I-V-VI2 compounds (I = Ag, V = Sb, Bi, VI = S, Se, Te) crystal structure, lattice parameters, phase transitions

The crystal structure of the room-temperature modification of K[Hg(SCN)3], potassium trithiocyanatomercurate(II), was redetermined based on modern CCD data. In comparison with the previous report [Zhdanov & Sanadze (1952).Zh. Fiz. Khim.26, 469–478], reliability factors, standard deviations of lattice parameters and atomic coordinates, as well as anisotropic displacement parameters, were revealed for all atoms. The higher precision and accuracy of the model is, for example, reflected by the Hg—S bond lengths of 2.3954 (11), 2.4481 (8) and 2.7653 (6) Å in comparison with values of 2.24, 2.43 and 2.77 Å. All atoms in the crystal structure are located on mirror planes. The Hg2+cation is surrounded by four S atoms in a seesaw shape [S—Hg—S angles range from 94.65 (2) to 154.06 (3)°]. The HgS4polyhedra share a common S atom, building up chains extending parallel to [010]. All S atoms of the resulting1∞[HgS2/1S2/2] chains are also part of SCN−anions that link these chains with the K+cations into a three-dimensional network. The K—N bond lengths of the distorted KN7polyhedra lie between 2.926 (2) and 3.051 (3) Å.

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New Quaternary Chalcogenides Tl2MIIMIV3Se8 and Tl2MIIMIVX4

Proceedings ◽

10.3390/proceedings2020062003 ◽

2020 ◽

Vol 62 (1) ◽

pp. 3

Author(s):

Andrii Selezen ◽

Yuri Kogut ◽

Lyudmyla Piskach ◽

Lubomir Gulay

Keyword(s):

Crystal Structure ◽

Ternary Systems ◽

Lattice Parameters ◽

Tetragonal Symmetry ◽

Orthorhombic Symmetry ◽

Component Ratio

New quaternary thallium-containing chalcogenides Tl2MIIMIV3X8 and Tl2MIIMIVX4 were synthesized, and their crystal structure was determined by XRD. Three Tl2MIIMIV3X8 chalcogenides crystallize in orthorhombic symmetry (S.G. P212121; Tl2CdGe3Se8 lattice parameters a = 0.76023(9), b = 1.2071(2), c = 1.7474(2) nm), eight isostructural Tl2BIIDIVX4 compounds crystallize in tetragonal symmetry, S.G. I-42m. These compounds form in the quasi-ternary systems Tl2X–MIIX–MIVX2 (X–S, Se, Te) at the component ratio 1:1:1 and 1:1:3 at the sections Tl2MIVX3–BIIX and Tl2MIIMIVX4–MIVX2, respectively. The composition of the Tl2CdGe3Se8 compound was additionally confirmed by SEM and EDS.

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Single-crystal investigation of Ce5AgxGe4−x (x = 0.1−1.08) with Sm5Ge4 type

Zeitschrift für Naturforschung B ◽

10.1515/znb-2020-0091 ◽

2020 ◽

Vol 75 (8) ◽

pp. 765-768

Author(s):

Bohdana Belan ◽

Dorota Kowalska ◽

Mariya Dzevenko ◽

Mykola Manyako ◽

Roman Gladyshevskii

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Diffraction Data ◽

Binary Compound ◽

Lattice Parameters ◽

X Ray Diffraction ◽

Space Group ◽

X Ray

AbstractThe crystal structure of the phase Ce5AgxGe4−x (x = 0.1−1.08) has been determined using single-crystal X-ray diffraction data for Ce5Ag0.1Ge3.9. This phase is isotypic with Sm5Ge4: space group Pnma (No. 62), Pearson code oP36, Z = 4, a = 7.9632(2), b = 15.2693(5), c = 8.0803(2) Å; R1 = 0.0261, wR2 = 0.0460, 1428 F2 values and 48 variables. The two crystallographic positions 8d and 4c show Ge/Ag mixing, leading to a slight increase in the lattice parameters as compared to those of the pure binary compound Ce5Ge4.

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