New compounds in the cesium sulfobromide rhenium octahedral cluster chemistry: syntheses and crystal structures of Cs_4Re_6S_8Br_6 and Cs_2Re_6S_8Br_4

摘要

The exploration of the Cs-Re-S-Br system, in order to identify new phases based on octahedral cluster anions, has produced single crystals of Cs_4Re_6S_8Br_6 (1) (trigonal, space group P-6c2, a = 9.7825 (3) A, c = 18.7843 (5) A, V = 1556.77 (1) A~3, Z = 2, density = 5.09 g cm~(-3), β = 36.07 mm~(-1)) and Cs_2Re_6S_8Br_4 (2) (monoclinic, space group P2_1, a = 6.3664 (1) A, b = 18.4483 (4) A, c = 9.3094 (2) A, β = 104.2618 (8)°, V = 1059.69 (4) β~3, Z = 2, density = 6.14 g cm~(-3_, μ = 45.83 mm~(-1)). These two compounds have been obtained by high-temperature solid state route. Their structures have been solved and refined from single crystal X-ray diffraction data. The structure of Cs4Re6S8Br6 presents isolated anionic cluster units inscribed in a (Cs~+)_(12) cuboctahedron and the one of Cs_2Re_6S_8Br_4 exhibits R~(i-a,a-i)-Re inter-unit bridges. The framework of the latter presents then a strongly 1-D character.