Beckmann, J Costantino, F Dakternieks, D
Duthie, A Ienco, A
Midollini, S Mitchell, C Orlandini,
A Sorace, L
Inorganic-organic hybrids of the p,p '-diphenylmethylenediphosphinate,
pcp(2-). Synthesis, characterization, and XRPD structures
of [Sn(pcp)]
and [Cu(pcp)]
INORGANIC CHEMISTRY 44, 2005, 9416-9423.
Two new inorganic-organic polymeric hybrids
[Sn(pcp)] and [Cu(pcp)], pcp = CH2(PhPO2)(2)(2-),
solved "ab initio" by X-ray powder diffraction (XRPD) data.
TREOR
2005-2
Vila, E Iglesias, JE Galy, J Castro,
A
Synthesis and characterization of a novel bismuth-molybdenum oxide
and
study of its ionic conducting behavior
SOLID STATE SCIENCES
Bi10Mo3O24.
The crystal data have been determined by ab
initio indexing of the powder pattern.
TREOR
2005-3
Bestaoui, N Xiang, OY Fredoueil, F
Bujoli, B Clearfield, A
Structural characterization of Cd-3(O3PC2H4CO2) (2). 2H(2)O
from in-house X-ray powder data and NMR
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 669-674.
poly[[bis(mu-2-carboxylatoethylphosphonato)cadmium]
dihydrate], Cd-3(O3PC2H4CO2)(2) . 2H(2)O,
structure determined from in-house powder data.
The structure was solved in both P2(1)/c and P2(1) space groups.
TREOR
2005-6
Burley, JC
Structure and intermolecular interactions of glipizide from laboratory
X-ray powder diffraction
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE, 61, 2005, 710-716.
The crystal structure of glipizide, used as a major treatment of type-2
diabetes, has been determined ab initio using variable-temperature
laboratory X-ray powder diffraction combined with a direct-space
Monte
Carlo/simulated annealing methodology. The strengths of
the
intermolecular interactions (van der Waals, pi-pi stacking,
hydrogen
bonding and steric interlock) were quantitatively estimated
using the
thermal expansion data, which were collected in the same
set of
experiments as those used to determine the structure.
TREOR, DICVOL
2005-7 ??
Rodriguez, A Sakiyama, H Masciocchi, N
Galli, S Galez, N
Lloret, F Colacio, E
Hexacyanocobaltate(III) anions as precursors of Co(II)-Ni(II)
cyano-bridged multidimensional assemblies: Hydrothermal
syntheses,
crystal and powder x-ray structures, and magnetic properties
INORGANIC CHEMISTRY 44, 2005, 8399-8406.
unconventional powder X-ray diffraction analyses
TREOR
2005-8
Bonhomme, F Alam, TM Celestian, AJ
Tallant, DR Boyle, TJ
Cherry, BR Tissot, RG Rodriguez,
MA Parise, JB Nyman, M
Tribasic lead maleate and lead maleate: Synthesis and structural and
spectroscopic characterizations
INORGANIC CHEMISTRY 44, 2005, 7394-7402.
[Pb4O3]C2H2(CO2)(2)(.)1/2H(2)O, solved ab initio from X-ray powder
diffraction data,
TREOR
2005-9
Barbier, J Penin, N Denoyer, A Cranswick,
LMD
BaBiBO4, a novel non-centrosymmetric borate oxide
SOLID STATE SCIENCES 7, 2005, 1055-1061.
BaBiBO4 or BaBi(BO3)O, Pna2(1)
crystal structure determined from
powder X-ray diffraction data and refined from powder
neutron
diffraction data
TREOR
2005-10
Kelm, K Mader, W
Synthesis and structural analysis of epsilon-Fe2O3
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 2383-2389
epsilon-Fe2O3 Pna2(1)
ab initio, X-ray diffraction data of the powder containing
small amounts of Al substituting Fe were refined by the
Rietveld
method.
TREOR
2005-11
Fukuda, K Fukushima, K
Crystal structure of hexagonal SrAl2O4 at 1073 K
OURNAL OF SOLID STATE CHEMISTRY 178, 2005, 2709-2714
SrAl2O4 at 1073 K - P63 , Z = 6
determined from
conventional X-ray powder diffraction data using direct methods,
refined by the Rietveld method. The structure was hexagonal
TREOR
2005-12
Bhuvanesh, NSP Reibenspies, JH Zhang, YG
Lee, PL
A novel strategy for ab initio structure determination using
micro-powder X-ray diffraction: structure solution and
refinement of
3-bromophenylboronic acid and tris(4-bromophenyl) boroxine
JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 632-638.
3-bromo-phenylboronic acid and
tris(4-bromophenyl) boroxine, were
recorded with microgram quantities of sample using a recently
developed
method employing nylon loops with
synchrotron radiation and an image-plate detector.
The structures of the two
compounds have been solved by ab initio methods using
real-space
techniques ( simulated annealing and/or parallel tempering)
followed by
Rietveld refinements with soft restraints on the bond
lengths of the
rigid bodies.
It is believed that this is the first time that powder X-ray
diffraction patterns using microgram samples have been
successfully
employed for the structure solution and refinement of
molecules with
reasonable complexity.
TREOR, DICVOL,
2005-13
Zhang, Y Liu, QL Li, JB Liang, JK
Luo, J Liu, FS Xiao, YG Rao, GH
Structures of the zeta and zeta ' phases in the Ag-Ga system
JOURNAL OF ALLOYS AND COMPOUNDS 399 (2005) 155-159.
zeta-phase P63/mmc and
zeta'-phase : Ag2Ga (real composition Ag2+xGa1-x, x = 0.16) P-6
determined by X-ray powder diffraction and refined by
Rietveld method.
TREOR
2005-14
Lefebvre, J Willart, JF Caron, V
Lefort, R Affouard, F Danede, F
Structure determination of the 1/1 alpha/beta mixed lactose by X-ray
powder diffraction
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 455-463.
mixed form of alpha/beta lactose
The X-ray powder diffraction pattern
was recorded at room temperature with a sensitive curved
detector (CPS
120). The structure was solved by real-space methods (
simulated
annealing) followed by Rietveld refinements with soft
constraints on
bond lengths and bond angles.
The width of the Bragg peaks is interpreted through a
microstructural approach in terms of isotropic strain
effects and
anisotropic size effects.
TREOR
2005-15
Zhang, QA Yang, WM Akiba, E
Synthesis and crystal structure of a new ternary compound Ca4Al3Mg
JOURNAL OF ALLOYS AND COMPOUNDS 398, 2005, 123-126.
Ca4Al3Mg Pbcm
The crystal structure was determined by X-ray powder diffraction.
TREOR
2005-16
Fukuda, K Moriyama, A Iwata, T
Crystal structure, phase transition and anisotropic thermal expansion
of barium zirconium diorthophosphate, BaZr(PO4)(2)
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 2144-2151.
BaZr(PO4)(2) at 298 K C2/m Z = 2
determined from
conventional X-ray powder diffraction data using direct
methods, and it
was further refined by the Rietveld method.
TREOR
2005-17
Tsirlin, AA Chernaya, VV Shpanchenko, RV
Antipov, EV Hadermann, J
Crystal structure and properties of the new complex vanadium oxide
K2SrV3O9
MATERIALS RESEARCH BULLETIN 40, 2005, 800-809.
K2SrV3O9 Pnma and Z = 4.
investigated by means of X-ray powder diffraction (XPD)
refined by Rietveld method using X-ray powder diffraction
data.
TREOR
2005-18
Salvado, MA Pertierra, P Bortun, AI
Trobajo, C Garcia, JR
New hydrothermal synthesis and structure of Th-2(PO4)(2)(HPO4)-H2O:
the
first structurally characterized thoriurn hydrogenphosphate
INORGANIC CHEMISTRY
Th-2(PO4)(2)(HPO4)-H2O P21, Z = 2
solved by powder X-ray diffraction data
TREOR
2005-19
Shin, N Kim, J Ahn, D Sohn, KS
A new strontium borophosphate, Sr6BP5O20, from synchrotron powder data
ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 61,
2005, 154-156.
Strontium borophosphate, Sr6BP5O20, was prepared by a solution
synthesis method. The crystal structure was solved ab
initio from
synchrotron powder data without preliminary knowledge
of the chemical
formula. The compound crystallizes in space group I (4)
over bar c2. Sr
atoms occupy sites coordinated by eight or nine O atoms,
and the
anionic layer consists of BO4 and PO4 tetrahedra. The
eightfold-coordinated Sr atom lies at a site with twofold
symmetry,
while one P atom and the B atom are located on special
positions of
site symmetry (4) over bar.
TREOR, DICVOL
2005-20
Stahl, K Balic-Zunic, T da Silva, F
Eriksen, KM Berg, RW Fehrmann, R
The crystal structure determinations and refinements of K2S2O7, KNaS2O7
and Na2S2O7 from X-ray powder and single crystal diffraction
data
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 1697-1704.
K2S2O7, C2/c and KNaS2O7
solved and/or refined from X-ray synchrotron powder diffraction data
TREOR
2005-21
Malpezzi, L Magnone, GA Masciocchi, N
Sironi, A
Single crystal and powder diffraction characterization of three
polymorphic forms of Acitretin
JOURNAL OF PHARMACEUTICAL SCIENCES 94, 2005, 1067-1078.
Polymorphs of Acitretin :
[all-trans-9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-2,4,6,8-nona
tetraenoic acid or
3-methoxy-2-methyl-17-nor-1,2,3,4-tetradehydroretinoic
acid],
three polymorphic modifications (hereafter, I, II, and III),
TREOR
X-ray powder diffraction methods (form II
and III) from conventional laboratory data only.
real space techniques (simulated annealing and whole-profile
pattern
matching) have been employed.
These results show that ab initio
structural studies from conventional laboratory X-ray
powder
diffraction (XRPD) data are fully providing the opportunity
to
investigate the structural aspects of moderately complex
substances
also in the absence of single crystals, disclosing the
crystal
chemistry of a few polymorphs of pharmaceutically relevant
species.
TREOR
2005-22
Bestaoui, N Bakhmutova-Albert, EV Rodriguez,
AV Llavona, R Clearfield, A
Ab-initio powder structure determination of
dichloro[1,2ethanediylbis(iminomethylene)bis(phosphonato)]trizinc
dihydrate
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY iss 5, 2005, 829-836.
dichloro[1,2-ethanediylbis(iminomethylene)bis(phosphonato)]trizinc
dihydrate, Zn3Cl2(HO3PCH2NHCH2CH2NHCH2PO3H)(2) .
2H(2)O
P2(1)/n, Z = 4.
The crystal structure was determined ab initio from its powder pattern
using
the programs EXPO and GSAS.
TREOR
2005-23
Fernandez-Carrasco, L Puertas, F Blanco-Varela,
MT Vazquez, T Rius, J
Synthesis and crystal structure solution of potassium dawsonite: An
intermediate compound in the alkaline hydrolysis of calcium
aluminate
cements
CEMENT AND CONCRETE RESEARCH 35, 2005, 641-646.
Potassium dawsonite KAI(CO3)(OH)2 Cmcm Z =
4.
has been solved by
direct methods from X-ray powder diffraction data and
refined with the
Rietveld method.
TREOR
2005-24
Ribas, X Sironi, A Masciocchi, N
Lopes, EB Almeida, M Veciana, J Rovira,
C
Structural, magnetic, and electrical characterization of new
polycrystalline phases of nickel- and platinum-doped
[(DT-TTF)n][Au(mnt)(2)] (n=1,2)
INORGANIC CHEMISTRY 44, 2005, 2358-2366.
determined using laboratory X-ray powder diffraction data.
TREOR
2005-25
Baies, R Caignaert, V Pralong, V
Raveau, B
Copper hydroxydiphosphate with a one-dimensional arrangement of copper
polyhedra: Cu-3[P2O6OH](2)
INORGANIC CHEMISTRY 44, 2005, 2376-2380.
Cu-3(P2O6OH)(2) P1
solved ab initio from X-ray powder diffraction data
TREOR
2005-26
Lu, J Wei, S Yu, WC Zhang, HB
Qian, YT
TStructure and luminescence of 2D dilute magnetic semiconductors:
Cd1-xMnxSe . L-0.5 (L = diamines)
CHEMISTRY OF MATERIALS 17, 2005, 1698-1703.
The two-dimensional (2D) dilute magnetic semiconductors
(Cd1-xMnxSeL0.5)-L-. (L = ethylenediamine, or en, and
1,6-hexanediamine, or hda, x = 0-0.8) were synthesized
in an autoclave
at 120 degrees C. Ab initio structure solution from X-ray
powder
diffraction reveals the host compound CdSe .
hda(0.5) (space
group, Pbca, a = 6.8852 angstrom, b = 6.7894 angstrom,
c = 27.4113
angstrom) is structurally analogous to CdSe .
en(0.5), except
for a subtle difference in alignment of aliphatic diamine
ligands-the
hda molecule deflects from the c axis and inclines toward
the b axis.
TREOR
2005-27
Bonhomme, F Larentzos, JP Alam, TM
Maginn, EJ Nyman, M
Synthesis, structural characterization, and molecular modeling of
dodecaniobate Keggin chain materials
INORGANIC CHEMISTRY 44, 2005, 1774-1785.
Four new isostructural one-dimensional dodecaniobate Keggin materials,
Na-12[Ti2O2][TNb1 2O40]-xH(2)O and Na-10[Nb2O2][TNb12O40]-xH(2)O
with T
= (Si or Ge), have been synthesized hydrothermally using
a
Lindqvist-ion salt, Na-7 [Nb6O19H]-15H(2)O, as the precursor.
Their
structure, consisting of chains of Keggin ions [TNb12O40](16-)
linked
by [Ti2O2](4+) or [Nb2O2](6+) bridges, was solved ab initio
from powder
diffraction data.
TREOR
2005-28
Gallo, E Caselli, A Ragaini, F Fantauzzi,
S Masclocchi, N Sironi, A Cenini, S
Structural determination of ruthenium-porphyrin complexes relevant
to
catalytic epoxidation of olefins
INORGANIC CHEMISTRY 44, 2005, 2039-2049
A reproducible synthesis of a competent epoxidation catalyst,
[Ru-VI(TPP)(0)(2)] (TPP = tetraphenylporphyrin dianion),
starting from
[Ru-II(TPP)(CO)L] (L = none or CH3OH), is described. The
molecular
structure of the complex was determined by using ab initio
X-ray powder
diffraction (XRPD) methods
TREOR
2005-29
Boldyreva, EV Ivashevskaya, SN Sowa, H
Ahsbahs, H Weber, HP
Effect of hydrostatic pressure on the gamma-polymorph of glycine -
1. A
polymorphic transition into a new delta-form
ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 50-57.
The results of a high-resolution powder diffraction study of the effect
of high hydrostatic pressure up to 8 GPa on the pure gamma-polymorph
of
glycine (P3(1)) are discussed. A phase transition with
a jumpwise
change of cell volume and cell parameters was observed.
The transition
starts at about 2.73 GPa and is still not complete even
at 7.85 GPa.
The crystal structure of the previously unknown high-pressure
polymorph
of glycine (delta-polymorph) could be solved and refined
in the space
group Pn.
TREOR
2005-30
Platteau, C Lefebvre, J Affouard, F
Willart, JF Derollez, P Mallet, F
Structure determination of the stable anhydrous phase of alpha-lactose
from X-ray powder diffraction
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 185-191.
The stable anhydrous form of alpha-lactose has been obtained by the
dehydration of alpha-lactose monohydrate in methanol.
An Xray powder
diffraction pattern was recorded at room temperature with
a laboratory
diffractometer equipped with an INEL curved sensitive
detector CPS120.
The starting structural model of this form was found by
a Monte-Carlo
simulated annealing method.
TREOR
2005-31
Barea, E Romero, MA Navarro, JAR
Salas, JM Masciocchi, N Galli, S Sironi,
A
Structure, spectroscopic properties, and reversible solid-to-solid
reactions of metal complexes of 5-nitro-pyrimidin-2-olate
INORGANIC CHEMISTRY 44, 2005, 1472-1481.
In searching for coordination polymers containing the highly polarized
5-nitro-pyrimidin-2-olate ligand (NP), a number of species
containing
3d transition metals have been prepared and characterized,
namely
Co(NP)(2)(H2O)(4), [Co(NP)(2)](n), Ni(NP)(2)(H2O)(4),
Ni(NP)(2)](x),
and [Zn(NP)(2)](n). Their structures have been determined
by X-ray
powder diffraction methods.
TREOR
2005-32
Ivashkevich, LS Lyakhov, AS Ivashkevich, DO
Degtyarik, MM Gaponik, PN
Synthesis and crystal structure of the
catena-poly[[bis(1-methyltetrazole-N-4)copper(II)]-di-mu-chloro]
complex CuCl2(C2H4N4)(2)
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY 50, 2005, 78-82
The X-ray diffraction study of the CuCl2(C2H4N4)(2) complex, where
C2H4N4 is 1-methyl-tetrazole, was carried out. The structure
was solved
ab initio using the X-ray powder diffraction data. The
complex
crystallizes in space group P2(1)/c, alpha = 11.2341(6)
Angstrom, b =
6.7272(3) Angstrom, c = 7.2149(3) Angstrom, 104.718(3)degrees,
V
527.36(4) Angstrom(3), Z = 2.
TREOR
2005-33
Ivashkevich, LS Lyakhov, AS Degtyarik, MM
Gaponik, PN
An X-ray powder diffraction study of
catena-poly[[bis(1-methyl-1H-tetrazole-kappa
N-4)copper(II)]-di-mu-bromo]
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, 61, 2005,
M394-M396.
The crystal structure of the polymeric title complex,
[CuBr2(C4H8N8)(2)](n), has been solved from X-ray powder
data and
refined with the Rietveld method using geometrical soft
restraints.
TREOR
2005-34
Chernaya, VV Mitiaev, AS Chizhov, PS
Dikarev, EV Shpanchenko, RV
Antipov, EV Korolenko, MV Fabritchnyi,
PB
Synthesis and investigation of Tin(II) pyrophosphate Sn2P2O7
CHEMISTRY OF MATERIALS 17, 2005, 284-290.
The crystal structure
of the high temperature alpha-Sn2P2O7 form was solved
using
high-temperature powder diffraction data collected at
773 K. The
structural motif of the high temperature form (monoclinic,
P2(1)/n, a =
7.1765(4) Angstrom, b = 9.2874(6) Angstrom, c = 5.2968(4)
Angstrom,
beta = 106.034(3)degrees, V = 339.30(5) Angstrom(3), Z
= 2) is closely
related to the room temperature modification.
TREOR
2005-35
Platteau, C Lefebvre, J Hemon, S
Baehtz, C Danede, F Prevost, D
Structure determination of forms I and II of phenobarbital from X-ray
powder diffraction
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 80-88.
From pure powders of forms I and II of phenobarbital, X-ray diffraction
patterns were recorded at room temperature. The starting
crystal
structural models were found by a Monte-Carlo simulated
annealing
method. The structures of the two forms were obtained
through Rietveld
refinements. Soft restraints were applied on bond lengths
and bond
angles, all H-atom positions were calculated. The cell
of form I is
monoclinic with the space group P2(1)/n, Z = 12, Z' =
3. Form II has a
triclinic cell, with the space group P (1) over bar, Z
= 6, Z' = 3. For
both forms, the crystal cohesion is achieved by networks
of N - H ... O
hydrogen bonds along [101]. The broadening of the Bragg
peak profiles
is interpreted in terms of isotropic strain effects and
anisotropic
size effects.
TREOR
2005-36
Derollez, P Correia, NT Danede, F
Capet, F Affouard, F Lefebvre, J Descamps,
M
Ab initio structure determination of the high-temperature phase of
anhydrous caffeine by X-ray powder diffraction
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 329-334.
The high-temperature phase I of anhydrous caffeine was obtained by
heating and annealing the purified commercial form II
at 450 K. This
phase I can be maintained at low temperature in a metastable
state. A
powder X-ray diffraction pattern was recorded at 278 K
with a
laboratory diffractometer equipped with an INEL curved
position-sensitive detector CPS120. Phase I is dynamically
orientationally disordered (the so-called plastic phase).
The Rietveld
refinements were achieved with rigid-body constraints.
It was assumed
that on each site, a molecule can adopt three preferential
orientations
with equal occupation probability. Under a deep undercooling
of phase
I, below 250 K, the metastable state enters in a glassy
crystal state.
N-TREOR
2005-37
Jorda, JL Prokic, S McCusker, LB
Baerlocher, C Xue, CF Jong, JX
Synthesis and structure analysis of the potassium calcium silicate
CAS-1. Application of a texture approach to structure
solution using
data collected in transmission mode
COMPTES RENDUS CHIMIE 8, 2005, 331-339.
The crystal structure of the potassium calcium silicate material, CAS-1
(|(Ca4K4(H2O)(8))|[Si16O38]), has
been determined from
synchrotron powder diffraction data collected on a textured
polycrystalline sample. It was not possible to solve the
structure
directly from normal high-resolution powder diffraction
data, so the
newly developed texture approach to structure solution
using data
collected in transmission mode was applied. Data analysis
was performed
using the computer program Expol, which has been developed
to handle
the large amount of data generated in transmission mode.
The structure
could then be solved by direct methods, and Rietveld refinement
(using
data collected on an untextured sample) converged with
R-F = 0.062 and
R-wp = 0.175 (R-exp = 0.097). This structure is the first
novel
structure to be solved using the texture method in this
configuration.
