Etude structurale de combinaisons sulfurées et séleniées du molybdène. III. Structure cristalline de NiMo 3S 4

The crystals of NiMo ₃S ₄, are rhombohedral, space group R overline3, with two formula units in a cell: a = 6.462 Å, α = 94.68°. The structure was solved by the heavy atom method and refined by a full-matrix least-squares program to R = 0.077 for 1026 independent reflexions. The arrangement of Mo and S atoms in the cell is approximately the same as described before for Mo and Se atoms in Mo ₃Se ₄ and Ni _0.33Mo ₃Se ₄; the Ni atoms are situated along the channel based on x = 0, y = 0. However, in these two compounds the lattice of Se presents a covalent character when the lattice of S in NiMo ₃S ₄ has an essentially ionic character.