Strukturvarianten des MgCu2-Typs: Die Verbindungen Mg2Ni3P und Mg2Ni3As / Variants of the MgCu2 Type: The Compounds Mg2Ni3P and Mg2Ni3As

1992 ◽  
Vol 47 (10) ◽  
pp. 1351-1354 ◽  
Author(s):  
Viktor Keimes ◽  
Albrecht Mewis
Keyword(s):  
Single Crystal ◽  
Homogeneity Range ◽  
Hexagonal Lattice ◽  
Structure Type ◽  
Type Structure ◽  
X Ray ◽  
Lattice Constants ◽  
Metal Atoms ◽  
Rhombohedral Symmetry

The compounds Mg2Ni3P and Mg2Ni3As were prepared by heating the elements. Their structures have been determined from single-crystal X-ray data. The structure of the phosphide is a rhombohedral ternary variant of the cubic Laves structure type MgCu2 (R 3̄ m; hexagonal lattice constants: a = 4.971(0) Å, c = 10.961(2) Å). The ordered substitution of one quarter of the metal atoms by phosphorus and the resulting shorter distances are responsible for the rhombohedral symmetry.The arsenide crystallizes in the MgCu2 type structure (Fd 3 m; a = 6.891(1)A, composition Mg2Ni3As) with a statistic distribution of the Ni and As atoms; the relevant homogeneity range extends from Mg2Ni2.9As1.1 to Mg2Ni3.5As0.5.

The Crystal Structures of Re2Al, Re4Al11, and ReAl6

1993 ◽  
Vol 48 (12) ◽  
pp. 1767-1773 ◽  
Author(s):  
Sabine Niemann ◽  
Wolfgang Jeitschko
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Type Structure ◽  
Variable Parameters ◽  
X Ray ◽  
Lattice Constants ◽  
Structure Factors ◽  
Pauli Paramagnetism

Well-crystallized samples of the rhenium aluminides Re4Al11 and ReAl6 were obtained by reaction of rhenium with an excess of aluminum. Re4Al11 was found to be isotypic with Mn4Al11. The MnAl6 type structure of ReAl6 was confirmed. The crystal structures of both compounds were refined from single-crystal X-ray data. Re4Al11:P1̄, Z = 1, a = 516.0(1) pm, b = 896.3(2) pm, c = 516.9(1) pm, a = 90.44(1)°, β = 99.76(1)°, γ = 105.17(1)°, V = 0.2271 nm3, R = 0.036 for 2315 structure factors and 74 variable parameters. ReAl6: Cmcm, Z = 4, a = 761.0(1) pm, b = 660.5(1) pm, c = 903.4(1) pm, V = 0.4541 nm3, R = 0.013 for 711F values and 23 variables. In both structures the rhenium atoms have ten aluminum neighbors at distances from 245 to 277 pm. The Al-Al distances cover the whole range from 251 to 362 pm rather continuously. The previously reported compound Re2Al with the tetragonal MoSi2-type structure has the lattice constants a = 298.1(1) pm, c = 958.4(4) pm, V = 0.08519 nm3. ReAl6 shows Pauli-paramagnetism.

Rh2Sb with (anti-)PbCl2-Type Structure

1990 ◽  
Vol 45 (7) ◽  
pp. 947-951 ◽  
Author(s):  
Wolfgang Jeitschko ◽  
Rainer O. Altmeyer
Keyword(s):  
Single Crystal ◽  
Crystal Chemistry ◽  
Homogeneity Range ◽  
Type Structure ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Lattice Constants ◽  
Rich Side

Crystals of Rh2Sb were prepared by sintering the elemental components in a NaCl/KCl flux. They crystallize in the orthorhombic space group Pnma with the lattice constants α = 572.1(1)-573.6(1) pm, b = 417.1(1)-418.1(1) pm, c = 792.8(2)-794.9(1) pm, V = 0.1892-0.1906 nm3 for the antimony- and rhodium-rich side, respectively, of the homogeneity range at 800 °C. The structure belongs to the Co2Si-branch of the (anti-)PbCl2-type. It was refined from single-crystal diffractometer data to a residual R = 0.059. The crystal chemistry of the various PbCl2-type compounds is briefly reviewed.