As suggested by Si-29 MAS NMR results (1 Q(4) and 3 Q(3)
signals, all
of equal intensity), CAS-1 (C2, a = 24.158 &ANGS;,
b = 7.016 &ANGS;, c
= 6.482 &ANGS;, β = 95.19°) proved
to be a layer silicate. The
structure can be described as a series of silicate double
layers
connected via chains of edge-sharing CaO5(H2O) octahedra.
There is a
two-dimensional eight-ring channel system within the silicate
layer,
and K+ ions, which balance the charge, are located in
the eight-rings
of the two 4.8(2) nets that form the double layer. One
water molecule
is located in the channel system and another bridges between
K+ and
Ca2+ ions. The structure is related to that of the natural
mineral
rhodesite.
2005-38 ??
Anillo, A Altomare, A Moliterni, AGG
Bauer, EM Bellitto, C
Colapietro, M Portalone, G Righini,
G
Hydrothermal synthesis, structural characterization and magnetic
studies of the new pillared microporous ammonium Fe(III)
carboxyethylphosphonate: [NH4][Fe-2(OH){O3P(CH2)(2)CO2}(2)]
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 306-313.
The preparation by hydrothermal reaction and the crystal structure
of
the iron(III) carboxyethylphosphonate of formula
[NH4][Fe-2(OH){O3P(CH2)(2)CO2}(2)] is reported. The green-yellow
compound crystallizes in the monoclinic system, space
group Pc(n.7),
with the following unit-cell parameters: a = 7.193(3)
A, b = 9.776(3)
A, c = 10.17(4) A and beta = 94.3(2)degrees. It shows
a typical layered
hybrid organic-inorganic structure featuring an alternation
of organic
and inorganic layers along the a-axis of the unit cell.
The
bifunctional ligand [O3P(CH2)(2)CO2](3-) is deprotonated
and acts as a
linker between adjacent inorganic layers, to form pillars
along the
a-axis. The inorganic layers are made up of dinuclear
Fe(III) units,
formed by coordination of the metal ions with the oxygen
atoms
originating from the [O3P-](2-) end of the carboxyethylphosphonate
molecules, the oxygen atoms of the [-CO2](-) end group
of a ligand
belonging to the adjacent layer and the oxygen atom of
the bridged OH
group. Each Fe(III) ion is six-coordinated in a very distorted
octahedral environment. Within the dimer the Fe-Fe separation
is found
to be 3.5 A, and the angle inside the [Fe(1)-O(11)-Fe(2)]
dimers is
similar to124degrees. The resulting 3D framework contains
micropores
delimited by four adjacent dimers in the (bc) planes of
the unit cell.
These holes develop along the a-direction as tunnel-like
pores and
[NH4](+) cations are located there. The presence of the
p-hydroxo-bridged [Fe(1)-O(11)-Fe(2)] dimers in the lattice
is also
responsible for the magnetic behavior of the compound
at low
temperatures. The compound contains Fe3+ ions in the high-spin
state
and the two Fe(III) ions are antiferromagnetic coupled.
The J/k value
of -16.3 K is similar to those found for other mu-hydroxo-bridged
Fe(III) dimeric systems having the same geometry.
N-TREOR
2005-39
Muhle, C Karpov, A Jansen, M
Crystal structure elucidation of anhydrous Rb-2[Pt(CN)(4)] from X-ray
powder diffraction data
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES
60, 2005, 1269-1272.
The title compound has been synthesized by metathesis of
Ba[Pt(CN)(4)].4 H2O with Rb2SO4, in aqueous solution.
Its crystal
structure was solved from X-ray powder diffraction data
using the
simulated-annealing approach, and refined by Rietveld's
method. The
compound crystallizes in space group Imma, a = 11.1432(2),
b =
7.4382(1), c = 11.1896(2) angstrom, V = 927.45(3) angstrom(3),
Z = 4,
R-P = 0.0402, R-W = 0.0247 (N-hkl = 173). Square-planar
tetracyanoplatinate groups stack in an unprecedented eclipsed
conformation, forming one-dimensional linear chains of
Pt-atoms with
Pt-Pt separations of 3.719 angstrom. Rb-2[Pt(CN)(4)] was
characterized
by differential thermal analysis, thermo-gravimetry and
infrared
spectroscopy.
DICVOL
2005-40
Ramirez-Cardona, M Ventola, L Calvet, T
Cuevas-Diarte, MA
Rius, J Amigo, JM Reventos, MM
Crystal structure determination of 1-pentanol from low-temperature
powder diffraction data by Patterson search methods
POWDER DIFFRACTION 20, 2005, 311-315.
In the course of our research on normal alkanols, the crystal structure
of 1-pentanol has been solved by applying Patterson-search
methods to
laboratory powder X-ray diffraction data recorded on a
curved
position-sensitive detector (CPS120) at 183 K. The crystal
structure
was refined with the rigid-body Rietveld least-squares
method. The cell
is monoclinic, space group P2(1)/c, Z=4, and the cell
parameters are a
= 15.592(9) angstrom, b=4.349(1) angstrom, c=9.157(1)
angstrom, beta =
104.7(7)degrees, V=600.6(3) angstrom(3). There is one
molecule in the
asymmetric unit with the O-H bond in gauche conformation
with respect
to the alkyl skeleton. Packing is defined by the hydrogen
bonds linking
the 1-pentanol molecules along zigzag chains parallel
to b.
DICVOL
2005-41
Pan, ZG Cheung, EY Harris, KDM Constable,
EC Housecroft, CE
Structural properties of methoxy derivatives of benzyl bromide,
determined from powder X-ray diffraction data
POWDER DIFFRACTION 20, 2005, 345-352.
Structure determination of 3,5-dimethoxybenzyl bromide and
3,4,5-trimethoxybenzyl bromide has been carried out from
laboratory
powder X-ray diffraction data using the direct-space Genetic
Algorithm
technique for structure solution followed by Rietveld
refinement. These
two compounds are of interest for their potential use
as building
blocks for the synthesis of dendritic materials. Although
the two
molecules differ only in the presence/absence of the methoxy
group at
the 4-position of the aromatic ring, the structural properties
of the
two materials are significantly different. (C) 2005 International
Centre for Diffraction Data.
DICVOL
2005-42
Grzechnik, A Dmitriev, V Weber, HP
Dilithium zirconium hexafluoride Li2ZrF6 at high pressures: A new
monoclinic phase
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 66, 2005, 1769-1774.
Dilithium zirconium hexafluoride, Li2ZrF6 (P31m, Z = 1), is studied
at
high pressures using synchrotron angle-dispersive X-ray
powder
diffraction in a diamond anvil cell at room temperature.
At atmospheric
conditions, it has a structure with all the cations octahedrally
coordinated to fluorine atoms. Above 10 GPa it transforms
reversibly to
a new polyrnorph (C2/c, Z = 4), in which the coordination
polyhedron of
the Zr atorns is a distorted square antiprism, while the
Li atoms are
in the octahedral coordination. The LiF6 octahedra form
layers parallel
to (100) that are connected by zig-zag chains of the edge-sharing
Zr
polyhedra running in the [001] direction. The relative
change in
volumes per one formula unit for both polymorphs is 6%
at 11.8 GPa. The
relations to other A(2)BX(6)-type structures are discussed.
DICVOL
2005-43
Vila, E Iglesias, JE Galy, J Castro,
A
Synthesis and characterization of a novel bismuth-molybdenum oxide
and
study of its ionic conducting behavior
SOLID STATE SCIENCES 7, 2005, 1369-1376.
A wet chemistry method applied to the synthesis of bismuth-molybdenum
oxides leads to the low temperature synthesis of a new
phase with
composition Bi10Mo3O24. The crystal data have been determined
by ab
initio indexing of the powder pattern. It crystallizes
in the
monoclinic system, with unit-cell parameters a = 23.7235(4),
b =
5.64720(8), c = 8.6798(1) angstrom, beta = 95.879(1)degrees
and V =
1156.73 angstrom(3). A preliminary heavy-atom skeleton
related to the
fluorite structure allowed us to postulate a layer structure
with
composition [Bi10O12](n) [MoO4](3n): This compound has
been processed
by spark plasma sintering as a ceramic material, exhibiting
good ionic
conductor properties in the whole temperature range of
stability.
DICVOL
2005-44
Blagden, N Davey, R Dent, G Song,
M David, WIF
Pulham, CR Shankland, K
Woehler and Liebig revisited: A small molecule reveals its secrets
-
The crystal structure of the unstable polymorph of benzamide
solved
after 173 years
CRYSTAL GROWTH & DESIGN 5, 2005, 2218-2224.
In this work, we revisit the question of the metastable crystal form
of
benzamide. This was first identified in 1832 by Liebig
and Woehler, but
its structure has never been determined. It is shown how
a combination
of microscopic, spectroscopic, and diffraction techniques
have been
used to solve, finally, the structure of this highly metastable
Form II
of benzamide. The combination of morphology, disorder,
and nucleation
under highly labile conditions lead to some speculation
as to the
origins of such an unstable polymorph.
DICVOL
2005-45
David, WIF Shankland, K Pulham, CR
Blagden, N Davey, RJ Song, M
Polymorphism in benzamide
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 44, 2005, 7032-7035.
DICVOL
2005-46
Surble, S Serre, C Millange, F Pelle,
F Ferey, G
Synthesis, characterisation and properties of a new three-dimensional
Yttrium-Europium coordination polymer
SOLID STATE SCIENCES 7, 2005, 1074-1082.
A new three-dimensional europium-doped Yttrium(III) tricarboxylate,
MIL-92LT(1) or Y1-xEux (H2O)(2) {C6H3-(CO2)(3)} (x similar
to 0.03)
(LT: Low Temperature) has been synthesised hydrothermally.
Its
three-dimensional structure, determined using X-ray powder
diffraction
data, is built-up from isolated eight coordinated Ln(III)
monocapped
square antiprisms (Ln = Y, Eu) linked through carboxylate
moieties. Its
thermal behaviour, investigated using TGA and X-ray
thermodiffractometry indicates that dehydration is irreversible
giving
the solid MIL-92(HT) or Y1-xEux {C6H3-(CO2)(3)} (x similar
to 0.03)
(HT: High Temperature). It induces a change in the connection
mode of
the carboxylate and a decrease in the coordination number
of the
rare-earth leading to an unusual octahedral environment
for the
rare-earth cation. After a structural analysis of the
reconstructive
phase transition, the optical properties of these solids
have been
investigated and show that dehydration leads to a strong
increase in
the optical output. Crystal data for MIL-92(LT): monoclinic
space group
C2/c (n degrees 15) with a = 16.428 (1) angstrom, b =
6.071 (1)
angstrom, c = 20.404(l) angstrom, beta = 95.31(3)degrees
and Z = 2.
Crystal data for MIL-92(HT): monoclinic space group C2/c
(n degrees 15)
with a = 17.390(1) angstrom, b = 5.521 (1) angstrom, c
= 19.487(1)
angstrom, beta = 105.35 (2)degrees and Z = 2.
DICVOL
2005-47
Harper, JK Barich, DH Heider, EM
Grant, DM Franke, RR
Johnson, JH Zhang, YG Lee, PL
Von Dreele, RB Scott, B
Williams, D Ansell, GB
A combined solid-state NMR and X-ray powder diffraction study of a
stable polymorph of paclitaxel
CRYSTAL GROWTH & DESIGN 5, 2005, 1737-1742.
Solid-state NMR (SSNMR) and X-ray powder diffraction (XRPD) allow a
study of a novel and stable polymorph of paclitaxel (Taxol)
with two
molecules per asymmetric unit (Z') in the P2(1)2(1)2(1)
space group.
The asymmetric unit volume is 2167 angstrom(3), about
four times larger
than that previously characterized in combined XRPD/ SSNMR
studies. The
method, employing SSNMR constraints, allows the XRPD Rietveld
analysis
to establish many of the lattice details that otherwise
would be
unavailable. NMR structural constraints are provided by
isotropic
shifts and three-dimensional (3D) chemical shift tensors
(CST), which
are determined by ab initio quantum mechanical calculations.
CST data
give highly sensitive information on short-range structural
features
such as intra-atomic distances (particularly for proton
positions that
are undetermined with XRPD methods) and short-range valence
angles that
exhibit relatively poor sensitivity in reasonably large
microcrystalline powders. Conversely, space group symmetry,
unit cell
volumes, long-range cell dimensions, and dihedral angles
of extended
chains are estimated with XRPD measurements. Corroboration
of many
structural parameters by combined quantum mechanical,
SSNMR, and XRPD
results indicate the efficacy of these combined approaches
in
relatively sizable microcrystalline powders. The population
of the
asymmetric unit, Z' = 2 is clearly observed even in the
one-dimensional
isotropic C-13 spectra, which also confirmed the stability
of the
polymorph over a three-year period. This structural determination
depends specifically on the agreement between previous
SSNMR CSTs and
single crystal results for baccatin, the rigid part of
paclitaxel.
Hence, CST data provide a reasonable initial model for
the early
iterative steps of a Rietveld analysis of XRPD data for
a new polymorph
of Taxol.
DICVOL
2005-48
Wu, L Chen, XL Li, H He, M
Xu, YP Li, XZ
Structure determination and relative properties of novel cubic borates
MM '(4)(BO3)(3) (M = Li, M ' = Sr; M = Na, M ' = Sr, Ba)
INORGANIC CHEMISTRY 44, 2005, 6409-6414.
A series of novel borates, MM'(4)(BO3)(3) (M = Li, M' = Sr; M = Na,
M'
= Sir, Ba), have been successfully synthesized by standard
solid-state
reaction. The crystal structures have been determined
from powder X-ray
diffraction data. They crystallize in the cubic space
group laid with
large lattice parameters: a = 14.95066(5) angstrom for
LiSr4(BO3)(3), a
= 15.14629(6) angstrom for NaSr4(BO3)(3), and a = 15.80719(8)
angstrom
for NaBa4(BO3)(3). The structure was built up from 64
small cubic
grids, in which the M' atoms took up the corner angle
and the BO3
triangles or MO6 cubic octahedra filled in the interspaces.
The
isolated [BO3](3-) anionic groups are perpendicular to
each other,
distributed along three (100) directions. The anisotropic
polarizations
were counteracting, forming an isotropic crystal. Sr and
Ba atoms were
found to be completely soluble in the solid solution
NaSr4-xBax(BO3)(3)(0 <= x <= 4). The photoluminescence
of samples doped
with the ions Eu2+ and Eu3+ was studied, and effective
yellow and red
emission was detected, respectively, The results are consistent
with
the crystallographic study. The! DTA and TGA curves of
them show that
they are chemically stable and congruent melting compounds.
DICVOL
2005-49
Florence, A Johnston, A Fernandes, P
Shankland, K
Stevens, HNE Osmundsen, S Mullen,
AB
Powder study of hydrochlorothiazide form II
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61, 2005,
O2798-O2800.
The crystal structure of hydrochlorothiazide form II, C7H8ClN3O4S2,
was
solved by simulated annealing from laboratory X-ray powder
diffraction
data collected at room temperature to 1.76 angstrom resolution.
Subsequent Rietveld refinement yielded an R-wp of 0.0376
to 1.49
angstrom resolution. The molecules crystallize in the
space group
P2(1)/c with one molecule in the asymmetric unit. The
structure is
stabilized by three N-H (. . .) N and one N-H (. . .)
O hydrogen-bonded
intermolecular interaction.
DICVOL
2005-50
Florence, AJ Johnston, A Shankland, K
Powder study of hydrochlorothiazide-methyl acetate (1/1)
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61, 2005,
O2974-O2977.
A polycrystalline sample of the title compound,
C(7)H(8)ClN(3)O(4)S(2) . C3H6O2, was produced during
an
automated parallel crystallization search on hydrochlorothiazide
(HCT).
The crystal structure was solved by simulated annealing
from laboratory
X-ray powder diffraction data collected at room temperature
to 1.75
angstrom resolution. Subsequent Rietveld refinement yielded
an R-wp
value of 0.0182 to 1.54 angstrom resolution. The compound
crystallizes
with one molecule of HCT and one of methyl acetate in
the asymmetric
unit and displays an extensive hydrogen-bonding network.
DICVOL
2005-51
Banerjee, S Mukherjee, AK Banerjee, I
De, RL Neumann, MA Louer, D
Synthesis, spectroscopic studies and ab-initio structure determination
from X-ray powder diffraction of
bis-(N-3-acetophenylsalicylaidiminato)copper(II)
CRYSTAL RESEARCH AND TECHNOLOGY 40, 2005, 815-821.
The synthesis, spectroscopic studies and crystal structure
determination from X-ray powder diffraction have been
carried out for
bis-(N-3-acetophenylsalicylaldiminato)copper(II). The
structure is
triclinic, space group P (l) over bar with unit cell dimensions
a=11.817(1)angstrom, b=12.087(1)angstrom, c=9.210(1)A,
alpha=102.62(1)degrees, beta=111.16(1)degrees, gamma=86.15(1)degrees,
V=1197.0(2)angstrom(3), Z=2. The structure has been solved
by Monte
Carlo simulated annealing approach and refined by GSAS
package. The
final Rp value was 8.68%. The coordination geometry around
the copper
atom in the complex is intermediate between square-planar
and
tetrahedral with two salicylaldimine ligands in trans
arrangement.
Intermolecular C-(HO)-O-.... hydrogen bonds between molecules
related
by translation generate infinite chains along [010] direction.
The
molecular chains are linked via additional C-(HO)-O-....
hydrogen bonds
to form a three-dimensional supramolecular network.
DICVOL
2005-52
Zhang, LM Schneider, J Luck, R
Phase transformations and phase stability of the AlCuFe alloys with
low-Fe content
INTERMETALLICS 13, 2005, 1195-1206.
Phase transformation and microstructure of the AlCuFe alloys of the
approximate compositional range of 20-50 at.% Cu and 1-10
Fe at.% have
been investigated for annealed samples by means of differential
thermal
analysis, magneto-thermal analysis, scanning electron
microscopy,
electron probe analysis and powder X-ray diffraction.
Representative
phase transformations categorized as polymorphic, discontinuous
precipitation, quasi-binary eutectoid, and ternary transition
reaction
(U-type) phase transformation are presented. These phase
transformations are found to have a common feature, which
is
characterized by a dissolution of a primitive CsCl-type
cubic phase and
a formation of a face-centered orthorhombic phase. The
crystal
structures of the cubic and orthorhombic phases are determined
from the
powder diffraction data using routines for indexing DICVOL,
for
intensity extraction and ab initio structure determination
EXPO and for
Rietveld refinement FULPROF. A face-centered orthorhombic
cell (a =
8.1530(3), b = 14.1370(4), c = 10.0736(4), Vol = 1161.0(7),
Z = 4, at
room temperature) with a starting structural model of,zeta-Al3Cu4
(space group Fmm2, Z=4) approximates the observed pattern
of powder
sample quenched from 620 degrees C fairly well. Refined
orthorhombic
cell dimensions are obtained by in situ high-temperature
X-ray
diffraction at 463, 553 and 636 degrees C. These phase
transformations
are sensitive to the heat treatment and the alloy composition.
They can
be suppressed at moderate cooling rates. The metastable
structures for
both slowly cooled and as-cast alloys are found to contain
the cubic
phase replacing the equilibrium orthorhombic phase.
DICVOL, EXPO, FULLPROF
2005-53
Littner, A Francois, M Tobola, J
Elkaim, E Malaman, B Vilasi, M
Ab-initio crystal structure of Mo4+xRu9-xSi5 (0 <= x <= 1) by
synchrotron powder diffraction and electronic properties
calculation
(KKR method)
INTERMETALLICS 13, 2005, 1048-1055
The crystal structure of the new phase Mo26Ru47Si27 (beta phase)
discovered during the study of the Mo-Ru-Si phase diagram
performed in
the aim of finding materials for high temperature applications,
was
determined by ab-initio methods from powder synchrotron
diffraction
data. Distribution of Ru and Mo atoms in the structure
is specified by
total energy electronic structure calculations using
Korringa-Kohn-Rostoker method. The compound crystallizes
in P4/mmm
space group with a=9.2164(1) angstrom, c=2.88721(1), angstrom,
D-x =
9.69(1) g/cm(3). The structure has been refined by the
Rietveld method
down to R-p = 1.1%, R-B = 12.0%, R-F = 8.7% for 6814 observed
data and
271 independent reflections. The structure consists of
four distorted
cubes 'Mo4Si4' centered by Ru atoms, sharing edges in
the (a,b) planes
to form cross-like units linked each others by the lateral
faces of the
branches in the (a,b) planes and stacked by faces along
the c
direction. The center of the crosses is occupied by Mo
or Ru atoms
(disorder 1d site) in an octahedral coordination. The
spacing between
the connected crosses is filled by four others distorted
cubic units
'Mo4Si4' centered themselves by Ru atoms.
The composition of the beta phase, determined by microprobe
analysis,
presents an homogeneity domain, which can be expressed
by the unit
formula Mo4+xRu9-xSi5 (0 <= x <= 1) compatible with
a partial or fully
occupation by Mo or Ru of the Wyckoff position Id of the
structure.
Electronic properties of ordered and disordered models
of Mo4+xRu9-xSi5
are also discussed.
DICVOL
2005-54 ??
Rousse, G Klotz, S Saitta, AM Rodriguez-Carvajal,
J
McMahon, MI Couzinet, B Mezouar,
M
Structure of the intermediate phase of PbTe at high pressure
PHYSICAL REVIEW B 71, 2005, 224116
The evolution of PbTe with pressure has been reexamined using
synchrotron x-ray diffraction. The phase transition at
6 GPa is not to
the GeS (B16) or TII (B33) type structures, as previously
reported, but
to an orthorhombic Pnma structure, with cell parameters
a=8.157(1),
b=4.492(1), and c=6.294(1)A at 6.7 GPa. This structure
corresponds to a
distortion of the low-pressure NaCl structure with a coordination
intermediate between the sixfold B1 (NaCl) and the eightfold
B2 (CsCl)
structure. We discuss the stability of this new structure
with respect
to other proposed phases using numerical methods. These
results may
modify the admitted paths of phase transitions between
the B1 and B2
structures.
