scholarly journals Syntheses and crystal structures of the quaternary thiogermanates Cu4FeGe2S7 and Cu4CoGe2S7

2020 ◽  
Vol 76 (7) ◽  
pp. 1117-1121 ◽  
Author(s):  
Andrew J. Craig ◽  
Stanislav S. Stoyko ◽  
Allyson Bonnoni ◽  
Jennifer A. Aitken
Keyword(s):  
Three Dimensional ◽  
Structure Type ◽  
Polar Space ◽  
Fused Silica ◽  
Powder Diffraction Data ◽  
Reaction Products ◽  
Framework Structure ◽  
X Ray ◽  
Melting Temperatures ◽  
Sulfide Ions

The quaternary thiogermanates Cu4FeGe2S7 (tetracopper iron digermanium heptasulfide) and Cu4CoGe2S7 (tetracopper cobalt digermanium heptasulfide) were prepared in evacuated fused-silica ampoules via high-temperature, solid-state synthesis using stoichiometric amounts of the elements at 1273 K. These isostructural compounds crystallize in the Cu4NiSi2S7 structure type, which can be considered as a superstructure of cubic diamond or sphalerite. The monovalent (Cu+), divalent (Fe2+ or Co2+) and tetravalent (Ge4+) cations adopt tetrahedral geometries, each being surrounded by four S2− anions. The divalent cation and one of the sulfide ions lie on crystallographic twofold axes. These tetrahedra share corners to create a three-dimensional framework structure. All of the tetrahedra align along the same crystallographic direction, rendering the structure non-centrosymmetric and polar (space group C2). Analysis of X-ray powder diffraction data revealed that the structures are the major phase of the reaction products. Thermal analysis indicated relatively high melting temperatures, near 1273 K.

scholarly journals Reinvestigation of trilithium divanadium(III) tris(orthophosphate), Li3V2(PO4)3, based on single-crystal X-ray data

2013 ◽  
Vol 69 (2) ◽  
pp. i11-i12 ◽  
Author(s):  
Yongho Kee ◽  
Hoseop Yun
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Title Compound ◽  
Three Dimensional ◽  
Structure Type ◽  
Powder Diffraction Data ◽  
Charge Balance ◽  
X Ray ◽  
Anisotropic Displacement Parameters

The structure of Li3V2(PO4)3has been reinvestigated from single-crystal X-ray data. Although the results of the previous studies (all based on powder diffraction data) are comparable with our redetermination, all atoms were refined with anisotropic displacement parameters in the current study, and the resulting bond lengths are more accurate than those determined from powder diffraction data. The title compound adopts the Li3Fe2(PO4)3structure type. The structure is composed of VO6octahedra and PO4tetrahedra by sharing O atoms to form the three-dimensional anionic framework∞3[V2(PO4)3]3−. The positions of the Li+ions in the empty channels can vary depending on the synthetic conditions. Bond-valence-sum calculations showed structures that are similar to the results of the present study seem to be more stable compared with others. The classical charge balance of the title compound can be represented as [Li+]3[V3+]2[P5+]3[O2−]12.

scholarly journals Crystal structure of barium perchlorate anhydrate, Ba(ClO4)2, from laboratory X-ray powder data

2015 ◽  
Vol 71 (6) ◽  
pp. 588-591 ◽  
Author(s):  
Jeonghoo H. Lee ◽  
Ji Hoon Kang ◽  
Sung-Chul Lim ◽  
Seung-Tae Hong
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Structure Type ◽  
Site Symmetry ◽  
Powder Diffraction Data ◽  
Asymmetric Unit ◽  
Orthorhombic Space Group ◽  
Special Position ◽  
X Ray ◽  
Barium Perchlorate

The previously unknown crystal structure of barium perchlorate anhydrate, determined and refined from laboratory X-ray powder diffraction data, represents a new structure type. The title compound was obtained by heating hydrated barium perchlorate [Ba(ClO4)2·xH2O] at 423 Kin vacuofor 6 h. It crystallizes in the orthorhombic space groupFddd. The asymmetric unit contains one Ba (site symmetry 222 on special position 8a), one Cl (site symmetry 2 on special position 16f) and two O sites (on general positions 32h). The structure can be described as a three-dimensional polyhedral network resulting from the corner- and edge-sharing of BaO12polyhedra and ClO4tetrahedra. Each BaO12polyhedron shares corners with eight ClO4tetrahedra, and edges with two ClO4tetrahedra. Each ClO4tetrahedron shares corners with four BaO12polyhedra, and an edge with the other BaO12polyhedron.

