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.
TREOR
2006-2
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
diffraction
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3087-3094
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
TREOR
2006-3
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
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3214-3223
2,4,6-trimethoxybenzaldehyde,
2,4,6-trimethoxybenzyl alcohol,
2,4,6-trimethoxyacetophenone
powder X-ray diffraction data,
direct-space Genetic Algorithm (GA) technique for structure solution
followed by Rietveld refinement.
TREOR
2006-4
Kahlenberg, V Kaindl, R Tobbens, DM
The crystal structure of the interrupted framework silicate
K9.6Ca1.2Si12O30 determined from laboratory X-ray diffraction
data
JOURNAL OF SOLID STATE CHEMISTRY, 179, 2006, 1948-1956.
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,
TREOR/DICVOL
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]
JOURNAL OF ALLOYS AND COMPOUNDS, 418, 2006, 90-94.
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.
TREOR
2006-8
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
CRYSTAL RESEARCH AND TECHNOLOGY, 41, 2006, 588-594.
1,8-bis(dimethylamino)naphthalene.HI
P2(1)/c
TREOR
2006-9
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.
TREOR
2006-10
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
ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 221, 2006, 270-275.
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.
P2(1)/n)
laboratory X-ray sources.
TREOR
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
SO CHEMISTRY-A EUROPEAN JOURNAL 12, 2006, 3515-3527.
CHOLESTEROL MONOHYDRATE
direct-space
approach employing the Monte Carlo method with the Rietveld
refinement
for the structure solution from the powder X-ray diffraction
data.
TREOR
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
[Pt-2(L)(CO)(2)]
ORGANOMETALLICS 25, 2006, 2253-2265.
a powder X-ray diffraction analysis has been performed on
complex [Pt-2(L)(CO)(2)].
TREOR
2006-12
Guo, F Cheung, EY Harris, KDM Pedireddi,
VR
Contrasting solid-state structures of trithiocyanuric acid and cyanuric
acid
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.
TREOR
2006-13
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.
TREOR, DICVOL,
2006-14
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.
cis-[CoBr(NH3)(en)(2)]Br-2
structure determination from powder X-ray diffraction data,
TREOR, N-TREOR,
2006-15
Albov, DV Jassem, A Kuznetsov, AI
An independent refinement of H-atom coordinates from laboratory X-ray
powder data in tetraformaltrisazine
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006,
O1449-O1451.
ID PROGRAM
tetraformaltrisazine (systematic name:
1,2,3,4,5,6,7,8-octahydro-1,2,4,5-tetrazino-[1,2-a][1,2,4,5]tetrazine),
C4H12N6,
has been solved by simulated annealing from X-ray laboratory
powder data and refined by Rietveld refinement without
any restraints
for non-H atoms.
TREOR
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
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 3669-3676.
microcrystalline Pb[Au(CN)(2)](2) (2).
a structure is proposed on the basis of the NMR and X-ray powder data,
TREOR
2006-17
Stowasser, F Renkenberger, C
Ab initio crystal structure determination of Bi6Rh12O29 from powder
diffraction data
ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 221, 2006, 206-212
simulated annealing
Bi6Rh12O29 C2/m, Z = 4
laboratory X-ray powder diffraction data
with the software package TOPAS
TREOR
2006-18
Kongshaug, KO Fjellvag, H
Design of novel bilayer compounds of the CPO-8 type containing 1D channels
INORGANIC CHEMISTRY 45, 2006, 2424-2429.
CPO-8-BPY
([Zn(C8H5NO4)(ClOH8N2)(0.5)] . 3nH(2)O),
CPO-8-DPE
([Zn(C8H5NO4)(Cl2H10N2)(0.5)](n) . 2.5nH(2)O),
CPO-8-DPA
([Zn(C8H5NO4)(Cl2H12N2)(0.5)](n) . 2.5nH(2)O), and
CPO-8-DPP
([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.
TREOR
2006-19
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
ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 221, 2006, 115-121.
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.
TREOR
2006-20
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),
Mn-III(OH)(O3PCH2CH2COOH)(H2O)-H-.(2),
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.