DICVOL
2005-55
Loiseau, T Muguerra, H Haouas, M
Taulelle, F Ferey, G
Hydrothermal synthesis and structural characterization of a gallium
pyromellitate Ga(OH)(btec) . 0.5H(2)O, with infinite
Ga-(mu(2)-OH)Ga chains (MIL-61)
SOLID STATE SCIENCES 7, 2005, 603-609
A new gallium carboxylate Ga(OH)(btec) . 0.5H(2)O (MIL-61) was
synthesized under mild hydrothermal conditions (200 degrees
C, 24
hours) in the presence of 1,2,4,5-benzenetetracarboxylic
(btec) acid
and water. The crystal structure, characterized by means
of Rietveld
refinement of powder XRD data, consists of trans chains
of GaO4(OH)(2)
octahedra, connected to each other through a mu(2)-OH
group. The
three-dimensional framework is built up from these chains
linked
together via the organic molecules so delimiting the cavities
where the
water molecules are encapsulated. Analysis by solid state
NMR (1 H and
C-13) has confirmed the presence within the structure
of both water
molecules and carboxylate moieties partially deprotonated.
The
structure of Ga(OH)(btec) . 0.5H(2)O corresponds
to that of
MIL-61 obtained with vanadium replacing gallium.
Crystal data for Ga-4(OH)(4)((HO2C)(2)-C6H4-(CO2)(2))(4)
.
2H(2)O: a = 14.8325(10) angstrom, b = 6.7792(10) angstrom,
c =
10.6726(10) angstrom, V 1073.2(2) angstrom(3), Prima (n
degrees 62).
DICVOL
2005-56
van der Lee, A Richez, P Tapiero, C
Crystal structure of nitarsone determined from synchrotron X-ray powder
diffraction data
JOURNAL OF MOLECULAR STRUCTURE 743, 2005, 223-228.
The crystal structure of nitarsone, 4-nitrophenylarsonic acid, a
substitute for nifursol and dimetridazole in the prevention
and
treatment of turkey histomoniasis desease, has been determined
from
synchrotron X-ray powder diffraction data. Nitarsone crystallizes
in
the monoclinic space group P2(1)/n with unit cell parameters
a =
7.46413(5), b = 25.68543(17), c = 4.657388(32) &ANGS;,
β =
105.4670(5)&DEG;. The structure was solved using simulated
annealing
techniques by treating the molecule as a rigid body for
which the
configuration resulting from an energy minimization was
used in
slightly adapted form, Structure refinement treated the
NO2 and the
AsO(OH)(2) groups as free groups, leading to final confidence
factors
R-p = 0.059 and R-wp = 0.071. The crystal structure contains
4
molecules per unit cell that are hydrogen bonded to form
infinite
chains of dimers running along the c-axis. Nitarsone's
low toxicity
when compared with inorganic sources of arsenic is explained
by the
existence of a partial double C-As bond (1.866(5) &ANGS;)
which confers
greater stability so that under physiological conditions
nitarsone is
not converted to mineral-like As V or III.
DICVOL
2005-57
Guo, F Harris, KDM
Structural understanding of a molecular material that is accessed only
by a solid-state desolvation process: The scope of modern
powder X-ray
diffraction techniques
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 7314-7315.
HEMIMELLITIC ACID DIHYDRATE; GENETIC ALGORITHM
DICVOL
2005-58
Papoular, RJ Allouchi, H Chagnes, A
Dzyabchenko, A Carre, B
Lemordant, D Agafonov, V
X-ray powder diffraction structure determination of gamma-butyrolactone
at 180 K: phase-problem solution from the lattice energy
minimization
with two independent molecules
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 312-320.
The crystal structure of the solid phase of the dipolar aprotic solvent
γ-butyrolactone (BL1), C4H6O2, has been solved
using the
atom-atom potential method and Rietveld-refined against
powder
diffraction data collected at T = 180 K with a curved
position-sensitive detector (INEL CPS120) using Debye-Scherrer
diffraction geometry with monochromatic X-rays. It was
first deduced
from the X-ray experiment that the lattice parameters
are a = 10.1282
(4), b = 10.2303 (5), c = 8.3133 (4) &ANGS;, β
= 93.291 (2)&DEG;
and that the space group is P2(1)/a, with Z = 8 and two
independent
molecules in the asymmetric unit. The structure was then
solved by
global energy minimization of the crystal-lattice atom-atom
potentials.
The subsequent GSAS-based Rietveld refinement converged
to the final
crystal-structure model indicator R-F2 = 0.0684, profile
factors R-p =
0.0517 and R-wp = 0.0694, and a reduced χ(2) =
1.671. After further
cycles of heating and cooling, a powder diffraction pattern
markedly
different from the first pattern was obtained, again at
T = 180 K,
which we tentatively assign to a second polymorph (BL2).
All the
observed diffraction peaks are well indexed by a triclinic
unit cell
essentially featuring a doubling of the a axis. An excellent
Le Bail
fit is obtained, for which R-p = 0.0312 and R-wp = 0.0511.
DICVOL
2005-59
Loiseau, T Mellot-Draznieks, C Muguerra, H
Ferey, G
Haouas, M Taulelle, F
Hydrothermal synthesis and crystal structure of a new three-dimensional
aluminum-organic framework MIL-69 with 2,6-naphthalenedicarboxylate
(ndc), Al(OH)(ndc) . H2O
COMPTES RENDUS CHIMIE 8, 2005, 765-772.
A new three-dimensional aluminum-organic framework, MIL-69 or
Al(OH)(O2C-C10H6-CO2)(H2O)-H-., has been hydrothermally
synthesized at
210 &DEG; C for 16 h, by using 2,6-naphthalenedicarboxylic
acid as a
rigid ligand. The model for the crystal structure of MIL-69
was
determined by means of lattice energy minimizations and
further refined
against the powder XRD data using the Rietveld refinement
method. The
crystal structure consists of infinite chains of AlO4(OH)(2)
octahedra
corner-linked through the μ(2)-hydroxyl groups
and connected by the
2,6-naphthalenedicarboxylate moieties. It results in the
formation of
flat channels parallel to the chains of aluminum octahedra,
running
along the c axis. A water molecule is trapped nearby the
center of the
tunnels and mainly interacts via hydrogen bonds with the
hydroxyl
groups and the oxygen atoms of the carboxylates. Although
the
three-dimensional aluminum-organic framework is stable
up to 450 &DEG;
C, the tunnels still remain shrunk upon removal of water
molecule,
because of the occurrence 7r-n interactions between the
naphthalene
groups. The MIL-69 phase was characterized by solid state
NMR
MAS(27)Al, H-1 and C-13{H-1-decoupled}, which is consistent
with the
crystal structure description. Crystal data. - MIL-69,
Al(OH)(O2C-C10H6-CO2)(H2O)-H-.: Mr = 267.11 g mol(-1),
monoclinic,
space group C2/c (no. 15), a = 24.598(2) &ANGS;, b
= 7.5305(6) &ANGS;,
c = 6.5472(5) &ANGS;, β = 106.863(8)&DEG;,
V = 1160.6(2)
&ANGS;(3), Z = 4.
DICVOL
2005-60
Fernandes, P Florence, A Shankland, K
David, WIF
Powder diffraction study of 1,2 : 3,4-dibenzanthracene
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61, 2005,O1483-O1485.
The crystal structure of 1,2:3,4-dibenzanthracene, C22H14, was solved
by simulated annealing from laboratory X-ray powder diffraction
data
collected at room temperature to 1.8 &ANGS; resolution.
Subsequent
Rietveld refinement yielded an R-wp value of 0.036. The
molecules
crystallize in space group P2(1) with two independent
molecules in the
asymmetric unit which pack in a stacked arrangement along
the b axis.
DICVOL
2005-61
Lewis, GR Steele, G McBride, L Florence,
AJ Kennedy, AR
Shankland, N David, WIF Shankland,
K Teat, SJ
Hydrophobic vs. hydrophilic: Ionic competition in remacemide salt
structures
CRYSTAL GROWTH & DESIGN 5, 2005, 427-438.
Remacemide [2-aniino-N-(1-methyl-1,2-diphenylethyl)-acetamide] was
developed as a potential antagonist for epilepsy, Parkinsonism,
and
Huntington's disease. This paper investigates hydrophilic
and
hydrophobic intermolecular interactions that occur within
the series of
crystal structures comprising remacemide 1 and six of
its salts [2 =
chloride; 3 = nitrate; 4 = acetate (C2H3O2-); 5 = hydrogenfumarate
(C4H3O4-); 6 = naphthalene-2-sulfonate (napsilate, C10H7O3S-);
7 =
1-hydroxynaphthalene-2-carboxylate (xinafoate, C11H7O3-)].
The
hydrophilic interactions are described through graph set
analyses of
the hydrogen bond motifs and networks. The lattice of
1 comprises
unidirectional, one-dimensional chains of molecules parallel
to the
c-axis. In 2, the cation-anion hydrogen bonding imposes
a well-defined
hydrophilic stratum structure on the lattice. As the cation
itself is
amphiphilic, a natural consequence of this is the creation
of
two-dimensional stacked layers with alternating hydrophilic
and
hydrophobic character (lattice bilayers). This tendency
to form
bilayers within the lattice is also observed in structures
3-5 (polar
anions) and structures 6-7 (amphiphilic anions). Relatively
few
well-directed intermolecular interactions are observed
between aromatic
rings, either in 1 or in the hydrophobic layers of 2-7.
Therefore, it
is concluded that it is the hydrophilic hydrogen bond
interactions that
dominate the crystal packing and drive the segregation
into lattice
bilayers in the salt crystal structures.
DICVOL
2005-62
Bhuvanesh, NSP Reibenspies, JH Golden, ML
Darensbourg, MY
Zhang, YG Lee, PL
The vapochromic behavior, desulfoxidation and structural
characterization of the SO2 adducts of Ni(BME-DACH) from
powder data
SYNTHESIS AND REACTIVITY IN INORGANIC METAL-ORGANIC AND NANO-METAL
CHEMISTRY 35, 2005, 11-17.
Ab-initio structure determination of Ni(BME-DACH). SO2 has been carried
out by a combination of real space methods and Rietveld
analysis from
powder X-ray diffraction patterns obtained from microgram
quantities of
the compound mounted on a nylon loop (space group. P2(1)/c,
a =
8.871(1), b = 14.480(1), c = 10.576(1) angstrom, beta
=
95.98(1)degrees. The structure of Ni(BME-DACH). SO2 shows
that
Ni(BME-DACH) complex remains intact and is related to
the structure of
Ni(BME-DACH).2SO(2), providing a platform for SO2 binding.
We have also
followed the desulfoxidation of the 2SO(2) adduct by in-situ
micro-powder X-ray diffraction and, based on the results,
a mechanism
is proposed.
DICVOL
2005-63
Janaswamy, S Chandrasekaran, R
Polysaccharide structures from powder diffraction data: molecular
models of arabinan
CARBOHYDRATE RESEARCH 340, 2005, 835-839.
X-ray intensity data from a polycrystalline sample of debranched
arabinan, [-> 5)-alpha-L-Ara(f)-(1 ->](n), have been obtained
using a
powder diffractometer in order to determine its three-dimensional
structure. The observed peaks index on a monoclinic cell
with a =
5.444(7), b = 6.395(10), c = 8.680(5) angstrom, and gamma
=
99.6(3)degrees, V = 298 angstrom(3). One 2-fold helix
along the c-axis
can be accommodated in the unit cell. Molecular and packing
models have
been analyzed using the seven C-2'-endo/C-3'-endo allomorphs
originally
proposed by Radha and Chandrasekaran [Carbohydr. Res.
1997, 298, 105].
The generated powder pattern matches closely with the
observed
diffraction only for one C-2'-endo model. In this structure,
the three
main chain conformation angles are in the trans domains,
there are no
intra-chain hydrogen bonds, and the packing arrangement
is stabilized
by inter-chain O-3-(HO)-O-...-2 bonds.
DICVOL
2005-64
Yuan, WX Hu, JW Song, YT Wang, WJ
Xu, YP
Synthesis and structure of the ternary nitride Li6WN4
POWDER DIFFRACTION 20, 2005, 18-21.
The ternary nitridotungstate Li6WN4 has been synthesized via the solid
state reaction of lithium subnitride, Li3N, with W under
nitrogen. High
quality X-ray powder diffraction data were collected for
the
crystal-structure determination. Li6WN4 crystallizes in
the tetragonal
system, space group P4(2)/nmc, with cell parameters a
= 6.6759(3)
angstrom and c = 4.9280(3) angstrom, Z = 2. Preliminary
thermal
stability measurements of Li6WN4 show that it is sensitive
to moisture,
even at room temperature, and decomposes at high temperatures
below
1000 degrees C under flowing nitrogen.
DICVOL
2005-65
Hofmann, K Albert, B
Crystal structures of M-2[B10H10] (M = Na, K, Rb) via real-space
simulated annealing powder techniques
ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 142-146.
Alkali metal decahydro-closo-decaborates M-2[B10H10] (M = Na, K, Rb)
were synthesised by ion-exchange and characterised via
infrared and
B-11-NMR spectroscopy. The crystal structures of Na-2[B10H10,],
K-2[B10H10], and Rb-2[B10H10] were determined from X-ray
powder
diffraction data using real-space techniques. The compounds
crystallise
in the monoclinic space group P2(1)/n (no. 14) with the
lattice
constants: Na2[B10H10]: a = 1028.28(6) pm, b = 1302.18(5)
pm, c =
667.34(3) pm, beta = 93.754(3)degrees; K-2[B10H10]: a
= 1285.54(8) pm,
b = 1117.84(7) pm, c = 682.27(4) pm, beta = 93.357(3)degrees;
Rb-2[B10H10]: a = 1320.04(7) pm, b = 1136.88(6) pm, c
= 704.23(4) pm, P
= 94.158(3)degrees. The hydroborate anions are arranged
almost
hexagonally with alkali metal cations in the tetrahedral
interstices.
DICVOL
2005-66
Chui, SSY Ng, MFY Che, CM
Structure determination of homoleptic Au-I, Ag-I, and Cu-I
aryl/alkylethynyl coordination polymers by X-ray powder
diffraction
CHEMISTRY-A EUROPEAN JOURNAL 11, 2005, 1739-1749.
This article describes the structure determination of five homoleptic
d(10) metal-aryl/alkylacetylides [RC equivalent to CM]
(M=Cu, R=tBu 1,
nPr 2, Ph 3; R = Ph, M = Ag 4; Au 5) by using X-ray single-crystal
and
powder diffraction. Complex 1(.)C(6)H(6) reveals an unusual
Cu-20
catenane cluster structure that has various types of tBuC
equivalent to
C -> Cu coordination modes. By using this single-crystal
structure as a
starting model for subsequent Rietveld refinement of X-ray
powder
diffraction data, the structure of the powder synthesized
from CuI and
tBuC equivalent to CH was found to have the same structure
as 1.
Complex 2 has an extended sheet structure consisting of
discrete
zig-zag Cu-4 subunits connected through bridging nPrC
equivalent to C
groups. Complex 3 forms an infinite chain structure with
extended Cu-Cu
ladders (Cu-Cu = 2.49(4)-2.83 (2) angstrom). The silver(I)
congener 4
is iso-structural to 3 (average Ag-Ag distance 3.11 angstrom),
whereas
the gold(I) analogue 5 forms a (AuAu)-Au-... honeycomb
network with PhC
equivalent to C pillars (Au-Au = 2.98(1)-3.26(1) angstrom).
Solid-state
properties including photoluminescence, v(C equivalent
to C) stretching
frequencies and thermal stability of these polymeric systems
are
discussed in the context of the determined structures.
2005-67
Stock, N Guillou, N Senker, J Ferey,
G Bein, T
Synthesis and characterization of the tetraphosphonic acid ester
(Et2O3PCH2)(4)C6H2 and the open-framework cadmium tetraphosphonate,
Cd-2[(HO3PCH2)(4)C6H2]
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 575-581.
Following the strategy of using polyfunctional phosphonic acids for
the
synthesis of open-framework metal phosphonates, the ethyl
ester of a
tetraphosphonic acid, i. e. (Et2O3PCH2)(4)C6H2 (1) was
synthesized and
used in the hydrothermal synthesis of the new cadmium
tetraphosphonate,
Cd-2[(HO3PCH2)(4)C6H2] (2). The structure of 1 was solved
from single
crystal data (1: triclinic, P (1) over bar, a 12.3846(2),
b =
12.6166(3), c 12.9915(3) Angstrom, alpha = 86.380(1),
beta = 63.372(1),
gamma = 89.589(1)degrees, V = 1810.51(7) Angstrom3, Z
= 2, R1 = 0.077,
wR2 = 0.177). The in situ hydrolysis of the ethyl ester
and the
reaction with the Cd2+ ions leads to the well-crystallized
microcrystalline product 2. Its structure was solved and
refined using
X-ray powder diffraction data (2: triclinic, P (1) over
bar, with a =
11.0435(5), b = 7.5809(3), c = 5.4250(2) Angstrom, alpha
= 98.354(2),
beta = 101.951(2), gamma = 95.885(3)degrees, V = 435.48(9)
Angstrom3, Z
= 1, R(w)p = 0.096, R-P = 0.072, R-B = 0.081, R-F = 0.069).
Whereas the
structure of I is a molecular structure, the structure
of
Cd-2[(HO3PCH2)(4)C6H2] (2) is built up from edge sharing
CdO6 octahedra
forming dimeric [Cd2O10] polyhedra. In the second coordination
sphere
of each of the Cd-II ions six HO3PCH2R units are observed.
The [Cd2O10]
polyhedra are connected to six other [Cd2O10] polyhedra
by ten
hydrogenphosphonic acid units. Thus inorganic sheets are
formed that
are connected to a three-dimensional framework with small
channels,
through the phenyl rings. Thermogravimetric as well as
IR-,
Cd-13-MAS-NMR and P-31-MAS-NMR data are also presented.
DICVOL
2005-68
Abdelouhab, S Francois, M Elkaim, E
Rabu, P
Ab initio crystal structure of copper(II) hydroxy-terephthalate by
synchrotron powder diffraction and magnetic properties
SOLID STATE SCIENCES 7, 2005, 227-232.
The structure of Cu-2(OH)(2)(C8H4O4) has been determined by ab initio
XRPD methods from synchrotron data. The compound crystallizes
in P-1
space group, a = 10.1423(4) Angstrom, b = 6.3388(2) Angstrom,
alpha =
3.4841(1) Angstrom, alpha = 99.170(2)degrees, beta = 96.567(2)degrees,
gamma = 98.760(3)degrees, D-x = 2.497 g cm(-3). The structure
has been
fully refined by the Rietveld method down to R-p = 0.077
for 9651
observed data points (513 reflections of which 193 are
independent).
The structure consists of layered hydroxides Cu(OH)(2)
intercalated by
terephthalate anions, at the interlayer space forming
a 3D framework
similar to Co(II)-based compound. The apticity of the
tp anion and the
octahedral coordination of the metal ions are similar
in both compounds
and can be formulated as M-2(mu(3)-OH)(2)(A(6)-eta(1),
eta(2), eta(1),
eta(2)-tp) with M = Cu and Co. Although Cu(II)-based structure
is very
similar to the monoclinic (C2/m) Co(II)-based analogue,
the former is
completely ordered in contrast with the later which is
disordered. The
lower symmetry in Cu(II)-based compound due to the Jahn-Teller
effects
inducing an elongation of the octahedrons CuO6 with four
short
distances of about 2.0 Angstrom and two long distances
Cu-O up to 2.8
Angstrom is also observed to be different from Co(II)-based
compound.
Whereas the Co(II) derivative exhibits noncollinear antiferromagnetic
coupling between the ferrimagnetic hydroxide layers, the
magnetic
behavior of the copper(II) analogue indicate a ferromagnetic
coupling
through the terephthalate bridge between ferromagnetic
sheets with
in-plane interaction J = +5.5 K.
DICVOL
2005-69
Vanhoyland, G Pagnaer, J D'Haen, J
Mullens, S Mullens, J
Characterization and structural study of lanthanum citrate trihydrate
[La(C6H5O7)(H2O)(2)] . H2O
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 166-171.
[La(C6H5O7)(H2O)(2)] (.) H2O was synthesized as precursor material
for
an aqueous solution-get route to La-containing multimetal
oxides. The
compound was characterized by means of FTIR, TGA and pycnometry.
The
crystallographic structure was solved from powder diffraction
data. The
symmetry is monoclinic [a = 17.097(3) Angstrom, b = 9.765(2)
Angstrom,
c = 6.3166(8) Angstrom and beta = 90.42(1)degrees, Z(exp)
= 3.96] with
space group P2(1)/n (14). Direct methods were applied
and the model was
subsequently least-squares refined (R-B 5.1 % and R-wP
= 12.0%). La3+
is nine-fold coordinated, the LaO9 forming a mono-capped
square
antiprism. The basic unit is a binuclear entity of two
LaO9 polyhedra
having one edge in common. These units are connected along
the c-axis
through citrate molecules. The carboxylate groups of the
citrate are
coordinated to La3+ in monodentate, bidentate and bridging
way. Also
the alkoxide group, which carries the proton, is coordinated
to La3+.
Two water molecules complete the coordination sphere,
while the third
one can be found inbetween the La3+ -citrate network.
