Reactions of liquid sodium with transition-metal oxides. Part VII. The oxides of niobium and tantalum

Abstract

The reactions of the oxides Nb₂O₅, NbO₂, NbO, and Ta₂O₅ with liquid sodium have been studied at 400 and 600 °C and the products examined by X-ray powder crystallography. In each case in which reaction took place the equilibrium products were found to be the transition metal together with the cubic form of Na₃NbO₄ or Na₃TaO₄. The possible reaction mechanisms of the oxides in liquid sodium are discussed. The reactions of the ternary oxides NaNbO₃, NaTaO₃, Na₃NbO₄, and Na₃TaO₄ with pure liquid sodium, and NaTaO₃ and Na₃TaO₄ with oxygen-doped liquid sodium, have all been studied.