The crystal structures of the room‐ and low‐temperature modifications of tris(η‐cyclopentadienyl)‐di‐μ3‐thio‐tricobalt, [Co3(η‐C5H5)3S2]

The crystal structures of the title compound at room temperature and at 130 K are determined. The roomtemperature modification is hexagonal, P63/m, with a = 9.413(2), c = 10.094(4) A and Z = 2, and is isostructural with [Nia(rl-CsH5)3S2 ] [(Vahrenkamp, Vernon, Uchtman & Dahl (1968). J. Am. Chem. Soc. 90, 3272-3273], except for the mode of statistical distribution of the r/-cyclopentadienyl rings. The Co-Co distance is 2.691 A which is definitely longer than those of most of the other trinuclear cobalt complexes, and this difference is explained by the Cotton-Haas theory of metal-metal bonding. The low-temperature modification is also hexagonal with a = 16.080 (2), c = 29.886 (2) A and Z = 18; this is a superstructure of the room-temperature modification and the symmetry can be given by the Mischgruppe P61 Up3 °. The trigonal bipyramid comprising Co3S 2 is no longer regular and the three r/-cyclopentadienyl rings take three definite orientations.