Complements apportes au diagramme tension-pH du manganese

Abstract

The theoretical tension-pH diagram of manganese, which has been established previously, must be reconsidered on the basis of studies, made in our laboratory, on the electrochemical behaviour of different manganese-dioxide ores. The study of non-stoichiometric oxides leads to a general formula for these compounds MnO x (OH) 4-2 x . Starting from this symbol, we have rewritten all the chemical and electrochemical reactions which may be possible. We also have shown that it is possible to consider reactions with manganite. This phase is not mentioned in the preceding diagram. This new theoretical diagram is based on experimental results that have been extrapolated, but nevertheless enables some equilibria to be considered in a more generalized way, especially those where the different non-stoichiometric varieties may interfere. The only variety considered in the preceding work was β-MnO 2.