TREOR
2006-21
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
JOURNAL OF SOLID STATE CHEMISTRY
Mn(SeO3) H2O
solved from X-ray powder diffraction data.
TREOR
2006-22
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.
DICVOL
2006-23
Hulme, AT Fernandes, P Florence, A
Johnston, A Shankland, K
Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione 1-methylnaphthalene
hemisolvate
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006,
O3752-O3754.
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.
DICVOL
2006-24
Llinas, A Fabian, L Burley, JC van
de Streek, J Goodman, JM
Amodiaquinium dichloride dihydrate from laboratory powder diffraction
data
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006,
O4196-O4199.
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.
DICVOL
2006-25
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.
DICVOL
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
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 4932-4936.
DICVOL
2006-27
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
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3591-3598.
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.
N-TREOR
2006-28
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
JOURNAL OF MOLECULAR STRUCTURE 791, 2006, 41-52.
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.
DICVOL
2006-29
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
MATERIALS RESEARCH BULLETIN 41, 2006, 1550-1557.
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.
DICVOL
2006-30
Ibberson, RM
The low-temperature phase III structure and phase transition behaviour
of cyclohexanone
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 592-598.
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.
DICVOL
2006-31
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
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 606-611.
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.
DICVOL
2006-32
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
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 627-633.
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
groups.
DICVOL
2006-33
Hulme, AT Fernandes, P Florence, A
Johnston, A Shankland, K
Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione form 2
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006,
O3046-O3048.
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.
DICVOL
2006-34
Cerny, R Renaudin, G Tokaychuk, Y
Favre-Nicolin, V
Complex intermetallic compounds in the Mg-Ir system solved by powder
diffraction
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.
DICVOL, FOX
2006-35
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.
DICVOL
2006-36
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.
DICVOL
2006-37
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.
DICVOL
2006-38
Fernandes, P Florence, AJ Shankland, K
Shankland, N Johnston, A
Powder study of chlorothiazide N,N-dimethyl-formamide solvate
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006,
O2216-O2218
The crystal structure of the title compound [systematic name:
6-chloro-4H-1,2,4-benzothia-diazine-7-sulfonamide
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.
DICVOL
2006-39
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
JOURNAL OF SOLID STATE CHEMISTRY, 179, 2006, 1323-1329.
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.
DICVOL
2006-40
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.
DICVOL
2006-41
Wu, L Chen, XL Zhang, Y Kong, YF
Xu, JJ Xu, YP
Ab initio structure determination of novel borate NaSrBO3
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 1219-1224.
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
here.
DICVOL
2006-42
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,
Sr)
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.
DICVOL
2006-43
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 =
1479.90(1)angstrom(3).
DICVOL
2006-44
Hemono, N Rocherulle, J Le Floch, M
Bureau, B
Synthesis, characterization and devitrification behaviour of an yttrium
containing boroaluminate glass
JOURNAL OF MATERIALS SCIENCE 41, 2006, 445-453.
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).
DICVOL
2006-45
Ibberson, RM Telling, MTF Parsons, S
Structure determination and phase transition behaviour of dimethyl
sulfate
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 280-286.
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.
DICVOL
2006-46
Haynes, DA Van de Streek, J Burley, JC
Jones, W Motherwell, WDS
Pamoic acid determined from powder diffraction data
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006,
O1170-O1172.
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.
DICVOL
2006-47
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
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 1547-1552.
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.
DICVOL
2006-48
Burley, JC van de Streek, J Stephens, PW
Ampicillin trihydrate from synchrotron powder diffraction data
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006,
O797-O799.
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.
DICVOL
2006-49
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)
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 130-130.
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).
DICVOL
2006-50
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
JOURNAL OF APPLIED CRYSTALLOGRAPHY, 39, 2006, 1-5.
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.
DICVOL
2006-51 ??
Chotard, JN Filinchuk, Y Revaz, B
Yvon, K
Isolated [Ni2H7](7-) and [Ni4H12](12-) ions in La2MgNi2H8
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 7770-7773.
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)
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 15592-15593.
2006-53
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]
ACTA CRYSTALLOGRAPHICA SECTION C 62, 2006, M607-M609.
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
chains.
