Voltammetry study of Cr(III)/Cr(II) system in aqueous methanesulfonate solutions

► Violet and green forms of Cr(III) methanesulfonate ions. ► The electroreduction of Cr(III)-MSA complexes is irreversible on Pb, Cd and Sn electrodes. ► The electroreduction proceeds via an outer-sphere mechanism. ► Correlation between electrochemical and spectral characteristics of Cr(III) complexes.