Crystal structure of Cd2V2O7

Cadmium pyrovanadate crystallizes in the C2/m space group with lattice parameters a = 7.088(5) Å, b = 9.091(5) Å, c = 4.963(5) Å, β = 103°21(5)′, and z = 2. This crystal is an isostructure of the mineral thortveitite and thus the anion consists of a pair of centrosymmetrically related corner-sharing VO 4 tetrahedra while the cation resides within a distorted octahedron of oxygen atoms. The anion has a linear VOV group, but, as with the isostructural pyrophosphates, the central oxygen atom shows an anomalously high thermal activity. The VO bond distances are 1.76 Å for the inner bond and 1.70 Å for the terminal bond. The bond angles about the anion and cation are similar to those found for the other analogues of thortveitite.