2006-54
Tyutyunnik, AP Zubkov, VG Tarakina, NV
Krasil'nikov, VN
Perelyaeva, LA Baklanova, IV Svensson,
G
Synthesis, crystal structure and vibrational spectra of KCrV2O7 and
RbCrV2O7
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.
2006-56
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.
2006-57
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.
2006-58
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
reorganization.
2006-59
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
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 14889, 14896.
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.
2006-60
van Mechelen, JB Peschar, R Schenk, H
Structures of mono-unsaturated triacylglycerols. I. The beta(1)
polymorph
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 1121-1130.
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.
2006-61
van Mechelen, JB Peschar, R Schenk, H
Structures of mono-unsaturated triacylglycerols. II. The beta(2)
polymorph
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 1131-1138.
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.
2006-62
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
JOURNAL OF THE AMERICAN CERAMIC SOCIETY 89, 2006, 3462-3469.
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.
2006-63
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.
2006-64
Boulineau, A Joubert, JM Cerny, R
Structural characterization of the Ta-rich part of the Ta-Al system
JOURNAL OF SOLID STATE CHEMISTRY, 179, 2006, 3385-3393.
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.
2006-65
Barrier, N Malo, S Hernandez, O
HervieUa, M Hervieu, M Raveau, B
The mixed valent tellurate SrTe3O8: Electronic lone pair effect of
Te4+
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3484-3488.
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+
cations.
2006-66
Chong, SY
Seaton, CC Kariuki, BM Tremayne,
M
Molecular versus crystal symmetry in tri-substituted triazine, benzene
and isocyanurate derivatives
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 864-874.
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.
2006-67
Sugimoto, K Dinnebier, RE Schlecht, T
Chlorartinite, a volcanic exhalation product also found in industrial
magnesia screed
JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 738-744.
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.
2006-68
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.
2006-69
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.
2006-70
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+.
2006-71
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
NaVOPO4.
2006-72
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)
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 4505-4508.
2006-74
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.
2006-75
Aitasalo, T Holsa, J Laamanen, T
Lastusaari, M
Lehto, L Niittykoski, J Pelle,
F
Crystal structure of the monoclinic Ba2MgSi2O7 persistent luminescence
material
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.
2006-76
Perchiazzi, N
Crystal structure determination and Rietveld refinement of rosasite
and
mcguinnessite
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.
2006-77
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.
2006-78
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)
MATERIALS RESEARCH BULLETIN 41, 2006, 1170-1177.
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.
2006-79
Hofmann, DWM Kuleshova, LN
A method for automated determination of the crystal structures from
X-ray powder diffraction data
CRYSTALLOGRAPHY REPORTS 51, 2006, 419-427.
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).
2006-80
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.
2006-81
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
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY iss 8, 2006, 1662-1669.
[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.
2006-82
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
JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 5975-5983.
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.
2006-83
Schmidt, MU Hofmann, DWM Buchsbaum, C
Metz, HJ
Crystal structures of pigment Red 170 and derivatives, as determined
by
X-ray powder diffraction
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 1313-1317.
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
diffraction
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 15554-15555.
2006-85
Sorby, MH Gunnaes, AE Lovvik, OM
Brinks, HW Fjellvag, H Hauback, BC
The crystal structure of Zr2NiD4.5
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 972-978.
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.
2006-86
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.
2006-87
Lufaso, MW Macquart, RB Lee, Y Vogt,
T zur Loye, HC
Structural studies of Sr2GaSbO6, Sr2NiMoO6, and Sr2FeNbO6 using
pressure and temperature
JOURNAL OF PHYSICS-CONDENSED MATTER 18, 2006, 8761-8780.
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.
2006-88
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
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 67, 2006, 1612-1617.
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
discussed.
2006-89
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
JOURNAL OF MATERIALS CHEMISTRY 16, 2006, 3609-3618.
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.
2006-90
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
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 67, 2006, 1416-1422.
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.
2006-92
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
system
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 8862-8867.
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.
2006-93
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
analysis
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.
2006-94
Kirik, SD Starkov, AK Kozhuhovskay, GA
cis-Amminedichloroisopropylamine-platinum(II) by X-ray powder
diffraction analysis
ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 62,
2006, M249-M251.
