Facile synthesis of cesium trithiocyanurate with high ionic conductivity and large birefringence properties

The crystal structure of a new cesium trithiocyanurate compound, Cs4(HC3N3S3)2·4H2O, was determined by X-ray diffraction analysis. Cs4(HC3N3S3)2·4H2O crystallizes in the space group Pnma, with cell parameters a = 21.961(5) Å, b = 11.928(3) Å, and c = 8.903(2) Å. Its structure consists of crosswise arranged (HC3N3S3)2− units, and Cs+ cations and H2O molecules are located in the voids. The title compound was characterized by IR and UV–vis diffuse reflectance spectroscopy and thermal analysis. In addition, electrochemical impedance spectrum measurements were performed and revealed that the title compound exhibits proton conduction with the conductivity on the order of 10−4 S cm−1. The electronic structure and calculated optical anisotropy of Cs4(HC3N3S3)2·4H2O were also reported, which demonstrated that the compound exhibits a very large birefringence (Δn = 0.236@800 nm).