Chloride-catalysed oxidation of thallium(I) by manganese(III) in aqueous perchlorate
Abstract
Manganese(III), in contrast with cobalt(III), does not react with thallium(I), except when manganese dioxide, from decomposition, or added chloride, are present. The observed rates in the presence of chloride are consistent with ‘reversible’ reaction of MnCl2+ with Cl– to give Cl2–, which oxidises Tl1 slowly and TlII rapidly. All TlIII appears as TlCl4–. Curvature of rate plots at > 70–80% reaction may be due to the presence of unreactive polynuclear MnIII, in perhaps <10% amounts. With an assumed association constant for MnCl2++ 13·5 l mol–1, the rate constant for MnCl2++ Cl– is 1·16 l mol–1 s–1.