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1.
Jean-Claude Jumas Etienne Philippot Françoise Vermot-Gaud-Daniel M. Ribes Maurice Maurin 《Journal of solid state chemistry》1975,14(4):319-327
The crystal structure of Na4SnS4 and Ba2SnS4 (α) were determined.Na4SnS4 crystallizes in tetragonal system, space group with parameters a = 7.837 Å, c = 6.950 Å, Z = 2 and Ba2SnS4 (α) in the monoclinic system, space group with a = 8.481 Å, b = 8.526 Å, c = 12.280 Å, β = 112.97° and Z = 4.In these compounds, the crystal structure is built up from discrete orthothiostannate tetrahedra SnS4. The structure of Ba2SnS4 (α) is modified K2SO4β type. 相似文献
2.
The structure of the compound La4NiS7 has been investigated by the X-ray method. The crystal, which is tetragonal with a = 4.0801 Å and c = 16.334 Å, space group , exhibits superstructure reflections with a′ = 4a, c′ = c, and v′ = 16 v. The structure has been solved with substructure reflections (R = 0.056), the complementary structure reflections being too weak for measurement. This structure is a distorted K2NiF4 type. Lanthanum atoms are in 7–8-fold coordinated sites, one nickel atom is in a distorted octahedral site, and the other nickel atom in a site with coordinance 7. 相似文献
3.
The structure of GdPS is orthorhombic, space group Pmnb; a = 5.3620(5), b = 5.4079(6), c = 16.742(2)Å, Z = 8. It is a distorted derivative of the tetragonal PbFCl structure (a0, c0) with . The distortions are due to the formation of phosphorus chains. This structure type is found also in other rare-earth sulfopolyphosphides, e.g., with Ln = La···Sm, Tb···Tm, Y. 相似文献
4.
The compound Th0.25 NbO3 melts congruently at 1390°C. Single crystals obtained by slow cooling from the melt are transparent and show uniaxial optical properties. A single-crystal X-ray analysis confirms the tetragonal cell found by Kovba and Trunov from a powder data and gives a = 3.90 Å and c = 7.85 Å. No systematic absence of the hkl reflections is observed on precession films. The relative intensities of the main reflections are characteristic of a perovskite-like arrangement ABO3 whose large dodecahedral A sites are only partly occupied. Several domains have been found in the perovskite-type solid solution (1 ? x) Th0.25NbO3-x NaNbO3. For 0 ? x ? 0.5 the phases have a tetragonal cell with and as in pure Th0.25 NbO3. When 0.6 ? x ? 0.8 the corresponding phases crystallize with a small cubic cell (Å), while phases with 0.9 ? x ? 1 have an orthorhombic cell (). 相似文献
5.
Single crystals of the title compounds have been grown by the Czochralski technique. Pb4P2O9 crystallizes in the space group with the parameters a = 9.4812 Å, b = 7.1303 Å, c = 14.390 Å, β = 104.51° and Pb8P2O13 in with a = 10.641 Å, b = 10.206Å c = 14.342 Å, β = 98.34°. 相似文献
6.
M.T. Averbuch-Pouchot 《Journal of solid state chemistry》1978,25(4):401-402
(NH4)2HCr3AsO13 is monoclinic () with a tetramolecular unit cell: a = 13.99(1), b = 9.47(1), c = 9.55(1) Å, and β = 93.10(1)°. We describe the chemical preparation and give crystal data for this compound. 相似文献
7.
