A three-dimensional network structure built from selenodiphosphate(IV) and copper selenide tetrahedral building blocks: K3Cu3P3Se9

The reaction of red phosphorus, potassium polyselenide, and copper metal at moderate temperatures yields K₃Cu₃P₃Se₉. The structure was determined by single crystal X-ray diffraction (P2₁/c, a = 8.741(2) Å, b = 10.774(2) Å, c = 20.033(3) Å, β = 92.96(2)°). The structure consists of P₂Se₆]^4?-anions that link CuSe₄] tetrahedra in an open, three-dimensional, framework structure. A Valence Electron Concentration treatment of this structure reveals six different primary tetrahedral building blocks.