High-pressure synthesis of a new copper thioborate, CuBS 2

Abstract

A new copper thioborate, CuBS 2, was synthesized at high-pressure/temperature condition of 3 GPa and 700–900 °C. The crystal structure was refined by the Rietveld analysis of the powder X-ray diffraction data. The compound crystallizes into a tetragonal unit cell ( a = 0.5044(1) nm, c = 0.8947(2) nm, space group: I-42 d), isostructural with CuMS 2 chalcopyrite compounds (M: Al, Ga, and In). The compound is the first representative of the chalcopyrite-type family consisting of BS 4-tetrahedra. From the UV–Vis diffuse reflectance spectrum, the optical band gap of CuBS 2 was estimated to be E g = 3.61 eV.