DICVOL
2005-70
Josse, M Dubois, M El-Ghozzi, M
Cellier, J Avignant, D
Anti-KSbF6 structure of CaTbF6 and CdTbF6: a confirmation of the
singular crystal chemistry of Tb4+ in flourides
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 1-10.
The crystal structures of two new tetravalent terbium fluorides, CaTbF6
(and CdTbF)(, have been determined from X-ray and neutron
powder
diffraction data. The title compounds exhibit an anti-KSbF)(6)(6)
(structure, the three-dimensional framework of which is
built of
[TbF)(]2- chains of edge-sharing dodecahedra further linked,
by sharing
corners, to isolated [MF)(]4- octahedra (M = Ca, Cd).
The mechanism of
the anionic sublattice rearrangement when going from KSbF)(6)(6)(6)
(to
CaTbF)(6) (is described and related to a simple cubic
fluoride-ion
packing. Comparison with the crystal structures of b-BaTbF)(6)
(and
other representatives of the MII MIVF)(6) family allows
the singular
crystal-chemical properties of some fluoroterbates to
be emphasized.
DICVOL
2005-71
Mora, AJ Avila, EE Delgado, GE Fitch,
AN Brunelli, M
Temperature effects on the hydrogen-bond patterns in
4-piperidinecarboxylic acid
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 96-102.
A temperature-controlled X-ray powder diffraction experiment,
complemented with TGA and DSC analysis, allowed us to
follow changes in
the molecular conformation and hydrogen-bond patterns
of
4-piperidinecarboxylic acid. The presence of three phases
is confirmed.
Phase 1 represents the monohydrated form of 4-piperidinecarboxylic
acid, which exists from room temperature to 359 K, where
dehydration
occurs. Phase 2 measured at 363 K corresponds to an anhydrous
form of
the acid. At ca 458 K the onset of a second, more gradual
transition is
observed, which ends at around 543 K. Phase 3 measured
at 543 K is a
high-temperature anhydrous form of the acid. The structures
of phases 2
and 3 were solved from synchrotron powder diffraction
data by simulated
annealing using the DASH program and refined by the Rietveld
method.
The phase changes are accompanied by modification of the
hydrogen-bond
patterns and of the torsional orientation of the terminal
carboxylate
group. This group makes a 49degrees rotation about the
C1 - C2 bond
during the first transition.
DICVOL
2005-72
Casellas, H Costantino, F Mandonnet, A
Caneschi, A Gatteschi, D
X-ray powder and single crystal structures of two unprecedented
families of bpca-based 1-D magnetic chains (Hbpca =
bis(2-pyridylcarbonyl)amine)
INORGANICA CHIMICA ACTA 358, 2005, 177-185.
Two unprecedented families of bpca-based mono-dimensional complexes
Cu(bpca)(X) (X = CN, 1; N-3, 2) and [Cu1-xFex(bpca)](ClO4)
(X = 0, 3;
0.23, 4) were synthesised. The structure of I was solved
ab initio from
X-ray powder diffraction data and refined by Rietveld
methods. The
complexes 3-4 were characterised by X-ray single crystal
diffraction.
In I the cyano ligand coordinates the metal centres, the
Cu centres
forming a zigzag 1-D chain along the (0 0 1) direction,
while in 3-4,
the bpca ligand itself acts as the link towards the metal
ions which
are arranged in a linear 1-D chain running parallel to
the (0 0 1)
direction. An infrared spectroscopy study confirmed these
coordination
modes. The magnetic properties of both chain families
were studied. 1-2
do not show significant magnetic interactions, whereas
the magnetic
behaviour for 3-4 suggests dominant antiferromagnetic
interactions
between the metal ions within the chains. The magnetic
behaviour of 3
was analysed using the Pade approximation of the Bonner-Fisher
model
for S = 1/2 antiferromagnetic chains. The J value was
estimated as 10
K.
DICVOL
2005-73 ???
Pitt, MP Blanchard, D Hauback, BC
Fjellvag, H Marshall, WG
Pressure-induced phase transitions of the LiAlD4 system
PHYSICAL REVIEW B 72, 2005, 214113
Compression of the LiAlD4 system has been studied using in situ
time-of-flight neutron diffraction up to 7.15 GPa and
60 degrees C. At
ambient temperature (T-a), the structure remains as monoclinic
alpha-LiAlD4 up to 7.05 GPa, displaying a 26.9% reduction
in unit cell
volume to 200.9 angstrom(3), yielding a 28.7% increase
in volumetric
efficiency to 136.5 kg D-2/m(3). Decompression to a small
3 ton load at
T-a and holding for 24 hours did not induce any phase
transformation,
and the starting 0 GPa alpha-LiAlD4 structure was eventually
recovered.
Heating from T-a to 60 degrees C while under compression
to 7.15 GPa
produces new and intense reflections in the diffraction
pattern, while
also retaining alpha-LiAlD4 reflections, indicating a
two-phase
alpha/beta-LiAlD4 mixture. The beta-LiAlD4 structure indexed
from this
data is in the monoclinic space group I2/b, with unit
cell dimensions
a=4.099(3) angstrom, b=4.321(4) angstrom, c=10.006(7)
angstrom,
gamma=88.43(2)degrees, yielding a volumetric efficiency
of 151.2 kg
D-2/m(3). The atomic arrangement in I2/b is identical
to that in the
theoretically predicted I4(1)/a super group, with isolated
symmetric
AlD4 tetrahedra displaying Al - D distances of 1.545(2)
angstrom. Once
again, decompression and cooling recovers the ambient
alpha-LiAlD4
structure.
2005-74
Svoboda, J Zima, V Benes, L Melanova,
K Vicek, M
Synthesis and characterization of new calcium phenylphosphonates and
4-carboxyphenylphosphonates
INORGANIC CHEMISTRY 44, 2005, 9968-9978.
Three new calcium phenylphosphonates, CaC6H5PO3-2H(2)O,
Ca-3(C6H5PO3H)(2)(C6H5PO3)(2)(.)4H(2)O, and CaC6H5PO3.
H2O, and two
calcium 4-carboxyphenylphosphonates, Ca(HOOCC6H4PO3H)2
and
Ca-3(OOCC6H4PO3)(2)(.)6H(2)O, were prepared. It was found
that
CaC6H5PO3-2H2O transformed into previously known Ca(C6H5PO3H)(2)
via
Ca-3(C6H5PO3H)(2)(C(6)H5PO(3))(2)(.)4H(2)O in the presence
of
phenylphosphonic acid, and vice versa, Ca(C6H5PO3H)(2)
turned into
CaC(6)H(5)PO(3)(.)2H(2)O in a weak basic medium. A similar
relationship
was found between Ca(HOOCC6H4PO3H)(2) and Ca-3(OOCC6H4PO3)(2)(.)6H(2)O;
i.e., Ca-3(OOCC6H4PO3)2(.)6H(2)O transformed into Ca(HOOCC6H4PO3H)(2)
in the presence of 4-carboxyphenylphosphonic acid. On
the contrary,
Ca-3(OOCC6H4PO3)2(.)6H(2)O is formed from Ca(HOOCC6H4PO3H)(2)
in the
presence of ammonium as a weak base. The structure of
Ca(HOOCC6H4PO3H)(2) was solved from X-ray powder diffraction
data by an
ab initio method using a FOX program. The compound is
monoclinic, space
group C21c (No, 15), a = 49,218(3) angstrom, b = 7.7609(4)
angstrom, c
= 5.4452(3) angstrom, beta = 128.119(3)degrees, and Z
= 4. Its
structure is one-dimensional with [Ca-2(HOOCC6H4PO3H)(4)](infinity)
ribbons forming basic building blocks. The ribbons are
held together by
hydrogen bonds between carboxylic groups.
2005-75 ???
Barrier, N Pelloquin, D Nguyen, N
Giot, M Bouree, F Raveau, B
Ferrite Sr3NdFe3O9: An original intergrowth between the brownmillerite
and K2NiF4-type structures
CHEMISTRY OF MATERIALS 17, 2005, 6619-6623.
The coupled neutron diffraction and Mossbauer study of the layered
oxide Sr3NdFe3O9 shows for the first time the possibility
of anionic
vacancies ordering in an oxygen-deficient related
Ruddlesden-Popper(RP-) type ferrite leading to an original
intergrowth
of brownmillerite and K2NiF4-type layers. The antiferromagnetic
properties of this phase up to 500 K are also evidenced.
These results
open the route to the synthesis of new members in the
series
(Sr2Fe2O5)(n) . SrLnFeO(4) and to the understanding
of their
reactivity with atmospheric water.
2005-76
Karau, F
Schnick, W
Preparation and crystal structure of diammin magnesium diazide
Mg(NH3)(2)(N-3)(2)
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 632, 2005, 49-53.
Diammin magnesium diazide was synthesized from Mg3N2 and NH4N3 in
liquid ammonia and crystallized at 150 degrees C under
autogenous
atmosphere of HN3 and NH3 using sealed ampoules. Mg(NH3)(2)(N-3)(2)
is
a colorless, microcrystalline powder which can detonate
above 180
degrees C. Caution, preparation and manipulation of Mg(NH3)(2)(N-2)(2)
is very dangerous! The crystal structure was solved from
powder data
using the Patterson method and a Rietveld refinement was
performed
(Mg(NH3)(2)(N-3)(2), I 4/m, no. 87; a = 6.3519(1), c =
7.9176(2)
angstrom; Z = 2, R(F-2) = 0.1162). The crystal structure
of
Mg(NH3)(2)(N-3)(2) is related to that of SnF4. It consists
of planes
built up from corner sharing Mg(NH3)2(N3)4 octahedra connected
equatorially over their four azide bridges with the ammonia
ligands
being in trans position. IR data were collected and interpreted
in
accordance with the structural data.
2005-77 ??
Marinkovic, BA Jardim, PM de Avillez, RR
Rizzo, F
Negative thermal expansion in Y2Mo3O12
SOLID STATE SCIENCES 7, 2005, 1377-1383
The crystal structure of Y2Mo3O12 was refined by the Rietveld method
for 130 degrees C as orthorhombic with space group Pbcn
(No. 60). It is
isostructural to Fe2Mo3O12 and consists of vertex sharing
YO6 and MoO4
building polyhedra. Y2Mo3O12 has very high negative thermal
expansion
along all three crystallographic directions in the 130-900
degrees C
temperature range. The overall linear coefficient of thermal
expansion
(alpha(1) = alpha(v)/3) is -1.26 x 10(-5) degrees C. Water
molecules
enter freely in Y2Mo3O12 microchannels and seem to have
a role in
partial amorphization of this compound at room temperature.
2005-78
Littner, A Francois, M Tobola, J
Elkaim, E Malaman, B Vilasi, M
Molten glass corrosion resistance of new Mo-Ru-Si compounds
MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION 56, 2005, 796-800.
AB In spite of a very promising potential for a large field of high
temperature applications, MoSi2 shows only a limited resistance
against
molten glass corrosion. Efforts to improve the performance
of
MoSi2-based materials led to the investigation of the
Mo-Ru-Si phase
diagram. The isothermal section at 1673 K revealed five
new
intermetallics with original structures. The crystallographic
study of
two of them was made using standard and synchrotron X-ray
measurements
combined with KKR (Korringa-Kohn-Rostoker) calculations.
The use of
such total energy electronic structure calculations was
helpful in
order to localize accurately Mo and Ru in the new compound
beta-Mo26Ru47Si27. This compound crystallizes in P4/mmm
space group
with a = 9.2164(l) angstrom, c = 2.88721 (1) angstrom,
Dx = 9.69(1)
g/cm(3). The structure has been refined by the Rietveld
method down to
R-p = 1. 1 %, R-B = 12.0 %, R-F = 8.7% for 6814 ob-served
data and 271
independent reflections. Moreover, electrochemical techniques
enabled
the determination of the redox properties of the new intermetallic
compounds. It has been shown that, in contact with molten
glass at 1623
K, Mo-Ru-Si compounds were subjected to electrochemical
reactions
leading to the simultaneous oxidation of silicon and molybdenum.
The
progressive superficial depletion of Si and Mo resulted
in the more or
less rapid formation of a thick, porous and low adherent
Ru-layer.
Consequently, the results showed that Ru-additions had
no positive
effect on the molten glass corrosion resistance of MoSi2-based
materials. The formation of a porous Ru-layer should even
accelerate
the degradation kinetics through galvanic coupling occurring
between
the superficial layer and the bulk material.
2005-79 ???
Li, LY Li, GB Wang, YX Liao, FH
Lin, JH
Bismuth borates: Two new polymorphs of BiB3O6
INORGANIC CHEMISTRY 44, 2005, 8243-8248.
Two new polymorphs of BiB3O6 were identified at low temperatures using
boric acid as a flux. Unlike alpha-BiB3O6, which crystallizes
in a
noncentrosymmetric space group and, thus, shows exceptional
nonlinear
optical (NLO) properties, beta-BiB3O6 (I) and gamma-BiB3O6
(II)
crystallize in the centrosymmetric space group P2(1)/n
with the
following lattice parameters: a = 14.1664(I), b = 6.7514(I),
c =
4.4290(I) angstrom, beta = 102.125(I)degrees for I; and
a = 8.4992(I),
b = 11.7093(I), c = 4.2596(I) angstrom, beta = 121.141(I)degrees
for
II. However, from the structural point of view, the three
polymorphs of
BiB3O6 are closely related. The structure of beta-BiB3O6
(I) contains a
2-dimensional borate layer, which could be considered
to be an
intralayered additive product of alpha-BiB3O6. On the
other hand, the
3-dimensional borate framework in gamma-BiB3O6 (II) could
be considered
to be an interlayered additive product of beta-BiB3O6
(I). According to
the synthesis experiments and calculated density, it is
proposed that
compounds I and II should be the low-temperature (high-pressure)
polymorphs of BiB3O6.
2005-80 ???
Oliveira, MF Kycia, SW Gomez, A
Kosar, AJ Bohle, DS
Hempelmann, E Menezes, D Vannier-Santos,
MA Oliveira, PL Ferreira, ST
Structural and morphological characterization of hemozoin produced
by
Schistosoma mansoni and Rhodhius prolixus
FEBS LETTERS 579, 2005, 6010-6016.
Hemozoin (Hz) is a heme crystal produced upon the digestion of
hemoglobin (Hb) by blood-feeding organisms as a main mechanism
of heme
disposal. The structure of Hz consists of heme dimers
bound by
reciprocal iron-carboxylate interactions and stabilized
by hydrogen
bonds. We have recently described heme crystals in the
blood fluke,
Schistosoma mansoni, and in the kissing bug, Rhodnius
prolixus. Here,
we characterized the structures and morphologies of the
heme crystals
from those two organisms and compared them to synthetic
P-hematin (beta
H). Synchrotron radiation X-ray powder diffraction showed
that all heme
crystals share the same unit cell and structure. The heme
crystals
isolated from S. mansoni and R. prolixus consisted of
very regular
units assembled in multicrystalline spherical structures
exhibiting
remarkably distinct surface morphologies compared to beta
H. In both
organisms, Hz formation occurs inside lipid droplet-like
particles or
in close association to phospholipid membranes. These
results show, for
the first time, the structural and morphological characterization
of
natural Hz samples obtained from these two blood-feeding
organisms.
Moreover, Hz formation occurring in close association
to a hydrophobic
environment seems to be a common trend for these organisms
and may be
crucial to produce very regular shaped phases, allowing
the formation
of multicrystalline assemblies in the guts of S. mansoni
and R.
prolixus.
2005-81
Barros-Garcia, FJ Bernalte-Garcia, A Cumbrera,
FL Lozano-Vila, AM
Luna-Giles, F Melendez-Martinez, JJ
Ortiz, AL
Synthesis, molecular characterization by infrared spectroscopy, and
crystal structure determination by X-ray powder diffractometry
of
[ZnCl2(TdTz)]
[TdTz=2-(3,4-dichlorophenyl)imino-N-(2-thiazin-2-yl)thiazolidine]
POLYHEDRON 24, 2005, 1975-1982.
The title zinc(II) complex, dichloro[2-(3,4-dichlorophenyl)imino-kappa
N-N-(2-thiazin-kappa N-2-yl)thiazolidine]zinc(II), was
synthesized in
the form of small crystals unsuitable for structure determination
by
X-ray single-crystal diffractometry. It was therefore
characterized
firstly in the solid state by elemental analysis and infrared
spectroscopy, and then its crystal structure was determined
by X-ray
powder diffractometry. The procedure followed to resolve
the crystal
structure used direct-space methods with a 'MonteCarlo/parallel
tempering' search algorithm, where the starting configuration
was
obtained by means of infrared spectroscopy and molecular
mechanics. A
final refinement of the crystal structure was performed
using the
Rietveld method. It was found that the environment around
the zinc(II)
ion may e described as a distorted tetrahedral geometry,
with the
metallic atom coordinated to two chlorine atoms [Zn-Cl(1)
= 2.158(5)
angstrom; Zn-Cl(2) = 2.145(4) angstrom], one imino nitrogen
[Zn-N(3) =
2.237(4) angstrom] and one thiazine nitrogen [Zn-N(1)
= 2.273(5)
angstrom]. In addition, we also report in this study the
crystal
structure of the
2-(3,4-dichlorophenyl)imino-N-(2-thiazin-2-yl)thiazolidine
(TdTz)
ligand determined by X-ray single-crystal diffractometry.
2005-82
Miller, SR Lear, E Gonzalez, J Slawin,
AMZ
Wright, PA Guillou, N Ferey, G
Synthesis and structure of the framework scandium methylphosphonates
ScF(H2O)CH3PO3 and NaSc(CH3PO3)(2) . 0.5H(2)O
DALTON TRANSACTIONS 20, 2005, 3319-3325.
Two framework scandium methylphosphonates have been prepared
hydrothermally and their structures solved. ScF(H2O) CH3PO3
is a
non-porous solid built up from - ScF - chains linked by
methylphosphonate groups. The ScO4F2 octahedra are completed
by a
coordinated water molecule. NaSc(CH3PO3)(2) .
0.5H(2)O was
solved ab initio from high-resolution synchrotron X-ray
powder
diffraction data. It has a fully connected, negatively
charged scandium
phosphonate framework where ScO6 octahedra share vertices
with PO3CH3
groups. The solid contains charge balancing sodium cations,
coordinated
by a water molecule, which may be reversibly removed and
adsorbed. The
structure of the perdeuterated, dehydrated solid has been
refined
against neutron powder diffraction data collected at 2.5
K, showing the
CD3 groups in a fully staggered orientation with respect
to the
phosphonate oxygen atoms.
2005-83
Belik, AA Azuma, M Matsuo, A Whangbo,
MH Koo, HJ
Kikuchi, J Kaji, T Okubo, S
Ohta, H Kindo, K Takano, M
Investigation of the crystal structure and the structural and magnetic
properties of SrCu2(PO4)(2)
INORGANIC CHEMISTRY 44, 2005, 6632-6640.
SrCu2(PO4)(2) was prepared by the solid-state method at 1153 K. Its
structure was solved by direct methods in the space group
Pccn (No. 56)
with Z = 8 from synchrotron X-ray powder diffraction data
measured at
room temperature. Structure parameters were then refined
by the
Rietveld method to obtain the lattice parameters, a =
7.94217(8)
angstrom, b = 15.36918(14) angstrom, and c = 10.37036(10)
angstrom.
SrCu2(PO4)(2) presents a new structure type and is built
up from Sr2O16
and Cu1Cu(2)O(8) units with Cu1 (...) Cu2 = 3.256 angstrom.
The
magnetic properties of SrCu2(PO4)(2) were investigated
by magnetic
susceptibility, magnetization up to 65 T, Cu nuclear quadrupole
resonance (NQR), electron-spin resonance, and specific
heat
measurements. With spin-dimer analysis, it was shown that
the two
strongest spin-exchange interactions between Cu sites
result from the
Cu1-0 (...) O-Cu2 and Cu2-0 (...) O-Cu2 super-superexchange
paths with
Cu1 (...) Cu2 = 5.861 angstrom and Cu2 (...) Cu2 = 5.251
angstrom, and
the superexchange associated with the structural dimer
Cu1Cu2O(8) is
negligible. The magnetic susceptibility data were analyzed
in terms of
a linear four-spin cluster model, Cu1-Cu2-Cu2-Cu1 with
-2J(1)/k(B) =
82.4 K for Cu1-Cu2 and -2J(2)/k(B) = 59 K for Cu-Cu2.
A spin gap
deduced from this model (Delta/k(B) = 63 K) is in agreement
with that
obtained from the Cu NQR data (Delta/k(B) = 65 K), A one-half
magnetization plateau was observed between approximately
50 and 63 T at
1.3 K. Specific heat data show that SrCu2(PO4)(2) does
not undergo a
long-range magnetic ordering down to 0.45 K. SrCu2(PO4)(2)
melts
incongruently at 1189 K. We also report its vibrational
properties
studied with Raman spectroscopy.
2005-84
Galli, S Masciocchi, N Cariati, E
Sironi, A
Barea, E Haj, MA Navarro, JAR
Salas, JM
Quest for second-harmonic-generation-active coordination polymers:
Synthesis and properties of silver(I) pyrimidinolates
CHEMISTRY OF MATERIALS 17, 2005, 4815-4824.
