Valence state of atoms in the perovskite-like phase SrxCu3V 4O12 (x = 0.67−1.0) and its properties

Abstract

We report the first synthesis, at high pressure and temperature (p = 6.0−8.0 GPa, t = 1000°C), of SrxCu3V4O12 (x = 0.67−1.0), a cation-deficient perovskite-like phase of variable composition (sp. gr. Im\(\bar 3\), Z = 2). Using x-ray photoelectron spectroscopy, we have determined the binding energies and valence states of atoms in SrxCu3V4O12. The stoichiometric composition of this phase can be represented by the chemical formula Sr2+Cu2+Cu2+ (V25+ V24+)O12. Air exposure leads to the formation of SrCO3 and Sr(OH)2 on its surface and to the oxidation of univalent copper and tetravalent vanadium. According to IR spectroscopy data, the penta-and tetravalent vanadium in the high-pressure phase is in octahedral oxygen coordination. The electrical conductivity, magnetic susceptibility, thermal properties, and ion selectivity of this compound have been investigated.