S.C. Abrahams R.C. Sherwood J.L. Bernstein K. Nassau 《Journal of solid state chemistry》1973,8(3):274-279
Three anhydrous polymorphs of cupric iodate, two hydrates, and the basic iodate salesite have been investigated. α-Cu(IO3)2 is monoclinic, space group P21, with a = 5.551 ± 0.008, b = 5.101 ± 0.004, c = 9.226 ± 0.010 Å and β = 95°4′ ± 11′, with two formulas in the unit cell. Below ΘN = 8.5 K, α-Cu(IO3)2 is antiferromagnetic and also pyroelectric. β-Cu(IO3)2 is triclinic, space group , with a = 11.230 ± 0.006, b = 11.368 ± 0.009, c = 10.630 ± 0.009 Å, α = 99°18.3′ ± 0.3′, β = 107°0.4′ ± 0.2′ and γ = 114°23.8′ ± 0.2′ and eight formulas per unit cell: the crystal is paramagnetic to 1.4K. γ-Cu(IO3)2 is monoclinic, space group , with a = 4.977 ± 0.004, b = 6.350 ± 0.004, c = 8.160 ± 0.004 Å and β = 92°20′ ± 4′, with two formulas per unit cell; γ-Cu(IO3)2 becomes antiferromagnetic below ΘN = 5 K. Cu(IO3)2·2H2O is monoclinic, space group , with a = 6.725 ± 0.005, b = 4.770 ± 0.007, c = 11.131 ± 0.013 Å and β = 103°1′ ± 4′, with two formulas per unit cell; Cu(IO3)2·2H2O is paramagnetic to 1.4 K. (mineral bellingerite) is triclinic, space group , with a = 7.197 ± 0.005, b = 7.824 ± 0.004, c = 7.904 ± 0.004 Å, α = 105°2′ ± 2′, β = 97°7′ ± 2′ and γ = 92°54′ ± 2′ with three formulas per unit cell; this crystal is paramagnetic to 1.4 K, with a moderate antiferromagnetic Cu-Cu interaction. Cu(OH)IO3 (mineral salesite) is orthorhombic, with a = 10.772 ± 0.004, b = 6.702 ± 0.002 and c = 4.769 ± 0.002 Å and four formulas per unit cell. The magnetic susceptibility indicates the possibility of antiferromagnetic ordering at 162 K; strong antiferromagnetic interactions give Θp = ?340 K. The only copper iodate studied that generates second harmonics is α-Cu(IO3)2. Indexed powder patterns are given for all six compounds. 相似文献
8.
The crystal structure of trisodium monophosphate hemihydrate was determined. The space group is and a unit cell contains eight formula units. The unit cell dimensions of are a = 9.631(3), b = 5.416(2), c = 16.938(8) Å, β = 102.60(5)°. The final R value is 0.027 for a set of 1430 independent reflections. This atomic arrangement is mainly a three-dimensional network of distorted NaO6 octahedra. The hydrogen bonding scheme is given. 相似文献
9.
Gerhard Cordier Christoph Schwidetzky Herbert Schäfer 《Journal of solid state chemistry》1984,54(1):84-88
The new compound BaSb2S4 crystallizes in the monoclinic system (space group: , No. 14) with a = 8.985(2) Å, b = 8.203(3) Å, c = 20.602(5) Å, β = 101.36(3)°. SbS3 ψ tetrahedra and ψ-trigonal SbS4 bipyramids are connected by common corners and edgers to infinite strings. These are arraged cross-wise in sheets perpendicular to the c axis. 相似文献
10.
Neutron powder profile studies show the existence of three phases in gamma uranium trioxide between 373°K and 77°K. The three phases are closely related and the transitions smooth and displacive. At 373°K, γ-UO3 is tetragonal, with a = 6.9013 (5) and c = 19.9754 (18) Å, and space group . At 323°K, γ-UO3 becomes orthorhombic, space group Fddd(D242h), with the cell dimensions (293°K) a = 9.787 (3), b = 19.932 (4) and c = 9.705 (3) Å. There is a further transition between 293°K and 77°K, and, at 77°K, the orthorhombic dimensions of the pseudocell are a = 9.8225 (7), b = 19.8487 (15), and c = 9.6318 (7) Å. The neutron diffraction studies show that, in all three phases, the coordination polyhedra of the two crystallographically distinct uranium atoms are octahedral and (dodecahedral-2) respectively. At 293°K, the shortest UO distance is 1.796 (6) Å, and thus there are no pure uranyl bonds, in agreement with the infrared spectrum. The UO distances are precise to about ± 0.006 Å, about ten times the precision of an earlier X-ray single-crystal study, in which the conclusions were in conflict with the infrared spectrum. The structure is made up of parallel chains of edge-fused U(2) octahedra, cross-linked by U(1) dodecahedra. The atomic shifts are not great in going from 373°K to 77°K; at 293°K the data will refine in the pseudotetragonal cell as well as the true orthorhombic cell, and the 77°K data will refine in the Fddd cell. 相似文献
11.
