Refinement of the crystal structures of Cu3PS4 and Cu3SbS4 and a comment on normal tetrahedral structures

Abstract

Abstract The crystal structures of yellow Cu3PS4 and of black Cu3SbS4 were refined from single crystal X-ray diffraction data. Cu3PS4 crystallizes orthorhombic in an ordered wurtzite superstructure type with the space group Pmn21 (no. 31), a = 7.282(1) Å, b = 6.339(1) Å, c = 6.075(1) Å, V = 280.38(8) Å3, and Z = 2. The refinement converged to R = 0.0276, and wR2 = 0.0710 for 737 unique reflections and 44 parameters. Cu3SbS4 crystallizes tetragonal in an ordered sphalerite superstructure type with the space group I4̅2m (no. 121), a = 5.391(1) Å, c = 10.764(1) Å, V = 312.83(9) Å3, and Z = 2. The refinement converged to R = 0.0213, and wR2 = 0.0532 for 492 unique reflections and 14 parameters. The crystal structures of the title compounds and related normal tetrahedral structures are discussed with respect to the preference of either hexagonal or cubic packing of the anions.