Mild Solvothermal Syntheses and Characterization of Layered Copper Thioantimonates(III) and Thioarsenate(III)

The new copper thioantimonates­(III) and thioarsenate­(III) Rb2Cu2Sb2S5 (1), Cs2Cu2Sb2S5 (2), and Rb8Cu6As8S19 (3) have been synthesized solvothermally. Compound 1 contains a [Cu2SbS3] net to which [Sb2S4] chains adhere through Cu–S bonds and Sb–Cu interactions to give a layered structure. In compound 2, the layer is formed by edge-sharing tetrahedral CuS4 chains linked by dimeric [Sb2S5] units. The layered structure in compound 3 is constructed by helical chains built from [Cu3S7] moieties and dimeric [As2S5] units which are further connected by tetrameric [As4S9] groups. Their optical and thermal properties have been investigated.