Kinetics and Mechanism of the Discharge-Ionization of Manganese in an Ammonium Chloride Solution

Analysis of the cathodic and anodic polarization curves recorded on manganese in a 2.0 M MnCl2 + 2.0 M NH4Cl solution (pH 5.5 ± 0.1 and t = 18 to 60°C) reveals the multistage character of the discharge-ionization of manganese in such a solution involving the formation of intermediate Mnads+ particles. The subsequent transformation of Mnads+ particles proceeds via either the electrochemical redox reaction or disproportionation. The inflection points in the cathodic polarization curves originate seemingly from the change in the surface charge of the electrode on passing the zero potential.