(CuI) 2 Cu 3 SbS 3 : Copper Iodide as Solid Solvent for Thiometalate ions

(CuI) 2 Cu 3 SbS 3 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) 2 Cu 3 SbS 3 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) Å 3 (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) 2 Cu 3 SbS 3 are dominated by strong bands for [SbS 3 ] 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 ‐5 ω ‐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).