In the search for coordination compounds showing significant second
harmonic generation (SHG) activity, reaction of Ag(I)
ions with the
4-hydroxypyrimidine (4-Hpymo) and 5-nitro-2-hydroxypyrimidine
(HNP)
ligands generated four crystalline ID polymers, Ag(4-pymo)
.
nH(2)O (n = 2.5, 0), Ag(NP)(NH3), and Ag(NP), the latter
two
crystallizing in acentric space groups. Their synthesis,
complete
characterization, and structural determination, by conventional
single-crystal and laboratory X-ray powder diffraction
methods, are
presented and discussed in the frame of diazaaromatic-ligand-
and
metal-containing species. XRPD has also allowed the detection
of the
polyhydrated, elusive Ag(4-pymo) . nH(2)O (n = 2,
3) species.
Powders of Ag(NP) have shown an SHG activity close to
that of standard
urea. By applying the geometrical model proposed by Zyss,
it is shown
that the NP ligand is a highly promising chromophore,
the oxo and nitro
functionalities cooperatively promoting a high hyperpolarizability.
2005-85 ???
Staunton, E Andreev, YG Bruce, PG
Structure and conductivity of the crystalline polymer electrolyte
beta-PEO6 : LiAsF6
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 12176-12177.
2005-86 ???
Li, LY Li, GB Wang, YX Liao, FH
Lin, JH
Bismuth borates: One-dimensional borate chains and nonlinear optical
properties
CHEMISTRY OF MATERIALS 17, 2005, 4174-4180.
Three bismuth borates, Bi[B4O6(OH)(2)]OH (I), BiB2O4F (II), and
Bi-3[B6O13(OH)] (III), were obtained in boric acid flux
at low
temperatures and their structures were determined by using
single-crystal and powder X-ray diffraction techniques.
All these three
bismuth borates contain one-dimensional borate chains
and crystallize
in noncentrosymmetric space groups. I is a hydrated borate,
crystallizing, in the space group PI with lattice constants
a =
4.300(1) angstrom, b = 8.587(2) angstrom, c = 10.518(2)
angstrom, alpha
= 113.11(3)', 100.50(3)degrees, and beta = 90.36(3)degrees,
and the
borate chain consists of a 3-ring (2BO(3) + BO4) and a
BO3 group. II is
a fluoroborate, which crystallizes in the trigonal space
group P3(2)
with a = 6.7147(1) angstrom and c = 6.4688(1) angstrom,
and the borate
anion is a 3-fold helix chain formed by extensive linkage
of
three-membered borate rings (3BO(4)). III is also a hydrated
borate
with a structure that is closely related to 11, in which
one-sixth of
the borate groups are in triangular geometry (BOA which
reduces the
symmetry to P1, a = 6.6257(1) angstrom, b =6.6238(1) angstrom,
c =
6.6541(1) angstrom, and alpha = 89.998(3)degrees, beta
=
89.982(2)degrees, and gamma = 119.992(2)degrees. All these
three
bismuth borates exhibit nonlinear optical (NLO) properties.
2005-87
Dorset, DL Kennedy, GJ
Crystal structure of MCM-70: A microporous material with high framework
density
JOURNAL OF PHYSICAL CHEMISTRY B 109, 2005, 13891-13898.
The crystal structure of the borosilicate MCM-70 (siliceous framework
formula Si12O24) was determined from synchrotron powder
diffraction
data with the program FOCUS. The framework crystallizes
in space group
Pmn2(1), where a = 13.663, b = 4.779, c = 8.723 angstrom,
and forms ID
ellipsoidal 10-ring channels with the following dimensions:
5.0 x 3.1
angstrom. Rietveld refinement of the model against synchrotron
powder
data from solvated material gives Rwp = 0.15, R(F-2) =
0.11. In
addition to the four tetrahedral sites and seven framework
oxygens, one
potassium position is found during this refinement. Because
of the
unreasonable geometry of five putative extraframework
oxygen sites,
another synchrotron pattern was obtained from a dehydrated
specimen. A
refinement in space group P1n1 (removing the mirror operation
of
Pmn2(1)), where a = 13.670, b = 4.781, c = 8.687 angstrom,
and beta =
90.24 degrees, verified that the previous framework geometry
is
preserved as well as the potassium position. One extraframework
oxygen
was located that would yield a reasonable K-O distance.
The existence
of potassium is verified by electron energy dispersive
spectroscopic
measurements as well as quantitative elemental analysis.
(There are
approximately 2.35 K sites per 12 Si in the unit cell.)
It is likely
that the constricted channels occlude KOH. B-11 and Si-29
MAS NMR
measurements indicate a framework SiO2/B2O3 of approximately
40:1,
which is consistent with a wavelength dispersive spectroscopic
measurement. The silicate framework density is 2.10 gm/cm(3).
The
resulting framework density for T sites, 21.1, is unusually
high for a
zeolite, just below the value for paracelsian (21.4) or
scapolite
(21.8), each of which also has a smallest four-ring loop.
The H-1 ->
Si-29 CP MAS measurements suggest sample heterogeneity,
that is, a
portion of the sample that is strongly coupled to hydrogen
and
efficiently cross polarizes and another portion that does
not.
2005-88
Li, LY Liao, FH Li, GB Lin, JH
Synthesis and structure of a novel hydrated rare earth polyborate,
Ln[B5O8(OH)(2)] (Ln=Pr, Nd)
CHINESE JOURNAL OF INORGANIC CHEMISTRY 21, 2005, 949-954.
A novel hydrated rare earth polyborate, Ln[B5O8(OH)(2)] (Ln=Pr, Nd)
has
been synthesized by using boric acid as a flux at 200
degrees C. Its
crystal structure is established by powder X-ray diffraction
technique.
Ln[B5O8(OH)(2)] crystallizes in monoclinic space groupP2(1)/c.
The
title compounds consist of a double three-membered ring
composed of
three BO4 and two BO3 groups as the fundamental building
block. The FBB
shares four common oxygen atoms with the adjacent FBBs,
producing a
borate layer containing nine-membered borate ring window,
of which the
rare earth cations are located around the center. The
Ln(3+) cations
are coordinated with ten oxygen atoms from the nine-membered
ring
window and the adjacent borate layer. The borate layers
are stacked
along the b axis and are interlinked by the Ln-O bond.
2005-89
Irran, E Jurgens, B Schmid, S Schnick,
W
Synthesis, crystal structure determination from X-ray powder
diffractometry and vibrational spectroscopic properties
of
Mg[N(CN)(2)](2) . 4H(2)O
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 1512-1515.
Magnesium dicyanamide tetrahydrate Mg[N(CN)(2)](2)(.)4 H2O was
synthesized by aqueous ion exchange starting from Na[N(CN)(2)]
and
Mg(NO3)(2)(.)6 H2O. The crystal structure was solved and
refined on the
basis of powder X-ray diffraction data (P-21/c, Z = 2,
a 737.50(2), b =
732.17(1), c = 971.67(2) pm, beta = 98.074(1)degrees,
wR(P) = 0.059,
R-P = 0.046, R-F = 0.075). In the crystal there are neutral
complexes
[Mg[N(CN)(2)](2)(H2O)(4)] Which arc only connected via
hydrogen bonds.
Above 40 degrees C the tetrahydrate decomposes into anhydrous
Mg[N(CN)(2)](2).
2005-90
Barbier, J Penin, N Cranswick, LM
Melilite-type borates Bi2ZnB2O7 and CaBiGaB2O7
CHEMISTRY OF MATERIALS 17, 2005, 3130-3136.
The bismuth borates Bi2ZnB2O7 and CaBiGaB2O7 have been synthesized
by
solid-state reactions at temperatures in the 650-825 degrees
C range at
1 atm pressure. These compounds are the only synthetic
diborate members
of the melilite family, A(2)XZ(2)O(7), in which layers
of A cations
alternate with XZ(2)O(7) tetrahedral layers. Except for
CdBiGaB2O7, the
synthesis of other substituted bismuth borate melilites
has been
unsuccessful. The crystal structures of Bi2ZnB2O7 and
CaBiGaB2O7 have
been determined by powder X-ray diffraction and refined
by the Rietveld
method using powder neutron diffraction data. CaBiGaB2O7
adopts the
regular tetragonal melilite structure (P $(4) over bar
$2(1)m space
group, Z = 2) containing B2O7 tetrahedral dimers. The
refinement of
split eight-coordinated sites for the Ca2+ and Bi3+ interlayer
cations
suggests the presence of additional disorder. Bi2ZnB2O7
adopts a unique
orthorhombic melilite superstructure (Pba2 space group,
Z = 4)
containing both tetrahedral B2O7 and triangular B2O5 dimers.
The Bill
cations occupy two distinct interlayer sites with strongly
asymmetric
6-fold coordination environments. The preliminary measurement
of second
harmonic generation efficiencies (d(eff)) of powder samples
has yielded
values of 4.0 (Bi2ZnB2O7) and 1.6 (CaBiGaB2O7) relative
to a KH2PO4
standard.
2005-91
Ikeda, T Itabashi, K
RMA-3: synthesis and structure of a novel Rb-aluminosilicate zeolite
CHEMICAL COMMUNICATIONS iss 21, 2005, 2753-2755.
RMA-3 (Rubidium Microporous Aluminosilicate-3) was hydrothermally
synthesized from rubidium-aluminosilicate gels without
using any
organic or inorganic additives, and its structure determined
by XRD
Rietveld analysis was confirmed as a novel framework topology
containing two 8-membered ring pore-openings with dimensions
of 0.49 x
0.37 nm and 0.34 x 0.38 nm.
2005-92
Chi, LS Swainson, I Cranswick, L
Her, JH Stephens, P Knop, O
The ordered phase of methylammonium lead chloride CH3ND3PbCl3
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 1376-1385.
The perovskite-structured compound methylammonium lead chloride orders
into a low-temperature phase of space group Pnma, in which
at 80 K each
of the orthorhombic axes a = 11.1747(2) &ANGS;, b
= 11.3552(1) &ANGS;,
and c = 11.2820(1) &ANGS; is doubled with respect
to the room
temperature disordered cubic phase (a = 5.669 &ANGS;).
The structure
was solved by ab initio methods using the programs EXPO
and FOX. This
unusual cell basis for space group Pnma is not that of
a standard tilt
system. This phase, in which the methylammonium ions,
are ordered shows
distorted octahedra. The octahedra possess a bond angle
variance of
60.663(&DEG; 2) and a quadratic elongation of 1.018,
and are more
distorted than those in the ordered phase of methylammonium
lead
bromide. There is also an alternating long and short Pb-Cl
bond along
a, due to an off-center displacement of Pb within the
octahedron. This
suggests that the most rigid unit is actually the methylammonium
cation, rather than the PbCl6 octahedra, in agreement
with existing
spectroscopic data.
2005-93
Drache, M Roussel, P Conflant, P
Wignacourt, JP
Bi17Yb7O36 and BiYbO3 crystal structures. Characterization of thulium
and lutetium homologous compounds
SOLID STATE SCIENCES 7, 2005, 269-276.
Two new compounds Bi17Yb7O36 and BiYbO3 which were recently evidenced
in the Bi2O3-Yb2O3 system, have been characterized and
their structure
determined from X-ray diffraction powder data using the
Rietveld method
in an orthorhombic and a triclinic lattice, respectively.
The thulium
and lutetium homologous compounds have been prepared for
the first
time. They are isostructural to the ytterbium homologous.
The six
compounds have been characterized versus temperature by
DTA, X-ray
thermodiffractometry, and they systematically show a transformation
from their low temperature form, to a delta-Bi2O3-type
phase, occurring
on heating. For Bi(17)Ln(7)O(36), the delta-type phase
is obtained,
directly with Ln = Lu (870 degrees C) and Yb (855 degrees
C), and only
after an intermediate biphasic orthorhombic-cubic mixture
in the range
780-825 degrees C for Ln = Tm. For BiLnO(3), there is
a large
two-phased domain (delta-Bi2O3 + Ln(2)O(3) related phases)
from 955 to
1100 degrees C for Lu, 970 to 1200 degrees C for Yb and
980 to 1270
degrees C for Tm. The lattice constants thermal expansion
coefficients
have been determined from the cell parameters evolutions
versus
temperature. The conductivity properties of the Bi(17)Ln(7)O(36)
series, which could be obtained as ceramic pellets after
sintering in
the stability range of their low-temperature forms, have
been
investigated.
2005-94
Majzlan, J Botez, C Stephens, PW
The crystal structures of synthetics Fe-2(SO4)(3)(H2O)(5) and the type
specimen of lausenite
AMERICAN MINERALOGIST 90, 2005, 411-416.
An iron sulfate of nominal composition Fe-2(SO4)(3)(H2O)(5) has been
synthesized and its structure determined and refined by
high resolution
powder diffraction using synchrotron radiation. The structure
consists
of corrugated slabs in which iron octahedra are linked
by sulfate
tetrahedra in the monoclinic space group P2(1)/m with
lattice
parameters a = 10.711(1), b = 11.085(1), and c = 5.5747(5)
Angstrom,
beta = 98.853(3)degrees. We compare these results with
the type
specimen of lausenite from Jerome, Arizona, which has
monoclinic
lattice parameters a = 10.679(2), b = 11.053(3), and c
= 5.567(1)
Angstrom, beta = 98.89(1)degrees. Weight loss experiments
show that it
is currently a pentahydrate, despite earlier reports that
lausenite is
a hexahydrate. We argue that our synthetic material provides
a
structure determination for the type specimen of lausenite.
2005-95
Jurgens, B Irran, E Schnick, W
Synthesis and characterization of the rare-earth dicyanamides
Ln[N(CN)(2)](3) with Ln = La, Ce, Pr, Nd, Sm, and Eu
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 72-78.
The rare-earth dicyanamides Ln[N(CN)(2)](3) (Ln = La, Ce, Pr, Nd, Sm,
Eu) were obtained via ion exchange in aqueous medium and
subsequent
drying: The crystal structures were solved and refined
based on X-ray
powder diffraction data and they were found to be isotypic:
Ln[N(CN)(2)](3); Cmem (no. 63), Z = 4, Ln = La: a = 799.88(9)
pm, b =
11 58.2(1) pin, c = 1026.7(1) pm; Cc: a = 794.94(3) pm,
b =
1152.15(4)pm, c = 1020.96(4)pm; Pr: a = 790.45(5)pm, b
= 1146.19(6)pm,
c = 1016.74(6)pm; Nd: a 787.79(3)pm, b = 1144.59(4)pm,
c =
1015.54(4)pm; Sm: a = 781.30(5)pm, b = 1138.64(6)pm, c
= 1012.04(5)pm;
Eu: a 776.7(1)pm, b = 113 5. 1 (1) pm, c = 10 1 3.7(1)
pm). The
compounds represent the first dicyanamides with trivalent
cations. The
Ln(3+) ions are coordinated by three bridging N atoms
and six terminal
N atoms of the dicyanamide ions forming a three capped
trigonal prism.
The structure type is related to that of PuBr3. The novel
compounds
Ln[N(CN)(2)](3) have been characterized by IR and Raman
spectroscopy
(Ln = La) and the thermal behavior has been monitored
by differential
scanning calorimetry (Ln = Ce, Nd, Eu).
2005-96 ??
Li, ZF Sun, JL Wang, YX You, LP
Lin, JH
Structural and magnetic properties of Ba3La3Mn2W3O18
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 114-119.
A quaternary phase, Ba3La3Mn2W3O18, was synthesized in reduced
atmosphere (5% H-2/Ar) at 1200degreesC and characterized
by using
powder X-ray diffraction, electron diffraction and high
resolution TEM.
Ba(3)La(3)Mn(2)W3O(18) crystallizes in rhombohedral space
group R $(3)
over bar $m with the cell parameters, a = 5.7371(1) Angstrom
and c =
41.8336(5) Angstrom, and can be attributed to the n =
6 member in the
B-site deficient perovskite family, A(n)B(n)-O-1(3n).
The structure can
be described as close-packed [La/BaO3] arrays in the sequence
of
(hcccch)(3), wherein the B-site cations, W and Mn, occupy
five
octahedral layers in every six octahedral layers, which
leave a vacant
octahedral layers separating the 5-layer perovskite blocks.
The
B-cation layers in the perovskite block alternate along
the c-axis in a
sequence of W6+-Mn2+ -W5+ -Mn2+- W6+. The bond valence
calculation and
optical reflection spectrum confirm the presence of W5+.
This compound
behaves paramagnetically in wide temperature range and
weak
antiferromagnetic interaction only occurs at low temperatures.
2005-97
Tyutyunnik, AP Zubkov, VG Krasil'nikov, VN
Svensson, G Sayagues, MJ
Crystal structure of K2V8O21 and Tl2V8O21
SOLID STATE SCIENCES 7, 2005, 37-43.
The crystal structures of K2V8O21 and Tl2V8O21 have been determined
and
refined, using both neutron and X-ray powder diffraction
data. K2V8O21
(TI2V8O21) crystallises in the monoclinic space group
C2/m (C2/m) with
the unit cell parameters a = 14.9402(2) (15.1405(4)) Angstrom,
b =
3.61823(4) (3.61309(6)) Angstrom, c = 14.7827(2) (14.9712(2))
Angstrom
and beta = 91.072(1)degrees (89.967(2)degrees). The structures
consist
of VO6 octahedra and VO5 pyramids forming [V8O21](2-)
units running
along the b axis. These units can then be divided into
three columns:
(i) two edge-sbaring VO5 pyramids, (ii) columns of rock-salt
type
structure and (iii) single chains of VO5 pyramids. The
KM ions are
found in tunnels formed by the [V8O2](2-) units.
2005-98
Barrier, N Michel, C Maignan, A
Hervieu, M Raveau, B
CaMn4O8, a mixed valence manganite with an original tunnel structure
JOURNAL OF MATERIALS CHEMISTRY 15, 2005, 386-393.
A new mixed valent manganite CaMn4O8 with an original tunnel structure
has been synthesized. The host lattice of this oxide has
been
determined by X-ray powder diffraction, using ab initio
methods, and by
high resolution electron microscopy. It consists of single
and triple
chains of edge-sharing MnO6 octahedra, interconnected
through their
apices. The [Mn4O8](infinity) framework delimits three
types of
tunnels: six-sided ("H") and eight-sided ("8") where sit
the Ca2+
cations, and empty rutile-like tunnels ("R"). The analysis
of the Mn-O
inter-atomic distances shows that this structure could
also be
described from the association of only single chains of
edge-sharing
MnO6 octahedra, with single chains of edge-sharing MnO5
pyramids, and
evidences a high tendency of manganese to charge ordering.
Nanostructural mechanisms investigated by electron microscopy
also
allow the structure to be described in terms of single
bricks of four
Mn polyhedra, and evidence twinning and intergrowth phenomena
as well
as local ordering of calcium in the tunnels. The magnetic
measurements
show strong antiferromagnetic fluctuations at low temperature,
whereas
the low value of T-N similar to 90 K indicates that the
antiferromagnetic superexchange is weak in this oxide.
2005-99
Schmidt, MU Ermrich, M Dinnebier, RE
Determination of the structure of the violet pigment C22H12Cl2N6O4
from
a non-indexed X-ray powder diagram
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 37-45.
The violet pigment methylbenzimidazolonodioxazine, C22H12Cl2N6O4
(systematic name: 6,14-dichloro- 3,11-dimethyl-
1,3,9,11-tetrahydro-5,13-dioxa-7,15-diazadiimidazo[ 4,5-b:
4',5'-m]
pentacene-2,10-dione), shows an X-ray powder diagram consisting
of only
ca 12 broad peaks. Indexing was not possible. The structure
was solved
by global lattice energy minimizations. The program CRYSCA
[ Schmidt &
Kalkhof ( 1999), CRYSCA. Clariant GmbH, Pigments Research,
Frankfurt am
Main, Germany] was used to predict the possible crystal
structures in
different space groups. By comparing simulated and experimental
powder
diagrams, the correct structure was identified among the
predicted
structures. Owing to the low quality of the experimental
powder diagram
the Rietveld refinements gave no distinctive results and
it was
difficult to prove the correctness of the crystal structure.
Finally,
the structure was confirmed to be correct by refining
the crystal
structure of an isostructural mixed crystal having a better
X-ray
powder diagram. The compound crystallizes in P (1) over
bar, Z = 1. The
crystal structure consists of a very dense packing of
molecules, which
are connected by hydrogen bridges of the type N - H ...
O=C. This
packing explains the observed insolubility. The work shows
that crystal
structures of molecular compounds may be solved by lattice
energy
minimization from diffraction data of limited quality,
even when
indexing is not possible.
2005-100
Brazdova, V Ganduglia-Pirovano, MV Sauer, J
Crystal structure and vibrational spectra of AlVO4. A DFT study
JOURNAL OF PHYSICAL CHEMISTRY B 109, 2005, 394-400.
We present periodic density functional calculations within the
generalized gradient approximation (Perdew-Wang 91) on
structure and
vibrational properties of bulk AlVO4. The optimized structure
agrees
well with crystallographic data obtained by Rietveld refinement
(the
mean absolute deviation of bond distances is 0.032 A),
but the
deviations are larger for the lighter oxygen atoms than
for the heavier
Al and V atoms. All observed bands in the Raman and IR
spectrum have
been assigned to calculated harmonic frequencies. Bands
in the 1020-900
cm(-1) region have been assigned to V-O-(2) stretches
in V-O-(2)-Al
bonds. The individual bands do not arise from vibrations
of only one
bond, not even from vibrations of several bonds of one
VO4 tetrahedron.
The results confirm that vibrations around 940 cm(-1)
observed for
vanadia particles supported on thin alumina film are V-O-Al
interface
modes with 2-fold coordinated oxygen atoms in the V-O-(2)-Al
interface
bonds.
2005-101
Sperandeo, NR Karlsson, A Cuffini, S
Pagola, S Stephens, PW
The crystal structure and physicochemical characteristics of
2-hydroxy-N-[3(5)-pyrazolyl]-1,4-naphthoquinone-4-imine,
a new
antitrypanosomal compound
AAPS PHARMSCITECH 6, iss 4, 2005.
