STRUCTURAL EVOLUTIONS IN THE PHOSPHATE AND VANADATE AMXO₄ SERIES (A=Li⁺, Na⁺, Cu⁺, Ag⁺, M=Cd²⁺, Mn²⁺, X=V⁵⁺, P⁵⁺)

Abstract

In the AMXO₄ series (A=Li⁺, Na⁺, Cu⁺, Ag⁺, M=Cd²⁺,Mn²⁺, X=V⁵⁺,P⁵⁺) all the compounds, except AgMnPO₄, crystallize with olivine, Na₂CrO₄ or maricite-type structure. When the size of the counter-cation A⁺ increases structural changes from olivine or Na₂CrO₄-type to maricite-type structure are observed. The destabilization of these two structures is also correlated to the size of the M²⁺ cations.