High-pressure synthesis of a new copper thioborate, CuBS2

A new copper thioborate, CuBS2, was synthesized at high-pressure/temperature condition of 3 GPa and 700-900 degrees 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-42d), isostructural with CuMS2 chalcopyrite compounds (M: Al, Ga, and In). The compound is the first representative of the chalcopyrite-type family consisting of BS4-tetrahedra. From the UV-Vis diffuse reflectance spectrum, the optical band gap of CuBS2, was estimated to be E-g=3.61 eV. (c) 2006 Elsevier B.V. All rights reserved.