SUPERCONDUCTIVITY OF A NEW PHASE WITH THE HEXAGONAL NB3S4 TYPE-STRUCTURE - PREPARATION, CRYSTAL-STRUCTURE AND ELECTRICAL-PROPERTIES OF NONSTOICHIOMETRTC INDIUM VANADIUM SULFIDE

The nonstoichiometric ternary compound In0.69V6S8 was prepared via a l ow temperature diffusion reaction between hexagonal V3S4 and In metal. The crystal structure solution reveals that In is strongly disordered within the hexagonal channels of the structure. The analysis of the s tructural data in connection with the data of other ternary A(x)V(6)S( 8) phases gives evidences that the V-V bond length within the metal at om zig-zag chains parallel to the crystallographic c-axis is nearly no t affected by the valence electron concentration (VEC) per V atom. On the other hand the distance between the chains increases with raising VEC, independent of the nature of the electropositive element A. The e lectrical resistivity of In0.69V6S8 was measured between 2 and 300 K. For the first time we have observed superconductivity in this compound . The title compound shows a transition into the superconducting state with a transition temperature T-C of 3.7 K.