REDUCTION BEHAVIOR OF CARRIER-FREE SB-125 IN HYDROCHLORIC-ACID SOLUTIONS

The reduction reaction mechanism of carrier-free Sb-125 in HCl solutio n was studied kinetically. Sb(III) and Sb(v) were separated by solvent extraction using n-benzoyl-n-phenylhydroxylamine(BPHA) in chloroform at different constant time in interval and the reaction rate was deter mined by measuring the radioactivities of Sb-125 in both organic and a queous phases. Plot of log[Sb-125(V)/[Sb-125(III)+Sb-125(V)] against t he elasped time do not give straight lines. The curves can be solved t o be A --> B --> C type reactions by a non-linear squares. On the basi s of dependence of the reactions, overall reactions can be expressed a s follows; Sb(OH)CL(5)(-) (H+)(-->) SbCl6- (Cl-)(-->) Sb(III).