SYNTHESIS OF CALCIUM METANIOBATE BY THERMAL-DECOMPOSITION OF A COPRECIPITATION PRODUCT

The paper presents a new, nonconventional method, based upon coprecipi tation, for the synthesis of niobium oxidic compounds. The coprecipita tion product of niobic acid with calcium oxalate was used as precursor . Calcium metaniobate was obtained by appropriate thermal treatment of the coprecipitate. The coprecipitation mechanism was studied and the optimal conditions for quantitative precipitation of niobium and calci um were established. The mechanism of thermal decomposition of the cop recipitate was investigated by means of differential thermal analysis and X-ray powder diagrams. The final product of thermal decomposition, calcium metaniobate, is formed at 730-degrees-C.