The new compound UPd2S4 was prepared by reacting stoichiometric amounts of US2, Pd, and S in evacuated quartz ampoules. UPd2S4 crystallizes in the tetragonal system, a = b = 6.734(1), c = 11.841(4)Å, space group . The crystal structure was determined from single-crystal X-ray diffraction data and refined to a conventional R factor of 0.054. Palladium has a square planar sulfur coordination with PdS distances = 2.33 Å. Uranium is coordinated with eight sulfur atoms, with a mean US distance of 2.83 Å characteristic of uranium in the tetravalent state. 相似文献
12.
β-TeVO4 crystallizes in the monoclinic system with the space group and the parameters: a = 4.379 Å, b = 13.502 Å, c = 5.446 Å, and β = 91.72°. Vanadium occupies the center of a square pyramid of oxygens, an extra oxygen is at VO = 2.77 Å. These distorted octahedra share corners forming puckered sheets parallel to (010). The sheets are held together by [Te2O6]4? groups in which tellurium is one-side coordinated by four oxygen atoms. 相似文献
13.
Marcus Vlasse Jean Claude Massies Gérard Demazeau 《Journal of solid state chemistry》1973,8(2):109-113
A precise structural refinement of ferric oxyfluoride (FeOF) has been carried out by means of singlecrystal diffraction methods. The symmetry is tetragonal, space group with a cell having dimensions: a = 4.654 ± 0.003, c = 3.058 ± 0.003 Å and containing two formula units. The structure was refined by full-matrix least squares to a conventional reliability factor of 0.032 and a weighted factor of 0.024. The structure of this compound, which is of the rutile type, is discussed. 相似文献
14.
The stoichiometric lanthanum disulfide LaS2 presents a reversible phase transition at about 750°C. The α low-temperature form is monoclinic with the LaSe2 type. All the crystals are twinned with the same twin law (100). The cell parameters are a = 8.18, b = 8.13, c = 4.03Å, γ = 90°, space group . The β high-temperature form has the orthorhombic structure previously described with the parameters a = 8.13, b = 16.34, c = 4.14 Å; space group Pnma. The two structures are compared. 相似文献
15.
Crystal structures for the fluorite-related phases CaHf4O9) and Ca6Hf19O44 () have been determined from X-ray powder diffraction data. qf1 is monoclinic, , with a = 17.698 Å, b = 14.500Å, c = 12.021 Å, β = 119.47° and Z = 16. qf2 is rhombohedral, , with a = 12.058 Å, α = 98.31° and Z = 2.Both phases are superstructures derived from the defect fluorite structure by ordering of the cations and of the anion vacancies. The ordering is such that the calcium ions are always 8-coordinated by oxygen ions, while the hafnium ions may be 6-, 7-, or 8-coordinated. The closest approach of anion vacancies is a fluorite subcell vector, and in each structure vacancies with this separation form strings. 相似文献
16.
