Crystal structure, electronic structure and thermoelectric properties of Cu4Sn7S16

Single crystals of Cu4Sn7S16 have been prepared by direct reaction of the elements at 850 °C. The crystal structure was re-determined using single-crystal X-ray diffraction data. Cu4Sn7S16 crystallizes in the rhombohedral space group R3¯m (No. 166) with cell dimensions of a = 7.3788(2) Å, c = 36.032(2) Å, V = 1699(1) Å3 (Z = 3). The three-dimensional structure of this compound contains (in part severely distorted) CuS6 and SnS6 octahedra, CuS4 tetrahedra, and CuS4 trigonal pyramids. Electrical conductivity and Seebeck coefficient measurements show (n-type) semiconducting behavior, in agreement with the electronic band structure calculations.