Kinetics and mechanism of the oxidation of thiosulphate ion by tetrakis (2,2'-bipyridine)-µ-oxodiiron (III) ion in aqueous acidic medium

Abstract

The kinetics of the oxidation of thiosulphate ion by tetrakis(2,2'-bipyridine)-µ- oxodiiron(III) ion has been investigated in aqueous acidic medium at 30°C. Increase in concentration of acid increased the reaction rate. The reaction obeyed a general rate law:
1 d[Fe²⁺] = k_obs [Fe₂ O⁴⁺]
2      dt
where k_obs = a + b [H⁺]²
Added anions have no effect on the reaction rate. The outersphere mechanistic pathway is proposed for the reaction.

Keywords: Kinetics, reduction, mechanism, oxobridged binuclear complex ion, outer-sphere