Synthesis and crystal structure of the pyrovanadate Na2ZnV2O7

The compound Na2ZnV2O7 with an akermanite-type structure has been synthesized. It has a tetragonal unit cell, a = 8.2711(4), c = 5.1132(2) angstrom, and crystallizes with P-42(1)m symmetry, Z=2. Its crystal structure has been refined from a combination of X-ray and neutron powder diffraction data. The structure contains layers of corner-sharing VO4 and ZnO4 tetrahedra, the former in pairs forming pyrovanadate V2O7 units. The sodium atoms are positioned between the layers, with a distorted antiprismatic coordination of oxygen atoms. (c) 2005 International Centre for Diffraction Data.