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.
2006-95
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.
2006-96
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.
2006-97
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.
2006-98
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
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 467-473.
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.
2006-99
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.
2006-100
Leineweber, A Nitsche, H
La5Al3Ni2 - an intermetallic phase observed upon crystallization of
La50Al25Ni25 metallic glass
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 632, 2006, 553-558.
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.
2006-101
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
JOURNAL OF PHYSICAL CHEMISTRY A 110, 2006, 3010-3016.
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.
2006-102
Yang, XB
Synthesis and crystal structure of tetramethylammonium fluoride
octadecasil
MATERIALS RESEARCH BULLETIN 41, 2006, 54-66.
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.
2006-103
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.
2006-104
Fukuda, K Wata, T Niwa, T
Crystal structure and phase transformations of calcium yttrium
orthophosphate, Ca3Y(PO4)(3)
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3420-3428.
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.
2006-105
Stephenson, GA Liang, C
Structural determination of the stable and meta-stable forms of
atomoxetine HCl using single crystal and powder X-ray
diffraction
methods
JOURNAL OF PHARMACEUTICAL SCIENCES 95, 2006, 1677-1683.
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.
2006-106
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.
2006-107
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
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 1053-1059
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.
2006-108
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.
2006-109
Karray, R Kabadou, A Ben Salah, A
van der Lee, A
X-ray powder diffraction study of cesium ammonium hexachlorotellurate
[Cs-0.86(NH4)(0.14)](2)TeCl6
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.
2006-110
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
JOURNAL OF PHARMACEUTICAL SCIENCES 95, 2006, 2123-2136.
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
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 6013-6016.
2006-112
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.
2006-113
Sassoye, C de Kozak, A
Crystal structure and thermal behaviour of K-2[CrF5 . H2O]
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 632, 2006, 445-448.
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.
2006-114
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)]
MICROPOROUS AND MESOPOROUS MATERIALS 90, 2006, 5-15.
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.
2006-115
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
CHEMISTRY-A EUROPEAN JOURNAL 12, 2006, 5043-5052.
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.
2006-116
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
(FeSb2O4)
JOURNAL OF PHYSICS-CONDENSED MATTER 18, 2006, S1021-S1037.
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.
2006-117
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.
2006-118
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.
2006-119
Santamaria-Perez, D Haines, J Amador, U
Moran, E Vegas, A
Structural characterization of a new high-pressure phase of GaAsO4
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 1019-1024.
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
structure.
2006-120
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.
2006-121
Berger, TG Leineweber, A Mittemeijer, EJ
Sarbu, C
Duppel, V Fischer, P
On the formation and crystal structure of the Pd6B phase
ZEITSCHRIFT FUR KRISTALLOGRAPHIE 221, 2006, 450-463.
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.
2006-122
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.
2006-123
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
C60F48
FULLERENES NANOTUBES AND CARBON NANOSTRUCTURES 14, 2006, 279-285.
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
2006-124
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) =
1.740.
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.
2006-125
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
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 384-396.
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.
2006-126
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.
2006-127
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.
2006-128
Fernandez-Carrasco, L Rius, J
Synthesis and crystal structure determination of hydrated potassium
dawsonite from powder diffraction data
EUROPEAN JOURNAL OF MINERALOGY 18, 2006, 99-104.
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.
2006-129
Dorset, DL Weston, SC Dhingra, SS
Crystal structure of zeolite MCM-68: A new three-dimensional framework
with large pores
JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 2045-2050.
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).
2006-130
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.
2006-131
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
fail.
2006-132
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
sublattices.
2006-133
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
characterization.
2006-134
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.
2006-135
Barbier, J Cranswick, LMD
The non-centrosymmetric borate oxides, MBi2B2O7 (M = Ca, Sr)
JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3958-3964.
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)).
reserved.
FOX, Fullprof
2006-136
Tobbens, DM Kahlenberg, V Gspan, C
Kothleitner, G
Atomic and domain structure of the low-temperature phase of barium
metagermanate (BaGeO3)
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 1002-1009.
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.
FOX
2006-137
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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