Two series of single crystals of CuCrS were prepared: series I single crystals were quenched from 850°C to room temperature, series II were slowly cooled (50°C/day). In the series II-CuCrS 2 , Cu atoms are ordered and occupy half of the tetrahedral sites. Series I-CuCrS 2 is non-stoichiometric and 10% of the Cu atoms are in the interstatial position. Transport properties indicate a semi-conducting comportement of both phases. Magnetic susceptibility measurements confirm an antiferromagnetic ordering (T N = 40K). The resolved structures and observed properties are compared to the related Ti and V derivates (CuTiS 2 , Cu 0.75 VS 2 and Cu 0.65 VS 2 ) which are metallic.

Single crystals of CuV2S4 have been made by chemical vapor transport with chlorine as the transport agent. Characterization by an X-ray study, density measurements by the hydrostatic technique and electron microprobe analysis were performed. They showed no deviation from stoichiometry of the compound. Refinement of the structure (space group Fd3m) has been done. Transport properties, magnetic susceptibility and N.M.R. data from 1.5°K to 300°K present discontinuities below 100°K. Observed properties are discussed in view of the previously proposed band model. The relationships between magnetic susceptibility and Knight shifts are included in this paper.

A second form of compounds CuxVS2 is described here. As in Cu0.75VS2 (1) the structure of Cu0.65VS2 is related to the CdI2-type. In Cu0.75VS2, Cu atoms are ordered in tetrahedral sites between the CdI2-type subunits, whereas in the Cu0.65VS2, Cu atoms are partially disordered and occupy 4 different sites. Both structures differ from one another in vanadium atoms arrangements: In Cu0.75VS2, V-atoms form triangular clusters while in Cu0.65VS2 they form zigzag chains perpendicular to the hexagonal axis. The physical properties show a metallic type behaviour. Resistivity decreases with temperature with low 300 K/4.2 K ratio according to a disordered nature of the compound. Magnetic susceptibility shows a Pauli paramagnetism with an additionnal Curie-Weiss term due to a relatively large amount of paramagnetic impureties (0,9 % V3+ atoms). The observed low temperature localisation of the 3d electrons in Cu0.75VS2 disappears in the case of Cu0.65VS2.

La2Fe1.76S5 is the second member of the family of superstructures derived from La2Fe2S5 by introducing iron vacancies in the double chain of tetrahedrally and octahedrally coordinated iron atoms. The cell is orthorhombic (space group Pmc21) with parameters a = 4.001 Å; b = 32.936 Å = 2 b′ (b′ parameter of La2Fe2S5); c = 11.291 Å; Z = 8. The crystal structure has been refined to R = 0.057. Vacancies which are located on three iron sites are ordered in the bc plane but disordered along the a axis. They lead to important distortions in the chains only when they appear on an octahedrally coordinated iron atom. In this case the coordinating figure of the associated tetrahedral iron atom is changed, and the chain becomes a canal of closely spaced iron atoms.

The compound La2Fe2S5 is orthorhombic. Cell parameters are: a = 3.997(2)Å; b = 16.485(5)Å; c = 11.394(4)Å. Space group is Cmc21 (Z = 4. In the cell, chains of polyedra comprised of sulfur atoms tetrahedrally or octahedrally coordinating centrally located iron atoms give a monodimensional character to the structure. This one is refined to R = 0.037. To complete the study of these chains, in the La2Fe2−xS5 system, vacancies are introduced on iron atom sites. The ordered compound, La2Fe1.87S5, having such vacancies, is an orthorhombic superstructure of the stoechiometric compound. Cell parameters are: a = 3.9996(5)Å; b = 49.508(3)Å; c = 11.308(3)Å. Space group is Cmc21 and Z = 12. The structure is refined to R = 0.068. Only two iron atom sites have vacancies. One is tetrahedral, the other octahedral. In this last case the chain deformations are the more important. The chain becomes a sort of tunnel made of atoms of sulfur, with in its center the short iron-iron separation of 2.82 Å.

The preparation, crystal structure, and electrical and magnetic properties of the compound CuxTiS2 (0,7 < x < 1) are reported. This compound is a member of the family of layer compounds ABX2 (A = Cu, Ag; B = Cr, V, Ti; X = S, Se, Te) with atoms X forming a cubic closed-packed array, atoms B occupying the octahedral holes between alternate X sheets and atoms A located in the tetrahedral holes in the remaining vacant layers. A three-dimensional X-Ray structure determination was performed on a single crystal of composition Cu0.70TiS2 with the final discrepancy indices R = 0.037, wR = 0.043. The structure is related to CdI2 with the unit cell derived from 3 CdI2 cells that are translated by |13, 13, 1| and with Cu atoms disordered in two independent tetrahedral sites between the CdI2-type subunits. The magnetic susceptibility exhibits Pauli-paramagnetic behaviour and the results of Hall measurements confirm the metallic nature of the compound.

Preparations of powdered and crystalline αGa2S3 are described. Structure of αGa2S3 is established from single crystal determination (R = 0.058). These is a superstructure of wurtzite type, with ordered vacancies on gallium positions. A polymorphism of Ga2S3 is described.

The preparation, crystal structure and physical properties of normal spinel Cu1−xTi2S4 are reported. A large range of compositions (0⩽x⩽0.44) has been observed. Single crystals have been obtained by chemical vapor transport reaction with iodine or chlorine pressure. The refinement of the structure (67 reflexions) corroborates the previous normal spinel structure and indicates for this crystal a composition of Cu0.93Ti2S4. Electrical and magnetic properties have been measured for some single crystals. They are consistent with the metallic conductivity as shown by the proposed band structure model.

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 I4mmm, 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.

AbstractAus den Sulfiden der einzelnen Metalle wurden die Verbindungs gruppen (I) bis (IV) erhalten.