-ray powder diffraction
   characterization of group 12 coordination polymers, including the first
   example of a C-mercuriated pyrazole
INORGANIC CHEMISTRY 45, 2006, 9064-9074.
Cadmium and mercury acetates have been reacted with pyrazole (Hpz) and
   3,5-dimethylpyrazole (Hdmpz), affording distinct mixed-ligand species,
   selectively prepared upon slightly modifying the reaction conditions.
   Two polymorphs of [{Cd(mu-ac)(2)(Hpz)(2)}(n)], as well as the
   [{Cd(mu-ac)(2)(Hdmpz)(2)}(n)] species (Hac = acetic acid), were
   obtained by solution chemistry, while the two-dimensional
   [{Cd-3(mu(3)-ac)(4)(mu-pz)(2)(Hpz)(2)}(n)] and [{Cd(mu-ac)(mu-pz)}(n)]
   polymers were prepared upon controlled thermal treatment of one of the
   [{Cd(mu-ac)(2)(Hpz)(2)}(n)] forms. Two mercury derivatives,
   [{Hg-3(mu-ac)(3)(mu-pz)(3)}(n)] and [{Hg(ac)(mu-dmpz)}(n)], were also
   prepared, the latter containing one-dimensional chains of Hg(II) ions
   bridged by C-mercuriated Hdmpz ligands. All their crystal structures
   (but one) were determined by powder diffraction methods using
   conventional X-ray laboratory equipment, supported by C-13 CPMAS NMR
   measurements. The latter method helped in assigning a C-metalated
   nature to an amorphous material of [Hg(ac)-( pz)] formula, obtained by
   employing EtOH as a solvent. A few other Hdmpz-containing cadmium
   acetates were also prepared, but their polyphasic nature, evidenced by
   diffraction methods, hampered their complete structural


Navarro, JAR   Barea, E   Salas, JM   Masciocchi, N   Galli, S
   Sironi, A   Ania, CO   Parra, JB
H-2, N-2, CO, and CO2 sorption properties of a series of robust
   sodalite-type microporous coordination polymers
INORGANIC CHEMISTRY 45, 2006, 2397-2399.
H-2, N-2, CO, and CO2 are readily incorporated in the porous, 3D
   sodalitic frameworks of coordination polymers of the [ML2](n) type,
   with M = Pd-II or Cu-II and HL = 2-hydroxypyrimidine or
   4-hydroxypyrimidine. The metal ion and ligand functionalization
   modulate their sorption properties, making these materials suitable for
   gas storage and separation purposes.


Barbier, J   Cranswick, LMD
The non-centrosymmetric borate oxides, MBi2B2O7 (M = Ca, Sr)
Two novel noncentrosymmetric berates oxides, MBi2B2O7 or MBi2O(BO3)(2)
   (M=Ca, Sr), have been synthesized by solid-state reactions in air at
   temperatures in the 600-700 degrees C range. Their crystal structures
   have been determined ab initio and refined using powder neutron
   diffraction data. CaBi2B2O7 crystallizes in the orthorhombic Pna2(1)
   space group with a = 8.9371(5)angstrom, b = 5.4771(3)angstrom, c =
   12.5912(7) angstrom, Z = 4, R-wp = 0.118, chi(2) = 2.30, SrBi2B2O7
   crystallizes in the hexagonal P6(3) space group with a = 9.1404(4)
   angstrom, c = 13.0808(6) angstrom, Z = 6, R-wp = 0.115, chi(2) = 4.15.
   Large displacement parameters suggest the presence of disorder in
   SrBi2B2O7 as also revealed by diffuse 2 x a superstructure reflections
   in electron diffraction patterns. Both structures are built of
   identical (001) neutral layers of corner-sharing BO3 triangles and MO6
   trigonal prisms forming six-membered rings in which Bi2O groups are
   located. Adjacent layers are stacked in a staggered configuration and
   connected through weak Bi-O bonds. A moderate efficiency for second
   harmonic generation (SHG) has been measured for a powder sample of
   CaBi2B2O7 (d(eff) = 2d(eff)(KDP)).
FOX, Fullprof


Tobbens, DM   Kahlenberg, V   Gspan, C   Kothleitner, G
Atomic and domain structure of the low-temperature phase of barium
   metagermanate (BaGeO3)
The crystal structure of the low-temperature form of barium
   metagermanate (BaGeO3) has been determined from laboratory X-ray powder
   diffraction data collected at 298.5 (5) K. The structure was found to
   consist of alternating layers of Ba cations and [GeO3](3) rings, and is
   closely related to pseudowollastonite. The rings show a twofold
   positional disorder owing to stacking faults. The stacking is not
   random, but can be rationalized by a twinning mechanism mapping the two
   non-congruent enantiomorphic polytypes of the structure onto each
   other. This model also explains the diffuse scattering and twinning
   observed in SAED and HRTEM, as well as the size and strain-like
   broadening effects found in the XRPD pattern.


Tobbens, DM   Kaindl, R   Kahlenberg, V   Schottenberger, H   Hummel, M
The homoleptic square-antiprismatic chelate
   tetrakis(3-acetyl-2,4-pentanedionato)zirconium(IV): A promising
   coordination motif for tetrahedral metal-organic frameworks
CRYSTAL GROWTH & DESIGN, 6, 2006, 1720-1725.
The novel analogue of the parent Zr(acac)(4) complex,
   tetrakis(3-acetyl-2,4-pentanedionato) zirconium(IV), Zr[C7O3H9](4), has
   been synthesized straightforwardly by a salt-free methodology and was
   characterized by a number of complementary methods (H-1 NMR, C-13 NMR,
   IR, and bulk density). From polycrystalline material, X-ray powder
   diffractograms and micro-Raman spectra were obtained and are discussed
   in detail. The crystal structure was determined from laboratory X-ray
   powder diffraction data by simulated annealing and subsequently refined
   with the Rietveld technique. The compound is monoclinic with space
   group P2/c. Zr, residing on a crystallographic 2-fold rotation axis, is
   coordinated by the four chelating ligands forming a
   square-antiprismatic coordination polyhedron. Differences and
   similarities to zirconium(IV) acetylacetonate, Zr[C5O2H7](4), and other
   similar complexes are discussed, addressing the conformational rigidity
   of this symmetrically substituted homoleptic acac complex.

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Armel Le Bail