This study was designed to investigate the physical characteristics
and
crystalline structure of
2-hydroxy-N-[3(5)pyrazolyl]-1,4-naphthoquinone-4-imine
(PNQ), a new
active compound against Trypanosoma cruzi, the causative
agent of
American trypanosomiasis. Methods used included differential
scanning
calorimetry, thermogravimetry, hot stage microscopy, polarized
light
microscopy (PLM), Fourier-transform infrared (FTIR) spectroscopy,
and
high-resolution X-ray powder diffraction (HR-XRPD). According
to PLM
and HR-XRPD data, PNQ crystallized as red oolitic crystals
(absolute
methanol) or prisms (dimethyl sulfoxide [DMSO]-water)
with the same
internal structure. The findings obtained with HR-XRPD
data (applying
molecular location methods) showed a monoclinic unit cell
[a =
18.4437(1) angstrom, b = 3.9968(2) angstrom, c = 14.5304(1)
angstrom,
alpha = 90, beta = 102.71(6)degrees, = 90 degrees, V =
1044.9(1)
angstrom(3), Z = 4, space group P2(1)/c], and a crystal
structure
(excluding H-positions) described by parallel layers in
the direction
of the b-axis, with molecules held by homochemical (phenyl-phenyl
and
pyrazole-pyrazole) van der Waals interactions. In addition,
FTIR
spectra displayed the NH-pyrazole stretch overlapped with
the OH
absorption at 3222 cm(-1), typical of -NH and -OH groups
associated
through H-bondings; and a carbonyl stretching absorption
at 1694
cm(-1), indicating a non-extensively H-bonded quinonic
C=O, which was
in accordance with the solved crystal structure of PNQ.
The existence
of such cohesive forces shed light on the thermoanalytical
data, which
revealed that PNQ is a stable solid, unaffected by oxygen
that
decomposed without melting above 260 degrees C.
2005-102
Sofina, N Dinnebier, R Jansen, M
The crystal structure of disodium phosphonate, Na2HPO3
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 2994-2996.
Anhydrous disodium phosphonate, Na2HPO3, was prepared by dehydration
of
its pentahydrate. The crystal structure of Na2HPO3 was
solved from high
resolution X-ray powder diffraction data (P2(1)/n; Z =
4; a 9.6987(1),
b = 6.9795(1), c = 5.0561 (1) angstrom, beta = 92.37(1)degrees;
V =
341.97(1) angstrom(3)). The crystal structure consists
of two types of
sodium-oxygen polyhedra, which are connected via common
edges and
vertices forming layers perpendicular to [100]. These
Na(1)- and
Na(2)-layers are interlinked via common edges, forming
in a
3D-framework. The resulting topology is providing oxygen
arrangements
that please the coordinative requirement of phosphorus(III).
2005-103
Helliwell, JR Helliwell, M Jones, RH
Ab initio structure determination using dispersive differences from
multiple-wavelength synchrotron-radiation powder diffraction
data
ACTA CRYSTALLOGRAPHICA SECTION A 61, 2005, 568-574.
The purpose of this paper and a test case study is to assess a method
of ab initio structure solution from powder diffraction
data using f'
difference techniques. A theoretical foundation for the
approach used
is first provided. Then, with a test case ( nickel sulfate
hexahydrate), it is shown that both the position of the
anomalous
scatterer (Ni) can be determined and the structure can
be developed in
full. Specifically, synchrotron-radiation data were collected
at two
wavelengths close to the K edge for Ni and three wavelengths
remote
from the Ni absorption edge, at 1.3, 1.8 and 2.16 angstrom.
These five
wavelengths then allowed various combinations to be tried
to establish
which wavelength pairs gave the optimum signal in the
Patterson maps
using dispersive amplitude differences. The initial phases
derived from
the metal-atom position then allowed the structure to
be fully
developed by difference Fourier cycling. The relevance
of these
developments to structure-solution possibilities for proteins
via
powder dispersive difference data is then outlined.
2005-104
Dinnebier, RE Nuss, H Jansen, M
The crystal structures of solvent-free alkali-metal squarates from
powder diffraction data
ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 954-961.
The crystal structures of solvent-free lithium, sodium, rubidium, and
cesium squarates have been determined from high resolution
synchrotron
and X-ray laboratory powder patterns. Crystallographic
data at room
temperature of Li2C4O4: a = 7.1073(3) angstrom, b = 9.5627(4)
angstrom,
c = 3.2973(1) angstrom, beta = 101.11(1)degrees, V = 219.91
(1)
angstrom(3), monoclinic, C2/m, Z = 2, Na2C4O4: a 3.4925(1)
angstrom(3),
b = 6.8152(1) angstrom, c = 10.3525(2) angstrom, beta
= 91.56(1)degrees
V = 246.32(1) angstrom(3), monoclinic, P2(1)/c, Z = 2;
Rb2C4O4: a =
10.7908(5) angstrom, b = 6.8494(3) angstrom, c = 4.4521(2)
angstrom,
beta = 92.39(0), V = 328.77(4) angstrom(3), monoclinic,
C2/m, Z = 2;
Cs2C4O4: a = 1.1768(3)angstrom, b = 7.0453(2)angstrom,
c = 4.7424(1)
angstrom, beta = 92.89(1)degrees; V = 372.97(4) angstrom(3),
monoclinic, C2/m, Z = 2. The packing features of lithium
squarate can
be deduced from the AlB2 structure type, while sodium,
rubidium, and
cesium squarate are related to the CdI2 type. The relation
between the
two types of crystal structures of the squarate dianion
is discussed.
2005-105
Dinnebier, RE Nuss, H Jansen, M
Disodium rhodizonate: a powder diffraction study
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61, 2005,
M2148-M2150.
The crystal structure of the title compound, disodium
1,2,3,4-tetraoxo-5-cyclohexene-5,6-diolate, 2Na(+)
. C6O62+,
is built up of alternating layers of hexagonally packed
Na+ cations and
rhodizonate dianions. The rhodizonate dianion has a slightly
twisted
conformation.
2005-106
Kirik, SD Mulagaleev, RF Blokhin, AI
[Pd-8(CH3COO)(8)(NO)(8)]: solution from X-ray powder diffraction data
ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 61,
2005, M445-M447.
The water-insoluble title compound, octakis(mu-acetato-kappa(2)O:O)
octakis(mu-nitroso-kappa(2)N:O) octapalladium(II),
[Pd-8(CH3COO)(8)(NO)(8)], was precipitated as a yellow
powder from a
solution of palladium nitrate in nitric acid by adding
acetic acid. Ab
initio crystal structure determination was carried out
using X-ray
powder diffraction techniques. Patterson and Fourier syntheses
were
used for atom locations, and the Rietveld technique was
used for the
final structure refinement. The crystal structure is of
a molecular
type. The skeleton of the [Pd-8(CH3COO)(8)(NO)(8)] molecule
is
constructed as a tetragonal prism with Pd atoms at the
vertices. The
eight NO- groups are in bridging positions along the horizontal
edges
of the prism. The N and O atoms of each nitroso group
coordinate two
different Pd atoms. The vertical edges present Pd
. .
. Pd contacts with a short distance of 2.865
(1) angstrom.
These Pd atoms are bridged by a pair of acetate groups
in a cis
orientation with respect to each other. The complex has
crystallographically imposed 4/m symmetry; all C atoms
of the acetate
groups are on mirror planes. The unique Pd atom lies in
a general
position and has square-planar coordination, consisting
of three O and
one N atom.
2005-107
Dinnebier, RE Nuss, H Jansen, M
Anhydrous CuC4O4, a channel structure solved from X-ray powder
diffraction data
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 2328-2332.
The crystal structure of the new anhydrous metal squarate CUC4O4 was
solved from laboratory X-ray powder diffraction data.
It crystallizes
in the monoclinic space group I2/a (no. 15) with the lattice
parameters
a = 5.6747(1), b = 8.9394(4), c = 9.4987(4) angstrom und
beta =
94.372(2)degrees at ambient conditions (Z = 4, R-F(2)
= 8.24%). The
crystal structure can be reduced to a defect variant of
the AIB(2) type
of structure ([C4O4][Cu square] double left right arrow
[Al][B-2]) and
shows channels parallel to the a axis with a free diameter
of about 2.3
angstrom. The squarate dianion, [C4O4](2-), is acting
as a
mu(6)-ligand, in this case.
2005-108
Solovyov, LA Astachov, AM Molokeev, MS
Vasiliev, AD
Powder diffraction crystal structure analysis using derivative
difference minimization: example of the potassium salt
of
1-(tetrazol-5-yl)-2-nitroguanidine
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 435-442.
The crystal structure of the potassium salt of 1-( tetrazol- 5- yl)-2-
nitroguanidine [K(C2H3N8O2)] was solved and refined from
X-ray powder
diffraction data by applying the derivative difference
minimization
(DDM) method. The compound is of interest as an energetic
substance.
The structure model was found from a Patterson search.
The reflection
intensities for the Patterson synthesis were derived from
the powder
profile by applying a newly developed DDM-based profile
decomposition
procedure. The use of the DDM method allowed successful
location and
unconstrained refinement of all the atomic positions,
including those
of three independent H atoms. The advantages of DDM in
terms of the
precision and reproducibility of the structural parameters
are
discussed in comparison to Rietveld refinement results.
The failure to
refine the H-atom positions by the Rietveld method was
attributed to
systematic errors associated with the background modelling,
which are
avoided by DDM.
2005-109
El-Himri, A Nunez, P Sapina, F Beltran,
A
Freeze-dried precursor-based synthesis of new polymetallic oxynitrides,
V1-u-zCruMoz(OxNy),V1-u-zCruWz(OxNy), Cr1-u-zMouWz(OxNy)
(u, z=0.2,
0.33, 0.4, 0.6, u plus z < 1), and VzCrzMozWz(OxNy)
(z=0.25)
JOURNAL OF ALLOYS AND COMPOUNDS 398, 2005, 289-295.
Interstitial polymetallic oxynitrides in the solid solution series
V1-u-zCruMoz(OxNy), V1-u-zCruWz(OxNy) and Cr1-u-zMouWz(OxNy)
(u, z=0.2,
0.33, 0.4, 0.6, u+z < 1), as well as the tetrametallic
VzCrzMozWz(OxNy)
(z=0.25) composition, can be obtained by ammonolysis of
precursors
resulting from the freeze-drying of aqueous solutions
of the simple
metal salts NH4VO3, (NH4)(2)CrO4, (NH4)(6)Mo(7)O(24) .
4H(2)O
and (NH4)(6)W(12)O(39) . 18H(2)O. A study of the
influence of
the preparative variables on the outcomes of this procedure
is
presented. Compounds in the V1-u-zCruMoz(OxNy) series
have been
prepared as single phases by direct ammonolysis of the
respective
freeze-dried precursors during 2h at 1173 K, followed
by fast cooling
of the samples. In contrast, the preparation of compounds
in both the
V1-u-zCruWz(OxNy) and the Cr1-u-zMouWz(OxNy) series requires
the
intermediate formation of crystalline precursors. These
last compounds
result from thermal treatment in air at 973 K, during
12 h, of the
corresponding freeze-dried powders. Then, they were subjected
to
ammonolysis, during 2 h, at 1123 K (V containing series)
or 1173 K (Mo
containing series), followed by slow cooling of the samples.
The
tetrametallic VzCrzMozWz(OxNy) compound also has been
prepared as
single phase by ammonolysis of the crystalline intermediate
at 1073 K,
during 2 h, followed by slow cooling. All the compounds
in these series
have the rock-salt crystal structure, in which the metal
atoms are in a
face-centred cubic arrangement, with non-metal atoms occupying
octahedral interstitial positions. The materials have
been
characterized by X-ray powder diffraction, elemental analysis,
thermogravimetric analysis under oxygen flow and scanning
electron
microscopy.
2005-110
Hildebrandt, L Dinnebier, R Jansen, M
Crystal structure and ionic conductivity of cesium trifluoromethyl
sulfonate, CSSO3CF3
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 1660-1666.
The crystal structures of the room and the high temperature
modifications of cesium trifluoromethyl sulfonate were
solved from high
resolution X-ray powder diffraction data. At room temperature,
alpha-CsSO3CF3 crystallizes in the monoclinic space group
P2(1) with
lattice parameters a = 9.7406(2) angstrom, b = 6.1640(1)
angstrom, c =
5.4798(1) angstrom, and beta = 104.998(1)degrees; Z =
2. At
temperatures above T = 380 K, a second order phase transformation
towards a disordered C-centered orthorhombic phase in
space group Cmcm
occurs with lattice parameters at T = 492 K of a = 5.5074(3)
angstrom,
b = 19.4346(14) angstrom, and c = 6.2978(4) angstrom;
Z = 4. Within the
crystal structures, the triflate anions are arranged in
double layers
with the apolar CF3-groups pointing towards each other.
The cesium ions
are located between the SO3-groups. CsSO3CF3 shows a specific
ion
conductivity ranging from sigma = 1.06 . 10(-8)
Scm(-1) at T =
393 K to sigma = 5.18 . 10(-4) Scm(-1) at
T = 519 K.
2005-111
Khalyavin, DD Senos, AMR Mantas, PQ
Crystal structure of La4Mg3W3O18 layered oxide
JOURNAL OF PHYSICS-CONDENSED MATTER 17, 2005, 2585-2595.
The crystal structure of A-site deficient La4M93W3O18 perovskite has
been solved by x-ray powder diffraction in combination
with group
theoretical analysis. Above 700 K, the crystal structure
is
orthorhombic (space group Ibam; 2a(p) x 4a(p) x 2a(p)
type
superstructure) and presents a sequence of
[LaO]-[Mg1/2W1/2O2]-[La1/3O]'-[Mg1/2W1/2O2]-[LaO]-[Mg1/2W1/2O2]-[La1/3O]
"-[Mg1/2W1/2O2] layers stacked along the b axis. The lanthanum
ions and
the vacancies in the [La1/3O]' and [La1/3O]" layers are
ordered and
form rows along the c axis. A half-period shift along
the a direction
between these layers leads to a quadrupling of the primitive
perovskite
unit cell in the b direction. The ordering of the vacancies
in the
lanthanum poor layers is connected with the ionic ordering
between Mg2+
and W6+ in the neighbouring [Mg1/2W1/2O2] blocks. Around
700 K, due to
an anti-phase rotation of the octahedra, a continuous
phase transition
mediated by the Gamma(2)(+) irreducible representation
from
orthorhombic (Ibam, a(0)b(0)c(0)) to monoclinic (C2/m,
a(0)b(0)c(-))
symmetry takes place.
2005-112
Li, DY O'Connor, B van Riessen, A
Mackinnon, C Low, IM
Structural determination of high T-c superconductor (Bi,
Pb)(2)Sr2Ca2Cu3Ox(2223) phase with powder diffraction
data
SUPERCONDUCTOR SCIENCE & TECHNOLOGY 18, 2005, 373-380.
The (Bi, Pb)(2)SrCa2Cu3Ox (2223) phase is regarded as the one of the
most technologically significant high T-C phases in the
Bi-Sr-Ca-Cu-O
system. However, its structure has not been fully described
so far. The
definitive structure model of 2223 has been determined
in this study by
direct methods and Q-peak analysis of difference Fourier
maps using
synchrotron radiation data. Successive least squares refinement
of the
model with the preferred A2aa space group was carried
out by Rietveld
procedures with neutron diffraction data. Anomalies were
not observed
for interatomic distances (bonded and non-bonded atoms),
bond angles
and isotropic temperature parameters. Two categories of
copper atoms
were clearly identified: (i) square coordinated to four
oxygen atoms
and (ii) pyramids with a fifth oxygen atom. The valence
states of two
Cu atoms have been estimated using bond valence calculations,
as
employed by Brown for YBCO. There is no direct bridging
between the Cu
squares and pyramids. The Bi3+ cations are coordinated
by three oxygen
atoms and form a single chain [BiO2](n)(n-) along the
a axis, which is
the first report of this feature for the 2223 structure.
2005-113
Vensky, S Kienle, L Dinnebier, RE
Masadeh, AS Billinge, SJL Jansen, M
The real structure of Na3BiO4 by electron microscopy, HR-XRD and PDF
analysis
ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 231-244.
The real structure of a new crystalline high temperature phase,
metastable at room temperature, in the system sodium -
bismuth -
oxygen, beta-Na3BiO4, was determinated using high resolution
X-ray
powder diffraction, pair distribution function analysis,
and high
resolution transmission electron microscopy. beta-Na3BiO4
was
synthesized by anodic oxidation of bismuth(III)-oxide
in a sodium
hydroxide - lithium hydroxide melt. The average crystal
structure of
beta-Na3BiO4 at ambient conditions (R(3) over bar m, a
= 3.32141(9)
angstrom, c = 16.4852(5) angstrom) is structurally related
to
alpha-NaFeO2 With metal layers almost statistically occupied
in a Na:
Bi ratio of 3: 1. Analysis of the long-range order on
the bulk material
by Rietveld refinement led to approximately Na: Bi ratios
of 2: 1 and
4: 1, in consecutive metal layers, while a detailed analysis
of the
local order by means of the pair distribution function
revealed the
existence of almost pure sodium layers and mixed 1: 1
- sodium: bismuth
layers. Complementary studies on single crystallites using
high
resolution transmission electron miscroscopy exhibited
a complex domain
structure with short-range ordered, partially ordered,
and long-range
ordered domains.
2005-114
Solovyov, LA Belousov, OV Dinnebier, RE
Shmakov, AN Kirik, SD
X-ray diffraction structure analysis of MCM-48 mesoporous silica
JOURNAL OF PHYSICAL CHEMISTRY B 109, 2005, 3233-3237.
The structure of MCM-48 mesoporous silicate materials has been fully
characterized from X-ray diffraction data by applying
recently
developed methods of mesostructure analysis and full-profile
refinement. The pore wall thickness of both as-made and
calcined MCM-48
was determined with high precision to be 8.0(1) Angstrom.
No regular
variations of the wall thickness were detected, but its
density was
found to be ca. 10% higher in the low-curvature regions.
The surfactant
density in the pores was assessed around 0.6-0.7 g/cm(3)
and was found
to have a distinct minimum in the pore center similar
to that detected
previously in MCM-41. A new extended model function of
the density
distribution in MCM-48 is proposed on the basis of the
structural
features that were revealed.
2005-115
Dinnebier, RE Vensky, S Jansen, M
Hanson, JC
Crystal structures and topological aspects of the high-temperature
phases and decomposition products of the alkali-metal
oxalates
M-2[C2O4] (M = K, Rb, Cs)
CHEMISTRY-A EUROPEAN JOURNAL 11, 2005, 1119-1129.
The high-temperature phases of the alkali-metal oxalates M-2[C2O4]
(M=K, Rb, Cs), and their decomposition products M-2[CO3]
(M=K, Rb, Cs),
were investigated by fast, angle-dispersive X-ray powder
diffraction
with an image-plate detector, and also by simultaneous
differential
thermal analysis (DTA)/thermogravimetric analysis (TGA)/mass
spectrometry (MS) and differential scanning calorimetry
(DSC)
techniques. The following phases, in order of decreasing
temperature,
were observed and crystallographically characterized (an
asterisk
denotes a previously unknown modification): *alpha-K-2[C2O4],
*alpha-Rb-2[C2O4], *alpha-Cs-2[C2O4], alpha-K-2[CO3],
*alpha-Rb-2[CO3],
and *alpha-Cs-2[CO3] in space group P6(3)/mmc; *beta-Rb-2[C2O4],
*beta-Cs-2[C2O4], *beta-Rb-2[CO3], and *beta-Cs-2[CO3]
in Pnma;
gamma-Rb-2[C2O4], gamma-Cs[C2O4], gamma-Rb-2[CO3], and
gamma-Cs-2[CO3]
in P2(1)/c; and delta-K-2[C2O4] and delta-Rb-2[C2O4] in
Pbam. With
respect to the centers of gravity of the oxalate and carbonate
anions,
respectively, the crystal structures of all known alkali-metal
oxalates
and carbonates belong to the AlB2 family, and adopt either
the AlB2 or
the Ni2In arrangement depending on the size of the cation
and the
temperature. Despite the different sizes and constitutions
of the
carbonate and oxalate anions, the high-temperature phases
of the
alkali-metal carbonates M-2[CO3] (M=K, Rb, Cs), exhibit
the same
sequence of basic structures as the corresponding alkali-metal
oxalates. The topological aspects and order-disorder phenomena
at
elevated temperature are discussed.
2005-116
Ahlert, S Dinnebier, R Jansen, M
The crystal structures of the high-temperature phases of Ag4Mn3O8
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 90-98.
Two endothermic, reversible structural phase transitions of first order
have been observed in Ag4Mn3O8 by means of in-situ powder
diffraction
and by differential scanning calorimetry. At a temperature
of T = 477
K, Ag4Mn3O8 undergoes a structural phase transition from
the room
temperature phase in space group P3(1)21 to a phase in
space group R32,
and at T = 689 K a second phase transition to a structure
in space
group P4(3)32 occurs. Whilst the Mn3O8 framework does
not change
significantly upon heating, rearrangements of the silver
atoms, located
in the cavities of the framework, were found to be the
driving force
behind the transitions. The structural chances with increasing
temperature proceed along a path of minimal group-supergroup
relations
between the respective space groups.
2005-117
Pan, ZG Cheung, EY Harris, KDM Constable,
EC Housecroft, CE
A case study in direct-space structure determination from powder X-ray
diffraction data: Finding the hydrate structure of an
organic molecule
with significant conformational flexibility
CRYSTAL GROWTH & DESIGN 5, 2005, 2084-2090.
