A new Sb-based polysulfide: Ba3Sb2S7 containing (S2)2− ligand

A new ternary sulfide Ba3Sb2S7 was synthesized from high temperature solid-state reactions in a flame-sealed silica ampoule. It crystallizes in the C2/c space group of the monoclinic system with a = 18.380(2) Å, b = 12.266(2) Å, c = 13.164(2) Å, β = 110.054(6)°, V = 2788.0(7) Å3, and Z = 8. The compound features an interesting zero-dimensional structure built of two types of isolated SbS3 and SbS2(S2) units surrounded with the charge balanced Ba2+ cations. The UV–Vis–NIR optical diffuse reflectance measurements along with the electronic band structure calculations indicate that Ba3Sb2S7 belongs to an indirect semiconductor with the band gap of 2.4 eV. Electronic density of states (DOS) analyses were also performed to interpret the intrinsic behavior of charge transfers in the SbS3 and SbS2(S2) units, respectively.