Synthesis, structure and characterization of two new copper(І)-thioarsenates (ІІІ) constructed by the [AsS3]3− and CuSx units

Two new copper(І)-thioarsenates(ІІІ), CsCu2AsS3(1) and KCu4AsS4(2), have been synthesized solvothermally in the presence of copper powder. Compound 1 is built up of trigonal AsS3 pyramid, tetrahedral CuAsS3 and CuS3 moieties forming 4-membered, 5-membered and 6-membered rings. The fusion of these rings produces layered anions [Cu2AsS3]−, and cesium cations are located between metal-sulfide layers. The structure of 2 consists of infinite [Cu2S2]2− chain and layered [Cu6As2S6] linked to form a three-dimensional anionic framework, [Cu4AsS4]–, and containing channels in which the potassium cations reside.

Graphical abstractQne layered CsCu2AsS3 and one framework KCu4AsS4 possessing noncondensed [AsS3]3− unit have been synthesized solvothermally. The optical band gaps of the two compounds are 2.3 and 1.8 eV, respectively. Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We obtained two new copper(І)-thioarsenate(ІІІ), CsCu2AsS3 and KCu4AsS4. ► Both compounds possess noncondensed [AsS3]3− unit and represent new structure types. ► The optical band gaps of the two compounds are 2.3 eV and 1.8 eV, respectively.