Reactions of Dithionite and Thiosulfate

In a separate study of the reduction of several metal complexes of Fe(III), Co(III), and Mn(III) to the corresponding bivalent species, the two-component rate law is observed [equations (12) and (13)]. 

Radical intermediates have also been invoked in the mechanism of reduction of thiosulfate by Mn(VII). An outer-sphere activated complex is proposed in the one-electron transfer process leading to 8203 radical formation. Further rapid oxidation of the intermediate by MnO yields SOl. The reaction of S2O3 with [Mo(CN)8l is first order with respect to each reagent and independent of hydrogen ion concentration.Catalysis by metal ions is observed, however, indicative of a bridging role in the activated complex. 

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