Solvent Extraction Studies of the Hydrolysis of Antimony(III) in Tracer Concentrations

Abstract

The hydrolysis of antimony(III) ions was investigated through solvent extraction with dithizone–carbon tetrachloride solutions. In a 3 M (H, Na)ClO4 solution, a tracer concentration of antimony(III) (<10−8M) was found in the form of a monovalent cation, Sb(OH)2+ or SbO+, and a neutral species, Sb(OH)3 or SbO(OH). The former is predominant in strongly acidic media, while the latter becomes abundant in the weakly acidicto-neutral region. One of the constants of successive hydrolysis, K1=[Sb(OH)2+][Sb(OH)3]−1[H+]]−1, was calculated from the distribution ratios, giving the result: logK1=1.236±0.06. The chemical composition of the extracted species was estimated to be Sb(HDz)3.