BaCu6Ge2S8 -Ein Thiogermanat als Variante der Li3Bi-Struktur / BaCu6Ge2S8 -A Thiogermanate as a Variant of the Li3Bi Structure

1998 ◽  
Vol 53 (12) ◽  
pp. 1483-1488 ◽  
Author(s):  
Markus Tampier ◽  
Dirk Johrendt
Keyword(s):  
Single Crystal ◽  
Spatial Orientation ◽  
Type A ◽  
Structure Type ◽  
Direct Reaction ◽  
Orthorhombic Structure ◽  
X Ray ◽  
Metal Atoms ◽  
Face Centered

Abstract BaCu6Ge2 S8 was synthesized by direct reaction of the elements at 750°C and characterized by X-ray single crystal techniques. The thiogermanate crystallizes in a new orthorhombic structure type (a = 6.122(1) Å, b = 12.084(3) Å, c = 17.614(5) Å; Pbcm, Z = 4). Isolated [GeS4]4- tetrahedra form a slightly distorted cubic face-centered (fee) arrangement. Baand Cu-atoms each occupy half the octahedral gaps (OG) of this “tetrahedra packing” . Further Cu atoms fill the tetrahedral gaps ( TG) completely. The compound can be written as Ba2(1/2OG)(Cu2)2(1/2OG)Cu8(TG)(GeS4)4 . Thus the structure of BaCu6Ge2S8 can be derived from the Li3Bi type. The sulfur coordination of the metal atoms (Cu tetrahedral or trigonal, Ba with CN 8) are realized by the spatial orientation of the [GeS4]4- tetrahedra. Their centers nearly maintain the fcc-arrangement. This structure interpretation of BaCu6 Ge2S8 from the viewpoint of a “filled tetrahedra packing” is discussed for further known thiogermanate compounds.

Ternary Antimonides LnTSb3 with Ln = La-Nd, Sm and T = V, Cr

1995 ◽  
Vol 50 (6) ◽  
pp. 899-904 ◽  
Author(s):  
Markus Brylak ◽  
Wolfgang Jeitschko
Keyword(s):  
Transition Metal ◽  
Single Crystal ◽  
Structure Type ◽  
Variable Parameters ◽  
X Ray ◽  
Metal Site ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Structure Factors ◽  
Infinite Strings

The title compounds were prepared by reaction of the elemental components. They crystallize in a new structure type, which was determined from single-crystal X -ray data of CeCrSb3: Pbcm, a = 1310.8(3), b = 618.4(1), c = 607.9(1) pm, Z = 4, R = 0.029 for 648 structure factors and 32 variable parameters. The structure of the antimonide CeVSb3 is isotypic: a = 1319.0(2), b = 623.92(8), c = 603.03(8) pm , R = 0.041 for 477 structure factors and 32 variables. The transition metal site and one of the three antimony sites were found to have partial occupancies resulting in the exact compositions CeV0,91(1)Sb2,916(4) and CeCr0,901(9)Sb2,909(4). The structures contain fractional Sb -Sb bonds with distances varying between 301,5 and 316.4 pm. The transition metal atoms have octahedral antimony coordination. These TSb6 octahedra share faces resulting in linear infinite strings with V - V and Cr - Cr bond distances of 301.5 and 304.0 pm, respectively. The structure of these com pounds contains building elements, which are also found in antimonides with ThCr2Si2, CaBe2Ge2, and HfCuSi2 type structures.

