Oxalate complexes of Pa(V)

The solubility of Pa(V) hydroxide in solutions of oxalic acid was investigated. The dependence of the solubility of protactinium hydroxide on the oxalic acid concentration was related to the properties of the oxalate complexes of protactinium formed. Thus, for example, the low solubility of the hydroxide in 0.01–0.05 M solutions of oxalic acid is evidently explained by the formation of a hydroxyoxalate complex of protactinium with a 11 composition.The composition of the readily soluble protactinium oxalate, isolated from solution by salting out with acetone, was studied. The Pa:C₂O ₄ ^–2 ratio in the complex was equal to 12. It was shown that the precipitates obtained as a result of hydrolytic deposition of protactinium according to the Kirby method from solutions of hydrochloric and oxalic acids contain oxalate and chloride ions.Translated from Atomnaya Énergiya, Vol. 22, No. 5, pp. 389–392, May, 1967.