Water soluble Na[Nb(O2)3]•2H2O as a new molecular precursor for synthesis of sodium niobate

A water-soluble tetraperoxo niobate [Nb(O-2)(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(O-2)(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(O-2)(4)], and Na2CO3. Based on the elemental, TG, redox titration and Raman spectroscopic analyses, we have concluded that the obtained compound was Na[Nb(O-2)(3)]center dot 2H(2)O. 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 degrees C.