Crystal structures of tricalcium citrates

2018 ◽  
Vol 33 (2) ◽  
pp. 98-107 ◽  
Author(s):  
James A. Kaduk
Keyword(s):  
Crystal Structures ◽  
Density Functional ◽  
Three Dimensional ◽  
Water Molecules ◽  
Calcium Citrate ◽  
Powder Diffraction Data ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Calcium Supplements ◽  
Dimensional Network

The crystal structures of calcium citrate hexahydrate, calcium citrate tetrahydrate, and anhydrous calcium citrate have been solved using laboratory and synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Both the hexahydrate and tetrahydrate structures are characterized by layers of edge-sharing Ca coordination polyhedra, including triply chelated Ca. An additional isolated Ca is coordinated by water molecules, and two uncoordinated water molecules occur in the hexahydrate structure. The previously reported polymorph of the tetrahydrate contains the same layers, but only two H2O coordinated to the isolated Ca and two uncoordinated water molecules. Anhydrous calcium citrate has a three-dimensional network structure of Ca coordination polyhedra. The new polymorph of calcium citrate tetrahydrate is the major crystalline phase in several commercial calcium supplements.

Ab initio structure determination of nanosized θ-KAlF4 with edge-sharing AlF6 octahedra

2009 ◽  
Vol 24 (3) ◽  
pp. 185-190 ◽  
Author(s):  
A. Le Bail
Keyword(s):  
Crystal Structure ◽  
Ab Initio ◽  
Fluorite Structure ◽  
Structure Type ◽  
Powder Diffraction Data ◽  
Orthorhombic Unit Cell ◽  
Common Edge ◽  
X Ray ◽  
Ab Initio Structure

θ-KAlF4 is a new nanosized potassium tetrafluoroaluminate metastable polymorph (13×18×55 nm3). The crystal structure is solved ab initio from X-ray powder diffraction data in direct space [orthorhombic unit cell with a=8.3242(3) Å, b=7.2502(3) Å, c=11.8875(4) Å, V=717.44(5) Å3, Z=8, and space group Pnma]. This new structure type, unique in the whole AIMIIIF4 family, is related to the fluorite structure and consists of AlF6 octahedra linked via a common edge forming a bioctahedral motif which is trans-connected through the corner-shared fluorine, resulting in the formation of infinite ladderlike double file of octahedra ([Al2F8]2−)n running along the b axis.

M3+(H2AsO4)(H2As2O7) (M3+= Al, Ga) and In2(H2AsO4)2(H2As2O7)2: a new layer structure type and a new framework structure type containing the rare H2As2O72−group

2017 ◽  
Vol 73 (8) ◽  
pp. 600-608 ◽  
Author(s):  
Karolina Schwendtner ◽  
Uwe Kolitsch
Keyword(s):  
Hydrogen Bonds ◽  
Room Temperature ◽  
Layer Structure ◽  
Structure Type ◽  
Three Dimensions ◽  
Framework Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Third ◽  
New Framework

The crystal structures of hydrothermally synthesized aluminium dihydrogen arsenate(V) dihydrogen diarsenate(V), Al(H2AsO4)(H2As2O7), gallium dihydrogen arsenate(V) dihydrogen diarsenate(V), Ga(H2AsO4)(H2As2O7), and diindium bis[dihydrogen arsenate(V)] bis[dihydrogen diarsenate(V)], In2(H2AsO4)2(H2As2O7)2, were determined from single-crystal X-ray diffraction data collected at room temperature. The first two compounds are representatives of a novel sheet structure type, whereas the third compound crystallizes in a novel framework structure. In all three structures, the basic building units areM3+O6octahedra (M= Al, Ga, In) that are connectedviaone H2AsO4−and two H2As2O72−groups into chains, and furtherviaH2As2O72−groups into layers. In Al/Ga(H2AsO4)(H2As2O7), these layers are interconnected by weak-to-medium–strong hydrogen bonds. In In2(H2AsO4)2(H2As2O7)2, the H2As2O72−groups link the chains in three dimensions, thus creating a framework topology, which is reinforced by weak-to-medium–strong hydrogen bonds. The three title arsenates represent the first compounds containing both H2AsO4−and H2As2O72−groups.

Crystal structure of (Z)-cefprozil monohydrate, C18H19N3O5S(H2O)

2019 ◽  
Vol 34 (4) ◽  
pp. 379-388
Author(s):  
Zachary R. Butler ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Density Functional ◽  
Three Dimensional ◽  
Ion Pair ◽  
Powder Diffraction Data ◽  
Powder Diffraction File ◽  
X Ray ◽  
Dimensional Network ◽  
Acid Proton

The crystal structure of cefprozil monohydrate has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Cefprozil monohydrate crystallizes in space group P21 (#4) with a = 11.26513(6), b = 11.34004(5), c = 14.72649(11) Å, β = 90.1250(4)°, V = 1881.262(15) Å3, and Z = 4. Although a reasonable fit was obtained using an orthorhombic model, closer examination showed that many peaks were split and/or had shoulders, and thus the true symmetry was monoclinic. DFT calculations revealed that one carboxylic acid proton moved to an amino group. The structure thus contains one ion pair and one pair of neutral molecules. This protonation was confirmed by infrared spectroscopy. There is an extensive array of hydrogen bonds resulting in a three-dimensional network. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.

