Water Soluble Na[Nb(O<sub>2</sub>)<sub>3</sub>]•2H<sub>2</sub>O as a New Molecular Precursor for Synthesis of Sodium Niobate

Abstract

A water-soluble tetraperoxo niobate [Nb(O2)4]3- was prepared by reaction of niobic acid with H2O2 at pH=11 in aqueous ammonia solution. The corresponding ammonium salt, (NH4)3[Nb(O2)4], was grown as a single crystal, and its crystal structure was solved. A white precipitate has been obtained from the solution containing (NH4)3[Nb(O2)4] and Na2CO3. Based on the elemental, TG, redox titration and Raman spectroscopic analyses, we have concluded that the obtained compound was Na[Nb(O2)3]•2H2O. This compound has been demonstrated to be a convenient precursor for synthesis of NaNbO3 by simple calcinations in air at the reduced temperature of 400-500°C.