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1.
A solid solution of the GaIn3Se6 (2Ga0.5In1.5Se3) composition with a hexagonal lattice (a = 7.051(3) Å, c = 19.148(2) Å, sp. gr. P61, z = 6, V = 824.4332(4) Å3, ρ = 5.379(2) g/cm3) has been synthesized as a result of alloying Ga, In, and Se elements with a metal ratio of 1: 3. It was established that six out of nine In atoms in the lattice are located in a trigonal bipyramid, while the other three In atoms and three Ga atoms have a tetrahedral coordination. 相似文献
2.
The semimagnetic semiconductor alloy Zn0.5Mn0.5In2Te4 was refined from an X‐ray powder diffraction pattern using the Rietveld method. This compound crystallizes in the space group I42m (Nº 121), Z = 2, with unit cell parameters a = 6.1738(1) Å, c = 12.3572(4) Å, V = 471.00(2) Å3, c / a = 2.00. This material crystallizes in a stannite‐type structure. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
3.
The angular distribution of intensities of 1.003 Å neutrons scattered by an alloy of Ge0.175Te0.825 both in the amorphous and in the liquid state have been measured. The bulk amorphous sample, prepared by water quenching of the melt, has been examined at room temperature and just above the crystallization temperature Tx. The liquid sample has been examined at 400, 600 and 800°C. The analysis of the structure factors obtained from the corrected and scaled intensities indicates that the structural features of the amorphous sample are similar to those which would be expected if it were possible to cool the alloy to room temperature, while maintaining it in the liquid state. The analysis of the radical distribution functions, from Fourier inversion of the structure factors, indicates that a change of the coordination number n1 from 2.43 to 3.25 occurs in passing from the amorphous to the liquid state at 400°C. This result has been interpreted in terms of coordination models. In the liquid state, it has been found that a model with fourfold coordinated Ge and threefold coordinated Te is consistent with n1=3.25. The internal consistency of this model for the liquid state allows us to make a reasonable choice between the possibility of a 3 or 4 fold coordination for Ge in the glass. We conclude that a model based on four-fold coordinated Ge and twofold coordinated Te seems an appropriate representation for the coordination of the amorphous material. 相似文献
4.
I. O. Troyanchuk M. K. Karpuk O. S. Mantytskaya H. Szymczak 《Crystallography Reports》2004,49(4):626-630
Perovskites Bi0.5D0.5MnO3(D = Pb, Ba) were prepared under high pressure (4 GPa) at 1200–1300°C. According to the X-ray diffraction data, crystalline Bi0.5Pb0.5MnO3 has a tetragonal unit cell with the parameters a = 3.940 Å and c = 3.800 Å, whereas Bi0.5Ba0.5MnO3 crystals are cubic with a = 3.940 Å. It is concluded from magnetic studies that lead-containing manganite is an antiferromagnet with TN = 120 K, whereas Bi0.5Ba0.5MnO3 is a spin glass with spin-freezing temperature T f = 38 K. Both compounds are decomposed upon heating in air at temperatures above 500°C. With the use of synthesis in air, Bi0.5Ca0.5 ? xD x MnO3 solid solutions with x as high as 0.25 were obtained. 相似文献
5.
Noël Lugan Jean -Michel Savariault Guy Lavigne Jean -Jacques Bonnet 《Journal of chemical crystallography》1983,13(6):389-405
The title compound is (μ-H)Ru3(CO)7(μ-As(C6H5)CH2As(C6H5)2)((C6H5)2 AsCH2As(C6H5)2)·CH2C12. Crystal data: monoclinic,P21/n, cell parameters (X-ray)a=12.82(2) Å,b=22.91(2) Å,c=17.83(2) Å, β=99.1(3)°; (neutron)a=12.94(1) Å, β=22.95(2)Å,c=17.93(3)Å,β=99.55(5)°. The structure was solved from X-ray data. FinalR indices areR(F)=0.051,R w (F)=0.049 (X-ray);R(F)=0.064,R w (F)=0.048,R(F 2)=0.072,R w (F2)=0.088 (neutron). The complex is derived from Ru3(CO)8(dpam)2 through reaction with hydrogen. The structure consists of a triangular array of metal atoms involving three metal-metal bonds[Ru(1)?Ru(2)=2.912(7)Å;Ru(1)?Ru(3)=2.829(3) A; Ru(2)?Ru(3)=2.845(6) Å]. The metal-metal edge Ru(1)?Ru(2) is supported by a bridging bis(diphenylarsino)methane ligand which lies in the equatorial plane. Activation of the second dpam ligand has generated the new face-bridging ligand unit μ-As(C6H5)CH2As(C6H5)2. In this unit, the bridgehead As atom spans over the Ru(1)?Ru(2) bond, while the second As atom is only bonded to Ru(3). The metal environment is achieved by CO ligands. The hydride ligand is bridging the Ru(1)?Ru(2) vector [Ru(1)?H=1.791(10) Å; Ru(2)?H=1.818(8) Å]. Geometric features of the dibridged Ru(μ-H)(μ-As)Ru bond are discussed. 相似文献
6.