The structure of the monohydrate crystalline phase of
3,5-bis((3,4,5-trimethoxybenzyl)oxy)benzyl alcohol has
been determined
directly from powder X-ray diffraction data using the
direct-space
genetic algorithm technique for structure solution followed
by Rietveld
refinement. This work raises several issues of a general
nature
concerning the assessment of results obtained in the structure
determination of organic molecular solids from powder
X-ray diffraction
data and serves as a case study that may find wider relevance
in this
field.
2005-118
Okudera, H Dinnebier, RE Simon, A
The crystal structure of gamma-P-4, a low temperature modification
of
white phosphorus
ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 259-264.
The crystal structure of gamma-P-4, one of three modifications hitherto
reported on white phosphorus, was determined from X-ray
powder
diffraction data collected at T = 123 K on a Guinier-Simon
camera
equipped with a cold gas blower and an image plate detector.
Crystallographic data at T = 123 K are: space group C2/m,
a = 9.1709(5)
angstrom, b 8.3385(5) angstrom, c = 5.4336(2) angstrom,
and beta =
90.311(3)degrees, V 415.51(6) angstrom(3), Z = 4. The
crystal structure
Of gamma-P4 was solved by the method of simulated annealing.
The
subsequent Rietveld refinement in the range 12 degrees
< 20 < 92
degrees employing rigid-body constraints on the P-4 molecule
converged
at R-p = 3.8, wR(p) = 5.0, and R-F(2) = 14.0%. The asymmetric
unit Of
gamma-P-4 contains three P atoms; two P atoms in a molecule
are related
by a mirror plane which bisects the molecule. The centers
of gravity of
these P-4 molecules show a distorted body-centered cubic
arrangement.
The four apices of the P-4 tetrahedron point to the largest
possible
voids formed by neighbor molecules. The difference to
the crystal
structures of SiF4 and GeF4 with an exact bcc arrangement
of
tetrahedral molecules is discussed as well as, in terms
of layer
stackings, the similarity of the structures of gamma-
and beta-P-4.
2005-119
Ryabova, SY Rastorgueva, NA Sonneveld, EJ
Peschar, R
Schenk, H Tafeenko, VA Aslanov,
LA Chernyshev, VV
Structural characterization of [1,4]diazepino[6,5-b]indoles by powder
diffraction
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 192-199.
As part of a systematic structural study of potentially
pharmacologically active [1,4] diazepino[6,5-b] indoles,
the crystal
structures of nine compounds have been determined from
laboratory
powder diffraction data. The investigated compounds are:
2-oxo-1-(4-nitrophenyl)- 1,2,3,6-tetrahydro[ 1,4] diazepino[
6,5-b]
indole-4-oxide, C17H12N4O4 (1a); 2-oxo-
1-phenyl-1,2,3,6-tetrahydro[1,4] diazepino[6,5-b] indole-4-oxide,
C17H13N3O2 (1b); 2-oxo-1-(4-ethoxyphenyl)-1,2,3,6-tetrahydro[
1,4]
diazepino[6,5-b] indole-4-oxide, C19H17N3O3( 1c); 2-oxo-
1-(4-chlorophenyl)- 1,2,3,6- tetrahydro[ 1,4] diazepino[
6,5-b]
indole-4-oxide, C17H12N3O2Cl (1d); 2-oxo-1-(4-cyanophenyl)-
1,2,3,6-tetrahydro[1,4] diazepino[6,5-b] indole-4-oxide,
C18H12N4O2
(1e); 6-methyl-2-oxo-1-phenyl-1,2,3,6-tetrahydro[ 1,4]
diazepino[6,5-b]
indole-4-oxide, C18H15N3O2 (1f); 2-formyl-3-[N'-(omega-chloracetyl)-
N'-(4-nitrophenyl)] aminoindole, C17H12N3O4Cl (2a);
2-formyl-3-[N'-(omega-chloracetyl)N'-( 4-nitrophenyl)]
aminoindole
solvate with toluene (2: 1), C17H12N3O4Cl .
0.5C(7)H(8) (2as);
2-formyl-3-[N'-(omega-chloracetyl)N'-( 4-cyanophenyl)]
aminoindole,
C18H12N3O2Cl (2e). Compounds ( 1a) -( 1f) crystallize
in
non-centrosymmetric triclinic, monoclinic and orthorhombic
space
groups. The three-dimensional structures of ( 1a) -( 1e)
demonstrate
identical intermolecular NH( indole) .
. .
O<--N hydrogen bonds, which form linear chains of connected
molecules.
A comparison of the crystal structures ( 2a), ( 2e) and
( 2as) shows
that the solvent used in the re-crystallization of ( 2a)
and ( 2e),
which are intermediates in the synthesis of ( 1a) and
( 1e), affects
the intermolecular hydrogen-bond formation and, as a result,
leads to
essentially different yields of the goal products.
2005-120
Stride, JA
Determination of the low-temperature structure of hexamethylbenzene
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 200-206.
The low-temperature structure of hexamethylbenzene has been determined
from neutron powder diffraction data and found to differ
from the
room-temperature phase predominantly by a translation
of molecular
planes to a form a cubic close-packed type structure.
By performing
measurements as a function of temperature, the role of
thermally
induced agitation of the molecular units in the first-order
phase
transition is clearly demonstrated.
2005-121
Guillou, N Livage, C Chaigneau, J
Ferey, G
Structural investigation of the nickel 3-methylglutarate from powder
diffraction demonstrating adaptability of the inorganic
skeleton of
MIL-77
POWDER DIFFRACTION 20, 2005, 288-293.
Ni-20[(C6H8O4)(20)(H2O)(8)] . 33H(2)O, a new nickel(II)
3-methylglutarate, was prepared hydrothermally (180 degrees
C, 48 h,
autogenous pressure) from a 1: 1.5:2:180 mixture of nickel
(II)
sulphate hexahydrate, 3-methylglutaric acid, sodium hydroxide,
and
water. It crystallizes in the cubic system (space group
P4(3)32, Z=1)
with a = 16.8488(5) angstrom and V=4783.1(4) angstrom(3).
Its structure
was solved from conventional X-ray powder diffraction
data. It presents
a three-dimensional network of edge-sharing nickel octahedra,
lined by
deprotonated organic anions. This remarkable oxide network
with
corrugated 20-membered rings is constructed from homochiral
helices.
The rings intersect each other to generate large crossing
channels full
of water along [111].
2005-122
Fossdal, A Brinks, HW Fichtner, M
Hauback, BC
Determination of the crystal structure of Mg(AlH4)(2)by combined X-ray
and neutron diffraction
JOURNAL OF ALLOYS AND COMPOUNDS 387, 2005, 47-51.
The structure of magnesium alanate, Mg(AlH4)(2), has been examined
in
detail by combined powder synchrotron X-ray and neutron
diffraction.
The space group is confirmed to be P (3) over barm 1 with
unit cell
dimensions of a = 5.2084(3) Angstrom and c = 5.8392(5)
Angstrom at 8 K,
a = 5.20309(12) Angstrom and c = 5.8400(2) Angstrom at
111 K and a =
5.1949(2) Angstrom and c = 5.8537(2) Angstrom at 295 K.
The structure
consists of isolated and slightly distorted AlH4- tetrahedra
that are
connected via six-coordinated Mg atoms in a distorted
octahedral
geometry, resulting in a sheet-like structure along the
crystallographic c-axis. The distortion of the AlH4- tetrahedra
decreases with increasing temperature, whereas, the opposite
is the
case for the MgH6 octahedra. The Al-H distances are 1.606(10)-1.634(4)
Angstrom, 1.602(10)-1.682(3) Angstrom and 1.561(12)-1.672(4)
Angstrom
at 8, 111 and 295 K, respectively.
2005-123
Brandel, V Clavier, N Dacheux, N
Synthesis and characterization of uranium(IV)
phosphate-hydrogenphosphate hydrate and cerium(IV)
phosphate-hydrogenphosphate hydrate
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 1054-1063.
A new uranium (IV) phosphate of proposed formula
U-2(PO4)(2)(HPO4H2O)-H-., i.e. uranium phosphate-hydrogen
phosphate
hydrate (UPHPH), was synthesized in autoclave and/or in
polytetrafluoroethylene closed containers at 150 degrees
C by three
ways: from uranium (IV) hydrochloric Solution and phosphoric
acid, from
uranium dioxide and phosphoric acid and by transformation
Of the
uranium hydrogenphosphate hydrate U(HPO4)(2)(.)nH(2)O.
The new product
appears similar to the previously published thorium
phosphate-hydrogenphosphate hydrate Th-2(PO4)(2)(HPO4H2O)-H-.
(TPHPH).
From preliminary studies, it was found that UPHPH crystallizes
in
monoclinic system (a = 2.1148(7) nm, b = 0.6611(2) nm,
c = 0.6990(3)
nm, beta = 91.67(3)degrees and V = 0.9768(10) nm(3)).
Heated under
inert atmosphere, this compound is decomposed above 400
degrees C into
uranium phosphate-triphosphate U-2(PO4)P3O10, uranium
diphosphate
alpha-UP2O7 and diuranium oxide phosphate U2O(PO4)(2).
Crystallized
cerium (IV) phosphate-hydrogenphosphate hydrate
Ce-2(PO4)(2)(HPO4H2O)-H-. (CePHPH) was also synthesized
from
(NH4)(2)Ce(NO3)(6) and phosphoric acid Solutions by the
same method
(inonoclinic system: a = 2.1045(5) nm, b = 0.6561(2) nm,
c = 0.6949(2)
nm, beta = 91.98(1)degrees and V = 0.9588(9) nm(3)). When
heating above
600 degrees C. cerium (IV) is reduced into Ce (III) and
forms a mixture
of CePO4 (monazite structure) and CeP3O9.
2005-124
Shpanchenko, RV Lapshina, OA Antipov, EV
Hadermann, J
Kaul, EE Geibel, C
New lead vanadium phosphate with langbeinite-type structure:
Pb1.5V2(PO4)(3)
MATERIALS RESEARCH BULLETIN 40, 2005, 1569-1576.
The new lead vanadium phosphate Pb1.5V2(PO4)(3) was synthesized by
solid state reaction and characterized by X-ray powder
diffraction,
electron microscopy, and magnetic susceptibility measurements.
The
crystal structure of Pb1.5V2(PO4)(3) (a=9.78182(8) angstrom,
S.G.
P2(1)3, Z=4) was determined from X-ray powder diffraction
data and
belongs to the langbeinite-type structures. It is formed
by
corner-linked V3+O6 octahedra and tetrahedral phosphate
groups
resulting in a three-dimensional framework. The lead atoms
are situated
in the structure interstices and only partially occupy
their positions.
An electron microscopy study confirmed the structure solution.
Magnetic
susceptibility measurements revealed Curie-Weiss (CW)
behavior for
Pb1.5V2(PO4)(3) at high temperature whereas at around
14 K an abrupt
increase on the susceptibility was observed.
2005-125
Redman-Furey, N Dicks, M Bigalow-Kern, A
Cambron, RT
Lubey, G Lester, C Vaughn, D
Structural and analytical characterization of three hydrates and an
anhydrate form of risedronate
JOURNAL OF PHARMACEUTICAL SCIENCES 94, 2005, 893-911.
Four hydration states are reported for Risedronate monosodium. A
single-crystal X-ray structure determination is provided
as proof of
assignment for the monohydrate, hemi-pentahydrate, and
variable hydrate
forms. The structure provided for the anhydrate form was
determined
through simulating annealing calculations and subsequent
Reitveld
refinement of a high-quality X-ray powder diffraction
patterns
Favorable comparisons of experimentally obtained X-ray
powder patterns
are made to those generated from the single crystal data.
Characteristic infrared, Raman, and NMR spectra are provided
and
discussed for each form as are thermal analysis profiles.
In addition,
photomicrographs are provided for each of the forms isolated
for this
study. The hemi-pentahydrate is demonstrated to be the
equilibrium form
at room temperature and 37 degrees C, in the presence
of water.
2005-126
Karau, FW Schnick, W
High-pressure synthesis and X-ray powder structure determination of
the
nitridophosphate BaP2N4
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 135-141.
The novel nitridophosphate BaP2N4 was obtained by means of
high-pressure high-temperature synthesis utilizing the
multianvil
technique (8 GPa, 1400degreesC. The [PN2](-) network is
isoelectronic
with silica. The structure was solved from synchrotron
powder data by a
combination of direct methods and difference FOURIER synthesis
and
refined using the RIETVELD method (BaP2N4,Pa $$(3) over
bar, Z= 12, a =
10.22992(2) Angstrom). BaP2N4 is isotypic with BaGa2S4,
BaAl2S4 and the
high-pressure phase of CaB2O4. The (31)p solid-state NMR
yielded a
single sharp resonance at 0.4ppm.
2005-127
Chemnitzer, R Auffermann, G Tobbens, DM
Kniep, R
(Sr2N)H: On the redox-intercalation of hydrogen into Sr2N
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 1813-1817
Strontium-nitride-hydride is obtained as brown-yellow single phase
powder by reaction of strontium-subnitride (Sr2N) with
hydrogen (200
bar, 620 K) and subsequent treatment under vacuum (10(-6)
bar, 870 K).
The structure determination was carried out by a combination
of X-ray
and neutron diffraction experiments on a deuterated sample.
The
elemental composition of the ternary compound was confirmed
by means of
chemical analyses. (Sr2N)D crystallizes in the space group
R (3) over
barm with a = 381.91(2) pm and c = 1887.61(2) pm. Strontium
(Sr2+) in
the crystal structure of (Sr2N)D is arranged with an only
slightly
distorted ccp-motif. Nitrogen (N3-) and deuterium (D-)
occupy the
octahedral voids of the Sr2+ matrix in an ordered manner
resulting in
an alternating sequence of layers (anti-alpha-NaFeO2-type
structure).
2005-128
Argyriou, DN Radaelli, PG Milne, CJ
Aliouane, N Chapon, LC
Chemseddine, A Veira, J Cox, S
Mathur, ND Midgley, PA
Crystal structure of the superconducting layered cobaltate NaxCoO2
. yD(2)O
JOURNAL OF PHYSICS-CONDENSED MATTER 17, 2005, 3293-3304.
We have used electron diffraction and neutron powder diffraction to
elucidate the structural properties of superconducting
Na(x)CoO(2)(.)yD(2)O over a wide compositional range.
Our measurements
show that superconducting samples exhibit a number of
supercells
ranging from (1)/(3)a* to (1)/(15)a*, but the predominant
modulation,
observed also in the neutron data, is a double hexagonal
cell with
dimensions 2a x 2a x c. Rielveld analysis reveals that
D2O is inserted
between CoO2 sheets to form a layered network of NaO6
triangular
prisms. Our model removes the need to invoke a 5 K superconducting
point compound and suggests that a solid solution of Na
is possible
within a relatively constant amount of water y.
2005-129
Vicente, J Arcas, A Fernandez-Hernandez, JM
Sironi, A Masciocchi, N
An unprecedented process involving normal and redox transmetallation
reactions between Hg and Pt affording the unexpected
K[Pt-2{CH2C(O)Me}(6)(mu-Cl)(3)] complex: the key role
of X-ray powder
diffraction in unravelling its nature and structure
CHEMICAL COMMUNICATIONS iss 10, 2005, 1267-1269.
Hg{CH2C(O) Me}(2)] reacts with K[PtCl3(CH2LCH2)] (2 : 1 molar ratio)
to
give K[Pt-2{CH2C(O) Me}(6)(mu- Cl)(3)] ( 1); the intermediate
[Pt{CH2C(O) Me} Cl-2(CH2=CH2)](-) has been detected in
solution and
isolated as a Me4N+ salt; the process occurs through successive
normal
and redox transmetallation reactions and an ab initio
X-ray powder
diffraction study of 1 has proven to be essential to establish
its
nature.
2005-130
Wu, L Chen, XL Li, XZ Dai, L
Xu, YP Zhao, M
Synthesis and ab initio X-ray powder diffraction structure of the new
alkali and alkali earth metal borate NaCa(BO3)
ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS61,
2005, I32-I34
A sodium calcium borate, NaCaBO3, has been synthesized by the
solid-state reaction method and the structure solved from
X-ray powder
diffraction data. The compound crystallizes in space group
Pmmn and has
a desired structure type containing isolated planar BO33-
anions. Mixed
occupancy is found to exist in the Ca site, with partial
replacement by
Na. One Ca/Na mixed atom and one Na atom are at sites
with mm2
symmetry, and a second Ca/Na mixed atom, an Na atom, two
B and two O
atoms are on mirror planes.
2005-131
Dova, E Peschar, R Takata, M Nishibori,
E Schenk, H
Stassen, AF Haasnoot, JG
Low-spin state structure of [Fe(chloroethyltetrazole)(6)] (BF4)(2)
obtained from synchrotron powder diffraction data
CHEMISTRY-A EUROPEAN JOURNAL 11, 2005, 5855-5865.
The complex [Fe(teec)(6)]-(BF4)(2) (teec = chloroethyltetrazole) shows
a two-step complete spin-crossover transition in the temperature
range
300-90 K. Time-resolved synchrotron powder diffraction
experiments have
been carried out in this temperature range, and crystal.
structure
models have been obtained from the powder patterns by
using the
parallel tempering technique. Of these models, the low-spin
state
structure at 90 K has been refined completely with Rietveld
refinement.
Its structural characteristics are discussed in relation
to the
high-spin state model and other spin-crossover compounds.
The complex
shows a remarkable anisotropic unit-cell parameter contraction
that is
dependent on the applied cooling rate. In addition, the
possible
important implications for the interpretation of spin-crossover
behavior in terms of structural changes are discussed.
2005-132
Liu, XH Wankeu, MA Lucken, H Dronskowski,
R
A novel method for synthesizing crystalline copper carbodiimide, CuNCN.
Structure determination by X-ray rietveld refinement
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES
60, 2005, 593-596.
Well-crystallized copper carbodiimide, CuNCN, was synthesized by the
slow oxidation of a copper(l) cyanamide precursor under
aqueous
conditions. The X-ray powder data evidence the orthorhombic
system and
space group Cmcm with a = 2.9921(1), b = 6.1782(1), c
= 9.4003(2)
angstrom, V = 173.769(5) angstrom(3) and Z = 4. There
is a strongly
distorted octahedral Cu2+ coordination reflecting a typical
first-order
Jahn-Teller effect, with interatomic distances of 4 x
Cu-N = 2.001(2)
angstrom and 2 x Cu-N = 2.613(3) angstrom; the NCN2- unit
adopts the
carbodiimide shape with C-N = 1.227(4) A. Despite the
formal d(9)
electron count of Cu2+, CuNCN exhibits a small temperature-independent
paramagnetism and is likely to be a metallic conductor.
2005-133
Xu, HW Navrotsky, A Nyman, M Nenoff,
TM
Thermochemistry of framework titanosilicate A(2)TiSi(6)O(15) (A = K,
Rb, Cs)
JOURNAL OF THE AMERICAN CERAMIC SOCIETY 88, 2005, 1819-1825.
A new family of framework titanosilicates, A(2)TiSi(6)O(15) (A = K,
Rb,
Cs) (space group Cc), has recently been synthesized using
the
hydrothermal method. This group of phases can potentially
be utilized
for storage of radioactive elements, particularly Cs-137,
due to its
high stability under electron radiation and chemical leaching.
Here, we
report the syntheses and structures of two intermediate
members in the
series: KRbTiSi6O15 and RbCsTiSi6O15. Rietveld analysis
of powder
synchrotron X-ray diffraction data reveals that they adopt
the same
framework topology as the end-members, with no apparent
Rb/K or Rb/Cs
ordering. To study energetics of the solid solution series,
high-temperature drop-solution calorimetry using molten
2PbO .
B2O3 as the solvent at 975 K has been performed for the
end-members and
intermediate phases. As the size of the alkali cation
increases, the
measured enthalpies of formation from the constituent
oxides (Delta
H-f,ox(0)) and from the elements (Delta H-f,el(0)) become
more
exothermic, suggesting that this framework structure favors
the cation
in the sequence Cs+, Rb+, and K+. This trend is consistent
with the
higher melting temperatures of A(2)TiSi(6)O(15) phases
with increase in
the alkali cation size.
2005-134
Dikarev, EV Li, B Chernyshev, VV
Shpanchenko, RV Petrukhina, MA
Coordination polymers formed in solution and in solvent-free
environment. Structural transformation due to interstitial
solvent
removal revealed by X-ray powder diffraction
CHEMICAL COMMUNICATIONS iss 26, 2005, 3274-3276.
The crystal-to-powder transformation induced by solvent removal has
been examined through a direct comparison of the structures
of the
solvated and the unsolvated coordination products determined
by single
crystal and powder X-ray diffraction, respectively.
2005-135
Shrivastava, OP Kumar, N Sharma, IB
Synthesis, characterization and structural refinement of
polycrystalline uranium substituted zirconolite
JOURNAL OF MATERIALS SCIENCE 40, 2005, 2945-2950.
Ceramic precursors of Zirconolite (CaZrTi2O7) family have a remarkable
property of substitution on Zr4+ cationic sites. This
makes them
potential material for nuclear waste management in 'synroc'
technology.
In order to simulate the mechanism of partial substitution
of zirconium
by tetravalent actinides, a solid phase of composition
CaZr0.95U0.05Ti2O7 has been synthesized through ceramic
route by taking
calculated quantities of oxides of Ca, Ti and nitrates
of uranium and
zirconium respectively. Solid state synthesis has been
carried out by
repeated pelletizing and sintering the finely powdered
oxide mixture in
a muffle furnace at 1050 degrees C. The polycrystalline
solid phase has
been characterized by its typical powder diffraction pattern.