U3TiSb5, U3VSb5, U3CrSb5, and U3MnSb5 with "Anti"-Hf5Sn3Cu Type Structure

1994 ◽  
Vol 49 (6) ◽  
pp. 747-752 ◽  
Author(s):  
Markus Brylak ◽  
Wolfgang Jeitschko
Keyword(s):  
Transition Metal ◽  
Single Crystals ◽  
Type Structure ◽  
Interatomic Distances ◽  
X Ray ◽  
Lattice Constants ◽  
Arc Melting ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Structure Factors

The title compounds have been prepared from the elemental components by arc-melting and subsequent annealing. Single crystals of U3TiSb5 and U3MnSb5 were obtained from a tin flux and their structures were determined from single-crystal X-ray data: P63/mcm, Z = 2; a = 913.9(2), c = 611.2(1) pm, R = 0.011 (233 structure factors, 14 variables) for U3TiSb5 and a = 916.8(2), c = 613.2(1) pm, R = 0.015 (427 structure factors, 14 variables) for U3MnSb5. The lattice constants of the isotypic compounds are: a = 908.2(2), c = 608.3(2) pm for U3VSb5 and a = 911.0(1), c = 611.5(1) pm for U3CrSb5. The structure of these antimonides may be regarded as an “anti”-type structure of Hf5Sn3Cu with the antimony atoms on the hafnium sites, while the positions of the uranium and transition metal atoms correspond to the positions of the tin and copper atoms. A comparison of the interatomic distances of U3TiSb5 with those of U3Sb4, USb2, and a-antimony suggests oxidation numbers according to (U+III)3Ti+IV(Sb1-III)3(Sb2-II)2, where the Sb2 atoms form weakly bonded chains

The Lanthanoid Osmium Gallides Er2Os3Ga10 and Tm2Os3Ga10 with Yb2Ru3Ga10-type Structure

2009 ◽  
Vol 64 (5) ◽  
pp. 499-503 ◽  
Author(s):  
Wolfgang Jeitschko ◽  
Martin Schlüter
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Intermetallic Compounds ◽  
High Frequency ◽  
Type Structure ◽  
Variable Parameters ◽  
X Ray ◽  
Lattice Constants

The title compounds were prepared by melting and annealing of stoichiometric mixtures of the elemental components in a high-frequency furnace. They are isotypic with Yb2Ru3Ga10 (P4/mbm, Z = 2). Their lattice constants were determined from X-ray powder data, and their crystal structures were refined from single-crystal X-ray data. Er2Os3Ga10: a = 883.4(1), c = 636.7(1) pm, R = 0.025 for 506 Fo values, and Tm2Os3Ga10: a = 883.2(1), c = 633.6(1) pm, R = 0.023 for 568 Fo values and 25 variable parameters each. The crystal structures of these intermetallic compounds are briefly discussed.

scholarly journals Lu-atom-ordered oxonitridoaluminosilicate Ba0.9Ce0.1LuAl0.2Si3.8N6.9O0.1

2020 ◽  
Vol 76 (11) ◽  
pp. 1708-1711
Author(s):  
Rayko Simura ◽  
Hisanori Yamane
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Hexagonal Lattice ◽  
Crystal Structure Analysis ◽  
Mixed Powder ◽  
X Ray ◽  
Lattice Constants ◽  
Coordination Sites ◽  
Nitride Oxide ◽  
Single Crystal Structure Analysis

A single crystal of Ba0.9Ce0.1LuAl0.2Si3.8N6.9O0.1 (barium cerium lutetium aluminosilicate nitride oxide) was obtained by heating a mixed powder of Ba3N2, Si3N4, Al, Lu2O3, and CeO2 at 2173 K for 1 h under N2 gas at 0.85 MPa. X-ray single-crystal structure analysis revealed that the title oxynitride is hexagonal (lattice constants: a = 6.0378 (5) Å, c = 9.8133 (9) Å; space group: P63 mc) and isostructural with BaYbSi4N7. (Ba,Ce) and Lu atoms occupy twelvefold and sixfold coordination sites, respectively.