A theory of the structural phase transition in LiZn0.5Mn1.5O4 cathode material is proposed. The symmetry of the order parameter, thermodynamics, and mechanisms of formation of the atomic structure of low-symmetry ordered cubic lithium-zinc-manganese oxide spinel have been studied. The critical order parameter inducing the phase transition has been found. It is shown that the calculated LiZn0.5Mn1.5O4 structure is formed due to displacements and orderings of lithium, zinc, manganese, and oxygen atoms. Within the Landau theory of phase transitions, it is shown that the phase states may change from high-symmetry cubic disordered Fd3m phase to the low-symmetry ordered cubic P213 phase as a result of first-order phase transitions. 相似文献
7.
B. A. Maksimov S. S. Kazantsev V. N. Molchanov I. A. Verin B. V. Mill 《Crystallography Reports》2004,49(4):585-590
The crystal structure of monoclinic La3SbZn3Ge2O14 crystals from the langasite family is determined by X-ray diffraction analysis [a = 5.202(1) Å, b = 8.312(1) Å, c = 14.394(2) Å, β = 90.02(1)°, sp. gr. A2, Z = 2, and R/R w = (5.2/4.6)%]. The structure is a derivative of the Ca3Ga2Ge4O14-type structure (a = 8.069 Å, c = 4.967 Å, sp. gr. P321, Z = 1). The crystal studied is a polysynthetic twin with the twin index n = 2, whose monoclinic components are related by pseudomerohedry by a threefold rotation axis of the supergroup P321. 相似文献
8.
V. I. Pet’kov A. I. Orlova G. I. Dorokhova Ya. V. Fedotova 《Crystallography Reports》2000,45(1):30-34
Double zirconium and 3d-transition metal phosphates of the compositions M 0.5Zr2(PO4)3[M = Mn (I), Co (II), Ni (III), Cu (IV), Zn (V)] have been synthesized and the types of their structures have been refined. Compounds I, II, III, IV, and V are all monoclinic (sp. gr. P21/n, Z = 4) and have the unit cell parameters a = 12.390(3), 12.389(3), 12.385(3), 12.389(3), 12.389(2) Å; b = 8.931(4), 8.928(3), 8.924(4), 8.925(4), 8.929(3) Å; c = 8.843(3), 8.840(2), 8.840(3), 8.841(3), 8.842(2) Å, β = 90.55(1), 90.54(1), 90.53(1), 90.53(1), 90.54(1)°; V = 978.5, 977.7, 977.0, 977.4, 978.1 Å3, respectively. All the structures have the {[Zr2(PO4)3]?}3∞-type frameworks. The crystallographic data for 3d-transition and alkali earth metal phosphates described by the general formula M 0.5Zr2(PO4)3 are compared. 相似文献
9.
Crystal structure of the double magnesium zirconium orthophosphate at temperatures of 298 and 1023 K
E. R. Gobechiya M. V. Sukhanov V. I. Pet’kov Yu. K. Kabalov 《Crystallography Reports》2008,53(1):53-59
Double magnesium zirconium orthophosphate Mg0.5Zr2(PO4)3 is synthesized by the sol-gel method. The compound prepared is characterized using electron probe microanalysis and X-ray diffraction. The crystal structure of the orthophosphate is refined by the Rietveld method in space group P21/n (Z = 4) at temperatures of 298 K [a = 12.4218(2) Å, b = 8.9025(2) Å, c = 8.8218(2) Å, β = 90.466(1)°] and 1023 K [a = 12.4273(5) Å, b = 8.9453(4) Å, c = 8.8405(4) Å, β = 90.320(3)°]. It is demonstrated that an increase in the temperature leads to an anisotropic expansion of the unit cell of the phosphate structure, but the structural type remains unchanged. 相似文献
10.