John R. Günter 《Journal of solid state chemistry》1980,35(1):43-49
Thermal dehydration of copper(II) formate tetrahydrate leads to a modification of the anhydrous salt different from that produced by direct preparation of the latter. As the dehydration is a topotactic process, the known crystal structure of the tetrahydrate and the topotactic orientation relations can be used to deduce the crystal structure of the product. Single-crystal X-ray diffraction patterns of decomposed pseudomorphs yield the following unit cell for the dehydrated formate: monoclinic, a = 8.195 ? 0.006 Å, b = 7.925 ? 0.006 Å, c = 3.620 ? 0.005Å, β = 122.21 ? 0.09°, probable space group . The structure contains copper formate layers very similar to those in the tetrahydrate, stacked in such a way that columns of distorted coordination polyhedra, linked by formate bridges, are formed. The topotactic dehydration occurs in such a way that two-dimensional elements of the structure are unaltered but the mode of stacking is changed. 相似文献
17.
This paper gives an outline of the structure of a solid solution based on 7Bi2O3 · 2WO3. The experimental results using X-ray diffraction methods (precession and powder) showed that 7Bi2O3 · 2WO3 crystallizes in the space group with a = 12.5143(5)Å and c = 11.2248(6) Å. The number of formula weights per unit cell is 40, when the formula is considered to be of the oxygen-deficient fluorite-type Bi0.875W0.125O1.6875. The compound has a substructure based on a defect fluorite-type pseudocubic subcell with Å. The axial relations between the supercell and subcell are and . The solid solution was formed over a limited range of WO3 content between 21.3 mole% and 26.3 mole% at 700°C. The ordering of metal atoms is discussed and an ideal crystal structure is proposed. 相似文献
18.
Ninh Nguyen Jacques Choisnet Maryvonne Hervieu Bernard Raveau 《Journal of solid state chemistry》1981,39(1):120-127
Oxygen defect K2NiF4-type oxides have been synthesized for a wide composition range: 0 ≤ x ≤ 1.34. From the X-ray and electron diffraction study three domains have been characterized: orthorhombic compounds with La2CuO4 structure for 0 ≤ x < 0.10, tetragonal oxides similar to LaSrCuO4 for 0.10 ≤ x < 1 and several superstructures derived from the tetragonal cell ( with n = 3, 4, 4.5, 5, 6) for 1 ≤ x ≤ 1.34. The compounds corresponding to 0 < x < 1 differ from the other oxides in that they are characterized by the presence of copper with two oxidation states: + 2 and + 3. A model structure for La0.8Sr1.2CuλO3.4, in which copper has only the + 2 oxidation state, and for which the actual cell is tegragonal—a = 18.804 Å and c = 12.94 Å—has been established. The particular structural evolution of these compounds is discussed in terms of a competition between the capability of Cu(II) to be oxidized to Cu(III) and the ordering of oxygen vacancies. 相似文献
19.
Régnault von der Mühll Françoise Daut Jean Ravez 《Journal of solid state chemistry》1973,8(3):206-212
The crystal structure of SrFeF5 has been determined by single crystal X-ray diffraction methods.The unit cell is monoclinic (space group ) with a = 7.062 ± 0.001 Å, b = 7.289 ± 0.001 Å, c = 14.704 ± 0.001 Å, β = 95.40 ± 0.01° and Z = 8.The lattice is built up of spiral chains of octahedra parallel to the Oy axis. These chains are formed by (FeF6)3? octahedra sharing corners of the same edge. The strontium atoms bridge three neighbouring chains. The SrTiF5, SrVF5, SrCoF5, and BaInF5 phases are isostructural with SrFeF5. 相似文献
20.
Single crystals of a new oxide “FeV3O8” () have been synthesized by slowly cooling a melted mixture with the composition, 8VO2, 3V2O5, Fe2O3. The chemical formula has been determined by electron microprobe analysis. The compound, isostructural with AlNbO4 and VO2(B), has a monoclinic symmetry, space group ; the unit cell dimensions are a = 12.13Å, b = 3.679 Å, c = 6.547 Å, β = 106.85°. A structural refinement based on single crystal data has been carried out. It gave an R-factor of 1.9%. This refinement indicated that the iron and vanadium cations are partially ordered, although the average cation-oxygen distances for the two six-coordinated cations were exactly the same (1.961 Å). This conjecture was supported by the calculation of the cation valences. 相似文献