Step
analysis data has been used for ab initio calculation
of structural
parameters. The SEM and EDAX analysis also confirm that
zirconolite
acts as a host material for uranium. The powder diffraction
data of
3500 points between 2 theta = 10 - 80 degrees has been
analysed by GSAS
( general structure analysis system) software to obtain
the best fit of
the observed data points. The uranium substituted zirconolite
crystallizes in monoclinic symmetry with space group C2/c
(# 15). The
following unit cell parameters have been calculated: a
= 12.4883( 15),
b = 7.2448( 5), c = 11.3973( 10) and beta = 100.615( 9)degrees.
The
calculated and observed values of the intensities, lattice
parameters
and density measurement shows good agreement. The Rietveld
analysis and
GSAS based calculations for bond distance Ti-O, Ca-O,
Zr-O, and O-M-O
bond angles have been made. The structure was refined
to satisfactory
completion. The and Rp and Rwp are found to be 7.48 and
9.74 %
respectively.
2005-136 ???
Zhu, ZM Andelman, T Yin, M Chen,
TL Ehrlich, SN
O'Brien, SP Osgood, RM
Synchrotron x-ray scattering of ZnO nanorods: Periodic ordering and
lattice size
JOURNAL OF MATERIALS RESEARCH 20, 2005, 1033-1041.
We demonstrate that synchrotron x-ray powder diffraction (XRD) is a
powerful technique for Studying the structure and self-organization
of
zinc-oxide nanostructures. Zinc-oxide nanorods were prepared
by a
solution-growth method that resulted ill uniform nanorods
with 2-nm
diameter and lengths in the range 10-50 nm. These nanorods
were
structurally characterized by a combination of small-angle
and
wide-angle synchrotron XRD and transmission electron microscopy
(TEM).
Small-angle XRD and TEM were used to investigate nanorod
self-assembly
and the influence of surfactant/precursor ratio oil self-assembly.
Wide-angle XRD was used to study the evolution of nanorod
growth as a
function of synthesis time and surfactant/precursor ratio.
2005-137
Orlova, MP Kitaev, DB Spiridonova, ML
Zubkova, NV
Kabalov, YK Orlova, AI
Structure refinement of cadmium cerium(IV) phosphate Cd0.5Ce2(PO4)(3)
CRYSTALLOGRAPHY REPORTS 50, 2005, 918-922.
Cadmium cerium orthophosphate Cd0.5Ce2(PO4)(3) is synthesized by
precipitation from aqueous solutions. The structure refinement
from
powder X-ray diffraction data is preceded by the sample
preparation and
structure solution. The refinement is carried out by the
Rietveld
method (ADP-2 diffractometer, Cu-K alpha radiation, Ni
filter, 15
degrees < 2 theta < 120 degrees, 2 theta-scan step
0.02 degrees,
counting time 10 s per step). All calculations are carried
out using
the WYRIET program (version 3.3) within the sp. gr. P2(1)/n.
The
structure is refined with anisotropic displacement parameters
for
cations and isotropic displacement parameters for oxygen
atoms.
2005-138
Tobbens, DM Kahlenberg, V Kaindl, R
Characterization and ab initio XRPD structure determination of a novel
silicate with vierer single chains: The crystal structure
of NaYSi2O6
INORGANIC CHEMISTRY 44, 2005, 9554-9560.
The crystal structure of a sodium yttrium silicate with composition
NaYSi2O6 has been determined from laboratory X-ray powder
diffraction
data by simulated annealing, and has been subsequently
refined with the
Rietveld technique. The compound is monoclinic with space
group P2(1)/c
and unit cell parameters of a = 5.40787(2) angstrom, b
= 13.69784(5) A,
c = 7.58431(3) angstrom, and beta = 109.9140(3)degrees
at 23.5 degrees
C (Z = 4). The structure was found to be a single-chain
silicate with a
chain periodicity of four. The two symmetry dependent
[Si4O12] chains
in the unit cell are parallel to c. A prominent feature
is the strong
folding of the crankshaft-like chains within the b,c-plane
resulting in
intrachain Si-Si-Si angles close to 90 degrees. The coordination
of the
Y3+ ions by O2- is 7-fold in the form of slightly irregular
pentagonal
bipyramids, with oxygen atoms from four different chains
contributing
to the coordination polyhedron. Na+ ions are irregularly
coordinated by
10 oxygens from two neighboring chains. No disorder of
Na+ and Y3+
between the two nontetrahedral cation sites could be observed.
Furthermore, micro-Raman spectra have been obtained from
the
polycrystalline material.
2005-139
Parfitt, DC Keen, DA Hull, S Crichton,
WA Mezouar, M
Wilson, M Madden, PA
High-pressure forms of lithium sulphate: Structural determination and
computer simulation
PHYSICAL REVIEW B 72, 2005, 054121.
Powder x-ray diffraction has been performed on lithium sulphate,
Li2SO4, in the temperature range 300 to 1000 K and at
pressures up to
7.5 GPa. The ambient pressure beta phase appears stable
up to 3 GPa,
whereupon a slow transformation begins into a new phase,
delta-Li2SO4.
This phase is characterized by broad, very low intensity
Bragg peaks.
Above 7 GPa and with slight heating, another phase, epsilon-Li2SO4,
is
formed which shows sharp Bragg peaks. Rietveld refinement
of the
structure of the epsilon phase has shown it to be isostructural
to the
high-temperature phase III of Na2SO4. Molecular dynamics
simulations of
the epsilon phase using an established potential indicate
disordering
of the lithium ions and rotations of the sulphate groups
at high
temperature, but not at a level approaching the extreme
disordering
shown in the superionic alpha form of Li2SO4.
2005-140
Romer, SR Schnick, W
Synthesis and crystal structure determination by X-ray powder
diffraction of nickel tetrametaphosphimate octahydrate
Ni-2(PO2NH)(4) . 8 H2O
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 1749-1750.
Ni(PO2NH)(4) . 8H(2)O is isotypic with M-2(PO2NH)(4) center
dot 8 H2O (M = Mg, Mn, Co, Zn) and crystallizes in the
space group
P2(1)/c, Z = 2. with a = 641.25(l), b = 1041.42(l), c
1278.18(2) pm and
beta = 104.243(l)degrees. The structure is composed of
Ni2+ and
(PO2NH)(4)(4-) ions as well as crystal water molecules.
The P4N4 rings
of the (PO2NH)(4)(4-) ions exhibit a slightly distorted
chair-2
conformation, which has been described by torsion angles,
displacement
asymmetry parameters and Puckering parameters. The tetrametaphosphimate
anions are connected forming layers. These layers are
linked solely by
hydrogen bonds, forming a three-dimensional network.
2005-141
Brodski, V Peschar, R Schenk, H
Brinkmann, A Bloemberg, TG
van Eck, ERH Kentgens, APM
Structural analysis of a melaminium polyphosphate from X-ray powder
diffraction and solid-state NMR data
JOURNAL OF PHYSICAL CHEMISTRY B 109, 2005, 13529-13537.
The crystal structure of the environmentally friendly flame retardant
melaminium polyphosphate (MPoly)
(2,4,6-triamino-1,3,5-triazinium-PO3)(n) was determined
by a
direct-space global optimization technique from X-ray
powder
diffraction data. Solid-state NMR was used to corroborate
the proposed
hydrogen-bonding model and to determine the average degree
of
polymerization (n > 100). An analysis of the crystal structure
of MPoly
reveals aspects of molecular geometry and packing that
are
characteristic for melamine-containing compounds and polyphosphate
salts. A comparison of MPoly with the crystal structures
of its
precursors melaminium orthophosphate (MP) and melaminium
dihydrogenpyrophosphate (MPy) provides insight in the
mechanism of the
endothermic dehydration processes that takes place in
the reaction path
MP -> MPy -> MPoly. Solid-state NMR characterization of
various samples
of the same batch showed inhomogeneities in the MPoly
composition.
Various quantities of orthophosphates were found, which
cannot be
assigned to be MP.
2005-142
Hoyos, D Paillaud, JL Simon-Masseron, A
Guth, JL
Synthesis, characterization and structure determination of a
three-dimensional hydrated potassium zinc divanadate:
K[Zn2.5V2O7(OH)2] . H2O
SOLID STATE SCIENCES 7, 2005, 616-621.
K[Zn2.5V2O7(OH)(2)] . H2O was obtained by hydrothermal
synthesis at 170 degrees C from a gel with the molar composition
1
V2O5; 1 ZnCl2; 4 KOH; 228 H2O. The solid crystallizes
in the
orthorhombic system, with the space group Pnnm (58) and
with the
unit-cell parameters a = 14.5493(12) angstrom, b = 10.1685(9)
angstrom,
c = 6.0668(5) angstrom. The structure was determined from
the powder
XRD pattern by an "ab initio" method using the EXPO software
and
refined with the GSAS Rietveld refinement software. The
structure can
be described as formed from an interrupted and lacunary
oxohydroxo zinc
layers bridged by divanadate into a three-dimensional
framework. The
potassium cations and the water molecules occupy the channels
between
the bridged layers. The thermal stability, studied with
the use of TGA
and XRD, shows that the compound remains crystalline during
the
dehydration which occurs between room temperature and
210 degrees C.
2005-143
Shankland, K Kennedy, AR David, WIF
Polymorphism in tetra-aryl biphenyl diamine hole transport materials:
resolving the conflicting literature on N, N '-diphenyl-N,
N
'-bis(3,3'-methylphenyl)-1(1,1 '-biphenyl)1-4,4 '-diamine
by
high-resolution powder diffraction
JOURNAL OF MATERIALS CHEMISTRY 15, 2005, 4838-4844.
The existence of a second polymorphic form of the hole transport
material N,N'-diphenyl-N,N'-bis(3,3'-methylphenyl)-[(1,
1'-biphenyl)]-4,4'-diamine has been confirmed using both
Pawley and
Rietveld refinement of structural information against
high-resolution
synchrotron X-ray powder diffraction data.
2005-144
Mellot-Draznieks, C Serre, C Surble, S
Audebrand, N Ferey, G
Very large swelling in hybrid frameworks: A combined computational
and
powder diffraction study
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 16273-16278.
Using a combination of simulations and powder diffraction, we report
here the study of the very large swelling of a three-dimensional
nanoporous iron(III) carboxylate (MIL-88) which exhibits
almost a
reversible doubling (similar to 85%) of its cell volume
while fully
retaining its open-framework topology. The crystal structure
of the
open form of MIL-88 has been successfully refined and
indicates that
atomic displacements larger than 4 angstrom are observed
when water or
various alcohols are adsorbed in the porous structure,
revealing an
unusually flexible crystallized framework. X-ray thermodiffractometry
shows that only a displacive transition occurs during
the swelling
phenomenon, ruling out any bond breaking.
2005-145
Ferey, G Mellot-Draznieks, C Serre, C
Millange, F
Dutour, J Surble, S Margiolaki,
I
A chromium terephthalate-based solid with unusually large pore volumes
and surface area
SCIENCE 309, 2005, 2040-2042.
2005-146
Warrender, SJ Wright, PA Zhou, W
Lightfoot, P Camblor, MA
Shin, CH Kim, DJ Hong, SB
Structure of the novel large pore allosilicate TNU-7
MOLECULAR SIEVES: FROM BASIC RESEARCH TO INDUSTRIAL APPLICATIONS, PTS
A
AND B 158, 2005, 89-96.
The Structure of a novel large pore gallosilicate zcolite, TNU-7, has
been refined from X-ray powder diffraction data. The silicate
framework
is built Lip from two different types of layer which are
shown by X-ray
and electron diffraction to be arranged in a fully ordered
way. This
gives rise to 12-MR pores and asymmetric cation distributions.
TNU-7 is
prepared hydrothemally over a very narrow compositional
range and only
in the presence of Ga. Other zeolitic phases crystallise
at lower and
higher Ga contents confirming the unique structure-directing
ability of
this element. The location of ion exchanged Cs+ and Sr2+
cations in
TNU-7 has been Studied by high resolution X-ray powder
diffraction.
Warrender, SJ Wright, PA Zhou, WZ
Lightfoot, P Camblor, MA
Shin, CH Kim, DJ Hong, SB
TNU-7: A large-pore gallosilicate zeolite constructed of strictly
alternating MOR and MAZ layers
CHEMISTRY OF MATERIALS 17, 2005, 1272.
The structure solution of TNU-7 (Taejon National University number
7),
a large-pore gallosilicate zeolite constructed of strictly
alternating
MOR and MAZ layers, is presented. This "boundary phase"
zeolite was
synthesized without recourse to organic additives in a
crystallization
field surrounded by those of the structurally related
MAZ and MOR
zeolites.
2005-147
Snedden, A Charkin, DO Dolgikh, VA
Lightfoot, P
Crystal structure of the 'mixed-layer' Aurivillius phase Bi5TiNbWO15
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 180-184.
The crystal structure of the Aurivillius phase Bi5TiNbWO15 has been
analyzed in detail using powder X-ray and neutron diffraction.
The
structure can be described as a regular intergrowth of
alternating
single and double perovskite-like layers sandwiched between
fluorite-like bismuth oxide layers, such that the layer
sequence is ...
[WO4]-[Bi2O2]-[BiTiNbO7]-[Bi2O2] .... There is complete
ordering of
tungsten within the B sites of the single perovskite layer,
so that the
structure can be described as a direct intergrowth of
the 'component'
Aurivillius phases B2WO6 and Bi3TiNbO9. At 25degreesC
the structure
adopts the polar orthorhombic space group 12cm, a = 5.4231(2)
Angstrom,
b = 5.4027(2) Angstrom, c = 41.744(1)Angstrom.
2005-148
Jacob, DS Makhluf, S Brukental, I
Lavi, R Solovyov, LA Felner, I
Nowik, I Persky, R Gottlieb, HE
Gedanken, A
Sonochemical synthesis and characterization of Ni(C4H6N2)(6)(PF6)(2),
Fe(C4H6N2)(6)(BF4)(2), and Ni(C4H6N2)(6)(BF4)(2) in
1-butyl-3-methylimidazole with hexafluorophosphate and
tetrafluoroborate
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY iss 13, 2005, 2669-2677.
This paper reports on the inorganic sonochemical synthesis of
crystalline Ni(C4H6N2)(6)(PF6)(2), Fe(C4H6N2)(6)(BF4)(2),
and
Ni(C4H6N2)(6)(BF4)(2) in the ionic liquids, 1-butyl-3-methylimidazolium
hexafluorophosphate (BMI)(+)(PF6)(-) and 1-butyl-3-methylimidazolium
tetrafluoroborate (BMI)(+)(BF4)(-). The structures of
the compounds
were determined and refined by using powder X-ray diffraction
methods.
The salts crystallize in the trigonal P (3) over bar space
group. IR,
Raman and F-19 NMR spectroscopic studies confirm that
the PF6- and BF4-
anions are not bonded to the metal cations. Magnetic measurements
reveal the paramagnetic nature of the complexes. Mossbauer
investigations show that the iron atom in Fe(C4H6N2)(6)(BF4)(2)
is in
the oxidation +2 state. The broad EPR signals, which reflect
the
octahedral symmetry of the nickel complexes, were measured
for
Ni(C4H6N2)(6)(PF6)(2) and Ni(C4H6N2)(6)(BF4)(2).
2005-149
Body, M Silly, G Legein, C Buzare,
JY Calvayrac, F Blaha, P
Structural investigations of beta-CaAlF5 by coupling powder XRD, NMR,
EPR and spectroscopic parameter calculations
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 3655-3661.
beta-CaAlF5 was synthesized by solid-state reaction. The precise
structure was refined from X-ray powder diffraction data
in the
monoclinic space group P2(1)/c with lattice constants
a = 5.3361
angstrom, b = 9.8298 angstrom, c = 7.3271 angstrom, and
beta = 109.91
degrees (Z = 4). The structure exhibits isolated chains
of AlF63-
octahedra sharing opposite corners. F-19 and Al-27 solid
state NMR
spectra were recorded Using MAS and SATRAS techniques.
An EPR spectrum
was recorded for beta-CaAlF5:Cr3+. The experimental spectra
were
simulated in order to extract the NMR and EPR parameter
values. Five
fluorine sites and one low symmetry aluminium site were
found in
agreement with the refined structure.
These parameters were calculated using empirical and ab-initio
methods.
The agreement obtained between the calculated F-19 chemical
shift
values, Al-27 quadrupolar parameters, Cr3+ EPR fine structure
parameters and the experimental results demonstrates the
complementarity of XRD, magnetic resonance experiments
and theoretical
methodologies.
2005-150
Carvajal, JJ Parreu, I Sole, R Solans,
X Diaz, F Aguilo, M
Growth and structural characterization of Rb3Yb2(PO4)(3): A new
material for laser and nonlinear optical applications
CHEMISTRY OF MATERIALS 17, 2005, 6746-6754.
We report the synthesis of a new stoichiometric Yb compound,
Rb3Yb2(PO4)(3), by high-temperature solution methods.
This is the first
material of the A(3)(I)B(2)(III)((XO4)-O-V)(3) family
containing a
lanthanide element and the only one that shows optical
activity. We
resolved the structure of Rb3Yb2(PO4)(3), which crystallize
in the
cubic system, space group of symmetry I2(I)3 (a = 16.8700(10)
angstrom,
Z = 16). and studied its evolution with the temperature.
The thermal
expansion coefficient of Rb3Yb2(PO4)(3) is alpha = 8.94
x 10(-6) K-1.
This compound melts incongruently at 1450 K. The second-harmonic
generation efficiency of the Rb3Yb2-(PO4)(3), although
limited as a
result of the crystal not presenting birefringence, was
at least
similar to that of potassium dihydrogen phosphate.
2005-151
Casellas, N Gamez, P Reedijk, J
Mutikainen, I Turpeinen, U
Masciocchi, N Galli, S Sironi,
A
Moisture-triggered 1,3,5-triazine-based cull molecular switch: A
combined X-ray single-crystal and powder diffraction study
INORGANIC CHEMISTRY 44, 2005, 7918-7924.
A solvothermal synthetic procedure has been exploited to prepare the
new [Cu3L(NO3)(6)](n) coordination polymer (1) by reaction
of the
polydentate
N,N'-{2,4-di-[(di-pyridin-2-yl)amine]-1,3,5-triazine}ethylenediamine
ligand (opytrizediam Q with copper(II) nitrate. 1 has
been structurally
characterized by means of the conventional X-ray single-crystal
diffraction technique. It crystallizes in the monoclinic
C2/c space
group with a = 16.830(3), b = 20.701(4), c = 18.170(4)
angstrom, beta =
113.26(3)degrees, V= 5816(2) angstrom(3), Z = 4. 1 consists
of
trinuclear Cu3L(NO3)(5) units connected by means of a
nitrato-O,O'
bridge. The resulting chains are involved in weak interchain
head-to-tail pi-pi stacking interactions. In the presence
of moisture,
1 is readily converted into the hydrated [Cu3L(NO3)(5)](NO3)
.
H2O form (2). This second phase, monoclinic P2(1)/c, consists
of
isolated [Cu3L(NO3)(5)](+) and (NO3)(-) ions which accommodate
water
molecules in the crystal lattice. These subtle chemical
and structural
modifications accompanying the moisture-triggered 1-to-2
transformation
have been demonstrated through a X-ray powder diffraction
study. A
thermodiffractometric analysis has evidenced that this
solid-to-solid
transformation is fully reversible, i.e., thermally induced
dehydration
of 2 restores 1. The analysis of the temperature dependence
of the
magnetic susceptibility for 2 has revealed very weak ferromagnetic
interactions, consistent with the large (CuCu)-Cu-...
separation (ca.
7.5 angstrom) in the trinuclear units.
2005-152
AU Navarro, JAR Barea, E Galindo, MA
Salas, JM Romero, MA
Quiros, M Masciocchi, N Galli,
S Sironi, A Lippert, B
Soft functional polynuclear coordination compounds containing
pyrimidine bridges
JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 2436-2451.
In this account, we describe the use of simple pyrimidine derivatives
in combination with metal ions to build highly structured
molecular
architectures containing functional nanoenvironments,
cavities and
surfaces that can interact with additional species. The
supramolecular
structure of these systems can be rationally controlled
by metal
fragment geometry, reaction conditions and presence of
templating
agents. Thus, the use of transition metals with low coordination
numbers or blocked bonding positions in combination with
pyrimidines
(e.g. 2-hydroxypyrimidine, 4-hydroxypyrimidine,
2,4-dihydroxypyrimidine, 2-aminopyrimidine) leads to the
formation of
either discrete assemblies, ID polymers or helixes. When
metal ions
with higher coordination possibilities are applied instead,
2D and 3D
networks are generated. Some of the assemblies built in
this way
possess functional cavities, pores and surfaces that can
interact with
additional species by means of hydrophobic, electrostatic,
H-bonding
interactions and coordinative bonds to give rise to recognition
processes. The latter range from molecular recognition
in homogeneous
phase as well as clathrate formation, to heterogeneous
solid-gas and
solid-liquid adsorption phenomena. It should be noted
that these
materials are not rigid but able to undergo guest-induced
reorganisation processes even in the solid state. Finally,
some of
these materials also combine additional interesting magneto-optical
properties. Thus, dual systems can be envisaged in which
two or more of
these properties are present in the same material.
2005-153
Cingolani, A Galli, S Masciocchi, N
Pandolfo, L Pettinari, C Sironi, A
Sorption-desorption behavior of bispyrazolato-copper(II) 1D
coordination polymers
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 6144-6145