An accurate X-ray diffraction study of an La3Ta0.25Ga5.25Si0.5O14 single crystal has been performed using two data sets obtained independently for the same sample in different orientations on a diffractometer with a 2D CCD detector. This structure was refined with an averaged set of these data (a = 8.1936(15) Å c = 5.1114(6) Å, sp. gr. P321, Z = 1, R/wR = 0.75/0.71%, 4030 independent reflections). This analysis was aimed at determining the character of the occupancies of the cation position in the structure. The octahedra at the origin of coordinates turned out to be statistically occupied by gallium and tantalum ions of similar sizes, whereas the tetrahedra on the threefold symmetry axes are occupied by gallium and silicon whose ionic radii differ significantly. The latter circumstance caused the splitting of oxygen positions and made it possible to reliably establish the structural position of statistically located [SiO4] and [GaO4] tetrahedra of different sizes. 相似文献
11.
The structure of the semiconducting alloy Cu2Cd0.5Mn0.5GeSe4 was refined from an X‐ray powder diffraction pattern using the Rietveld method. The present alloy crystallizes in the wurtz‐stannite structure, space group Pmn21 (No 31), and unit cell parameters values of a = 8.0253(2) Å, b = 6.8591(2) Å, c = 6.5734(2) Å and V = 361.84(2) Å3. The structure exhibits a three‐dimensional arrangement of slightly distorted CuSe4, Cd(Mn)Se4 and GeSe4 tetrahedras connected by corners. © 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim 相似文献
12.
N. E. Zhukhlistova 《Crystallography Reports》2002,47(3):433-442
The crystal structure of the complex of enniatin B, cyclo[-(L-MeVal-D-Hyi)3-](C33H57N3O9), with KNCS is determined by X-ray diffraction [CuKαradiation, R = 0.0594 for 7925 reflections with I > 2 σ(I)]. The crystals belong to the space group P3, a = 24.448(5) Å, c = 23.578(5) Å, V = 12277(9) Å3, and Z = 6. The unit cell contains 12 symmetrically independent molecules of the antibiotic, which are located on crystallographic threefold axes. The K+ ions are located on the threefold axes and are coordinated by the carbonyl oxygen atoms of the hydroxy acid or amino acid residues of the enniatin molecules to form prisms, twisted prisms, and antiprisms. All the independent enniatin molecules retain the principal conformational features revealed earlier in the structures of enniatin B and its complexes. 相似文献
13.
A lanthanum coordination polymer, [La(2,5-PZDC)1.5(H2O)] n , (2,5-PZDC = 2,5-pyrazinedicarboxylate) has been synthesized by using the reaction of LaCl3?7H2O with 2,5-pyrazinedicarboxylic acid under hydrothermal condition and structurally characterized by X-ray diffraction method. It crystallizes in the triclinic system P \(\bar 1\) with a = 6.297(2) Å, b = 6.762(2) Å, c = 13.450(4) Å, α = 82.984(5)°, β = 83.164(5)°, γ = 63.260(4)°, V = 506.3(3) Å3, Z = 2. The La3+ ion is nine-coordinate in a N2O7 environment, with a tricapped trigonal prism geometry, and the ligand 2,5-pyrazinedicarboxylate adopts two coordination modes, through which lanthanum ions are linked together to form a three-dimensional structure. 相似文献
14.
The crystal structure of 3-ammonium-4-hydroxyphenyl sulfonate hemihydrate C6H3(NH3)(OH)SO3 · 0.5H2O is determined by single-crystal X-ray diffraction. The unit cell parameters are as follows: a = 11.2395(3), b = 10.3814(3), c = 13.7509(4) Å, β = 100.326(1)°, V = 1578.49(8) Å3, space group P21/n, Z = 4. The crystal structure can be described us a succession of infinite corrugated layers parallel to ab plane. These layers consist of rings formed by four sulfonate molecules located around a center of symmetry. The rings are connected to each other and to water molecules via O-H...O hydrogen bonds. The structure is further stabilized by π-π interactions between phenyl rings of organic entities of successive layers. 相似文献
15.
