(CuI)2Cu3SbS3: Copper Iodide as Solid Solvent for Thiometalate ions

Abstract (CuI)2Cu3SbS3 was prepared by solid‐state reaction of stoichiometric amounts of CuI, Cu, S, and Sb. The crystal structure was determined from single crystals at room temperature and ‐ 80°C. Red‐orange (CuI)2Cu3SbS3 crystallizes in the orthorhombic system, space group Pnnm (no. 58) with a = 10.488(2), b = 12.619(2), c = 7.316(1) Å, V = 968.2(2) Å3 (20°C), and Z = 4. The distribution of the copper atoms was refined by using a Gram‐Charlier nonharmonic development of their atomic displacement parameters, which indicated an increasing dynamic disorder from ‐80°C to 20°C. Raman spectra of (CuI)2Cu3SbS3 are dominated by strong bands for [SbS3]3‐ units at 362 and 338 cm‐1. The compound melts at 492°C (DTA, onset). Conductivity measurements reveal high ionic conductivity (6.2 × 10‐5ω‐1 cm‐1 at 50°C, 2.9 × 10‐3 ω‐1 cm‐1 at 200°C) with an activation energy of 0.35 eV (40–275°C).