The synthesis of metavivianite and the oxidation sequence of vivianite

Abstract

A mixture of metavivianite, vivianite, and spheniscidite was obtained from an aqueous solution of FeSO₄·7H₂O and (NH₄)₂HPO₄ at temperatures between 50 and 60 °C. The oxidation sequence of partially oxidized vivianite toward santabarbaraite or a solid solution between β–Fe₂(PO₄)O and Fe₄(PO₄)₃(OH)₃, without passing through metavivianite, was also demonstrated.