G. B. Andreev M. Yu. Antipin A. M. Fedoseev N. A. Budantseva 《Crystallography Reports》2001,46(3):383-384
The crystal structure of the hexavalent neptunium complex NpO2CrO4 · 2[OC(NH2)2] is determined. The crystal data are a = 7.192(2) Å, b = 12.902(4) Å, c = 11.226(3) Å, β = 92.19(2)°, V = 1040.9(4) Å3, space group P21/n, Z = 4, d calcd = 3.223 g/cm3, R = 0.045, and R w = 0.130. The coordination polyhedron of the Np atom is the pentagonal bipyramid whose equatorial plane is formed by the oxygen atoms of the chromate ions and carbamide molecules. 相似文献
16.
A. A. Pugacheva B. A. Maksimov B. V. Mill’ Yu. V. Pisarevskii D. F. Kondakov T. S. Chernaya I. A. Verin V. N. Molchanov V. I. Simonov 《Crystallography Reports》2004,49(1):53-59
The complete X-ray structure determination of Czochralski grown La3Zr0.5Ga5Si0.5O14 single crystals with the Ca3Ga2Ge4O14 structure is performed (sp. gr. P321, a = 8.226(1) Å, c = 5.1374(6) Å, Z = 1, Mo Kα1 radiation, 1920 crystallographically independent reflections, R = 0.0166, Rw = 0.0192). The absolute structure is determined. It is shown that possible transition of some of La atoms (~1.2%) from the 3e to 6g position may give rise to the formation of structural defects. 相似文献
17.
N. A. Budantseva G. B. Andreev A. M. Fedoseev M. Yu. Antipin J.-C. Krupa 《Crystallography Reports》2003,48(1):58-60
The crystal structure of the [NpO2(NO3)(Terpy)(H2O)] complex between pentavalent neptunium and 2,2′,6′,2″-terpyridine is determined. The crystal data are as follows: a = 11.130(3) Å, b = 7.916(2) Å, c = 18.324(5) Å, β = 100.873(6)°, V = 1585.5(8) Å3, Z = 4, space group is P21/n, R = 0.044, and wR(F 2) = 0.092. The coordination polyhedron of the Np atom is a pentagonal bipyramid whose equatorial plane includes three nitrogen atoms of the Terpy molecule and two oxygen atoms of the nitrate ion and the water molecule. 相似文献
18.
N. B. Bolotina R. K. Rastsvetaeva A. N. Sapozhnikov A. A. Kashaev A. Schöenleber G. Chapuis 《Crystallography Reports》2003,48(1):8-11
The three-dimensionally modulated incommensurate crystal structure of lazurite from the Baikal region was determined for the first time. The structure was solved within the cubic system with the unit-cell parameter a cub = 9.077(1) Å and the (3+2)-dimensional superspace group Pnn2 (q 1, q 2) under the assumption of a twin model consisting of three orthorhombic components related by a threefold axis along the [111] direction. The structure was refined using 257 main reflections and 2392 first-order satellite reflections with the isotropic thermal parameters to wR 0 = 1.98% and wR 1 = 7.50% respectively. 相似文献
19.
At room temperature, a new coordination polymer [Ni(tpt)(imi)3(H2O)]n was synthesized by the reaction of NiCl2?6H2O, terephthalic acid, and imidazole in aqueous solution. The structure was determined by X-ray crystallography. It crystallizes in monoclinicP21/n space group with the crystal cell parameters ofa = 9.8626(4) Å,b = 15.2498(3) Å, andc = 12.7681(3)Å, β = 90.309(2)°,V = 1920.33(10) Å3, andZ = 4. The crystal X-ray analysis shows that each nickel atom is coordinated by three imidazole ligands, two terephthalate ions, and one water molecule. Each terephthalate ion bridges two nickel atoms to form a zigzag chain. The chains are further linked together via hydrogen bonds to a three-dimensional network. 相似文献
20.
N. B. Bolotina R. K. Rastsvetaeva A. N. Sapozhnikov A. A. Kashaev A. Shönleber G. Chapuis 《Crystallography Reports》2003,48(5):721-727
The incommensurately modulated structure of isotropic lazurite (the Baikal region) was established for the first time. The structure was solved within a pseudocubic unit cell with the parameter a = 9.077(1) Å and the (3 + 2)-dimensional superspace group Pnn2(γγ0, γ-g0) based on a twin model consisting of three two-dimensionally modulated orthorhombic components related by a threefold axis along the [111] direction. The structure was refined with isotropic thermal parameters to wR0 = 1.98% and wR1 = 7.5% using 257 main reflections and 2392 first-order satellite reflections, respectively. 相似文献