Cd5P2Br4: First cadmium analogue of the Million's base salts

A. new cadmium pnictide halide-Cd5P2Br4-was synthesized, and its structure was determined (R = 0.0525). The compound crystallizes in the orthorhombic symmetry system, space group Pna2(1) (a = 12.189 Angstrom, b = 7.7080 Angst rom, c = 13.664 Angstrom, Z = 4). A characteristic feature of the Cd5P2Br4 structure is a distorted tridymite-type framework composed of cadmium and p hosphorus atoms. The framework cavities accommodate discrete tetrahedral gr oups CdBr4. Such a structure makes it possible to classify the new compound as the first cadmium-phosphorus analogue of Millon's base salts. The struc ture of Cd5P2Br4 is compared to the structure of Hg5P2Br4, another phosphor us-containing analogue of Millon's base salts.