Manganese Chemical Properties

Manganese is located in the fourth period of the periodic table, group VIIB. It is a relatively active metal. It can combine with oxygen when heated, and is easily soluble in dilute acid to form divalent manganese salts.

1. Compound valence

The valence of manganese is +2, +3, +4, +5, +6, +7, -1, -2, -3. Among them, +2 (compound of Mn2+), +4 (manganese dioxide, a natural mineral), +7 (permanganate, such as KMnO4), +6 (manganate, such as K2MnO4) are stable oxidation states.

In an acidic solution, manganese of +3 valence, +5 valence and +6 valence of manganese are all prone to disproportionation reaction:

It is relatively stable, not easy to be oxidized, and not easy to be reduced. K2MnO4 and MnO2 have strong oxidizing properties. Mn(OH)2 is unstable and is easily oxidized by oxygen in the air to hydrated MnO2 [MnO(OH)2] Even a trace amount of dissolved oxygen in water can oxidize it; K2MnO4 can also undergo disproportionation reaction, but the reaction is not as good as in acid. complete in solution.