Preparation of tantalum phosphate, its structure and some properties

Abstract

The composition and some properties were studied for tantalum phosphate precipitate forming on heating a solution containing tantalum in the fluoro complex, hydrofluoric acid, sodium phosphate, and nitric or hydrochloric acid. Annealing of the precipitate leads to the defined compound TaOPO4. The tantalum-to-phosphate group ratio is 1 : 1 also in the precipitate freely dried at room temperature; in this form, tantalum undergoes hydrolysis in alkaline or weakly acidic solutions, whereas in strongly acidic solutions the hydrolysis is substantially suppressed. Annealed precipitate is stable in usual conditions. The dried precipitate exhibits sorption properties, whereas the annealed precipitate does not.