The infrared absorption spectra of mixed Ag3[AsO4, VO4] crystals

Abstract

Mixed Ag3[AsO4, VO4] crystals were prepared over the whole concentration range. In the 0-40% mol. Vanadate concentration range the mixed crystals are isostructural with Ag3AsO4 (T4d, Z = 2). Site- and factor group analyses were carried out for this space group and structure. Above 60 mol% vanadate, the mixed crystals are tetragonal with Ag3VO4 structure. It follows from the behaviour of the ν4AsO3-4 vibration that, in cubic mixed crystals with 40 mol% Ag3VO4, the site-symmetry T is reduced to effective site-symmetry C3 by the effect of lattice vibrations of the T(F) and R(F) types.