X-Ray Powder Diffraction Data and Crystal Refinement of Ternary Compound Ti4ZrSi3

2020 ◽  
Vol 841 ◽  
pp. 99-102
Author(s):  
Liu Qing Liang ◽  
Yan Ying Wei ◽  
De Gui Li
Keyword(s):  
Ternary Compound ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Structure Type ◽  
Hexagonal Structure ◽  
Powder Diffraction Data ◽  
Tungsten Electrode ◽  
X Ray

Ternary compound Ti4ZrSi3 was prepared by arc melting using a non-consumable tungsten electrode under argon atmosphere, then annealed at 1023K for 30 days, the X-ray powder diffraction data of Ti4ZrSi3 was collected on a Rigaku SmartLab X-ray powder diffractometer. The powder patterns of the compound were indexed and structure refinement by using Rietveld method indicate that the Ti4ZrSi3 compound crystallizes in the hexagonal structure, space group P6/mcm (No.193) with Mn5Si3 structure type, a=b=7.5759(3) Ǻ, c=5.2162(2) Ǻ, V=259.28Ǻ3, Z=2, ρx=4.779g cm-3, the Smith–Snyder FOM F30=148.7(0.0064, 46) and the intensity ratio RIR=1.37. The Rietveld refinement results were Rp = 0.0836, Rwp= 0.1092.

Anti-KSbF6 structure of CaTbF6 and CdTbF6: a confirmation of the singular crystal chemistry of Tb4+ in fluorides

2005 ◽  
Vol 61 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Michaël Josse ◽  
Marc Dubois ◽  
Malika El-Ghozzi ◽  
Joël Cellier ◽  
Daniel Avignant
Keyword(s):  
Crystal Structures ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Neutron Powder Diffraction ◽  
Fluoride Ion ◽  
Crystal Chemical ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Neutron Powder Diffraction Data ◽  
Simple Cubic

The crystal structures of two new tetravalent terbium fluorides, CaTbF6 and CdTbF6, have been determined from X-ray and neutron powder diffraction data. The title compounds exhibit an anti-KSbF6 structure, the three-dimensional framework of which is built of [TbF6]2− chains of edge-sharing dodecahedra further linked, by sharing corners, to isolated [MF6]4− octahedra (M = Ca, Cd). The mechanism of the anionic sublattice rearrangement when going from KSbF6 to CaTbF6 is described and related to a simple cubic fluoride-ion packing. Comparison with the crystal structures of β-BaTbF6 and other representatives of the M II M^{\prime \rm IV}F6 family allows the singular crystal-chemical properties of some fluoroterbates to be emphasized.

An arsenate with the α-CrPO4 structure type, NaCa1–x Ni3–2x Al2x (AsO4)3 (x = 0.23): crystal structure, charge-distribution and bond-valence-sum analyses

2017 ◽  
Vol 73 (11) ◽  
pp. 896-904 ◽  
Author(s):  
Ridha Ben Smail ◽  
Mohamed Faouzi Zid
Keyword(s):  
Crystal Structure ◽  
Charge Distribution ◽  
Structural Model ◽  
Ionic Conduction ◽  
Three Dimensional ◽  
Structure Type ◽  
Bond Valence ◽  
Ion Conductor ◽  
X Ray ◽  
Bond Valence Sum

Since the discovery of electrochemically active LiFePO4, materials with tunnel and layered structures built up of transition metals and polyanions have become the subject of much research. A new quaternary arsenate, sodium calcium trinickel aluminium triarsenate, NaCa1–x Ni3–2x Al2x (AsO4)3 (x = 0.23), was synthesized using the flux method in air at 1023 K and its crystal structure was determined from single-crystal X-ray diffraction (XRD) data. This material was also characterized by qualitative energy-dispersive X-ray spectroscopy (EDS) analysis and IR spectroscopy. The crystal structure belongs to the α-CrPO4 type with the space group Imma. The structure is described as a three-dimensional framework built up of corner-edge-sharing NiO6, (Ni,Al)O6 and AsO4 polyhedra, with channels running along the [100] and [010] directions, in which the sodium and calcium cations are located. The proposed structural model has been validated by bond-valence-sum (BVS) and charge-distribution (CHARDI) tools. The sodium ionic conduction pathways in the anionic framework were investigated by means of the bond-valence site energy (BVSE) model, which predicted that the studied material will probably be a very poor Na+ ion conductor (bond-valence activation energy ∼7 eV).

Powder diffraction data of a new compound Al0.35GdGe2

2008 ◽  
Vol 23 (1) ◽  
pp. 60-62 ◽  
Author(s):  
Lingmin Zeng ◽  
Jiejun He ◽  
Pingli Qin ◽  
Xiangzhong Wei
Keyword(s):  
Ternary Compound ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Type ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
Type Space

A new ternary compound Al0.35GdGe2 has been synthesized and studied by means of X-ray powder diffraction technique. The ternary compound Al0.35GdGe2 crystallizes in the orthorhombicwith the CeNiSi2 structure type (space group Cmcm, a=4.0874(2) Å, b=16.1499(5) Å,c=3.9372(1) Å, Z=4, and Dcalc=8.007 g/cm3).

Sign in / Sign up

Export Citation Format

Share Document