THE SINGLE-CRYSTAL STRUCTURE OF V5S8 DETERMINED AT 2 DIFFERENT TEMPERATURES - ANISOTROPIC CHANGES OF THE METAL ATOM NETWORK

The crystal structure of V5S8 was determined at 295 and 100 K. The the rmal expansion of the lattice parameters exhibits a pronounced anisotr opy. The contraction of the a-axis is significantly larger than that o f the other two axes. The average [V-S] bond lengths as well as the in teratomic separation between the V atoms parallel to the c axis show n o significant changes with temperature. In contrast, a remarkable decr ease of the distances between the V atoms in the metal cluster within the a-b plane is observed, indicative for stronger bonding interaction s. These increased bonding interactions are responsible for the unexpe cted anisotropic contraction of the lattice parameters with falling te mperature.