Structure and Thermoelectric Properties of New Quaternary Tin and Lead Bismuth Selenides, K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1+xSn5-xBi11+xSe22

2000 ◽  
Vol 626 ◽  
Author(s):  
Antje Mrotzek ◽  
Kyoung-Shin Choi ◽  
Duck-Young Chung ◽  
Melissa A. Lane ◽  
John R. Ireland ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Single Crystal ◽  
Thermoelectric Properties ◽  
Three Dimensional ◽  
Structure Type ◽  
Narrow Gap ◽  
Low Thermal Conductivity ◽  
Seebeck Coefficients ◽  
Metal Atoms ◽  
Anionic Framework

ABSTRACTWe present the structure and thermoelectric properties of the new quaternary selenides K1+xM4–2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22. The compounds K1+xM4-2xBi7+xSe15 (M= Sn, Pb) crystallize isostructural to A1+xPb4-2xSb7+xSe15 with A = K, Rb, while K1-xSn5-xBi11+xSe22 reveals a new structure type. In both structure types fragments of the Bi2Te3-type and the NaCl-type are connected to a three-dimensional anionic framework with K+ ions filled tunnels. The two structures vary by the size of the NaCl-type rods and are closely related to β-K2Bi8Se13 and K2.5Bi8.5Se14. The thermoelectric properties of K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22 were explored on single crystal and ingot samples. These compounds are narrow gap semiconductors and show n-type behavior with moderate Seebeck coefficients. They have very low thermal conductivity due to an extensive disorder of the metal atoms and possible “rattling” K+ ions.

Verfeinerung der Kristallstruktur von Tripalladium-di-tetrathiophospliat Pd3(PS4)2 Refinement of the Crystal Structure of Tripalladium-di-tetrathiophosphate Pda3(PS4)2

1983 ◽  
Vol 38 (4) ◽  
pp. 426-427 ◽  
Author(s):  
Arndt Simon ◽  
Karl Peters ◽  
Harry Hahn
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Title Compound ◽  
Type Structure ◽  
Tetrahedral Symmetry ◽  
X Ray ◽  
X Ray Crystallography ◽  
Planar Environment

Abstract The structure of the title compound has been determined by X-ray crystallography. The title compound is synthesized from the elements at 600 °C. Its crystal structure, derived from powder data [3] is refined by single crystal diffractometer data. The structure is trigonal (P3̅ml, α = 684.1(1), c = 724.4(1) pm); Pd2+ cations and PS43- anions form a network with an anti-Claudetite (AS2O3) type structure. The PS4 units are distinctly distorted from ideal tetrahedral symmetry. The Pd atoms have a planar environment of 4 S atoms.

Die Kristallstrukturen der isotypen Verbindungen Ba3[MoN4] und Ba3[WN4] / The Crystal Structures of the Isotypic Compounds Ba3[MoN4] and Ba3[WN4]

1991 ◽  
Vol 46 (5) ◽  
pp. 566-572 ◽  
Author(s):  
Axel Gudat ◽  
Peter Höhn ◽  
Rüdiger Kniep ◽  
Albrecht Rabenau
Keyword(s):  
Transition Metals ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structure Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ternary Compounds ◽  
The Third

The isotypic ternary compounds Ba3[MoN4] and Ba3[WN4] were prepared by reaction of the transition metals with barium (Ba3N2, resp.) under nitrogen. The crystal structures were determined by single crystal X-ray diffraction: Ba3[MoN4] (Ba3[WN4]): Pbca; Z = 8; a = 1083.9(3) pm (1091.8(3) pm), b = 1030.3(3) pm (1037.5(3) pm), c = 1202.9(3) pm (1209.2(4) pm). The structures contain isolated tetrahedral anions [MN4]6- (M = Mo, W) which are arranged in form of slightly distorted hexagonal layers and which are stacked along [010] with the sequence (···AB···). Two of the three Ba atoms are situated between, the third one is placed within the layers of [MN4]-groups. In this way the structures can be derived from the Na3As structure type.

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