Manganese(II) sulfate

Manganese(II) sulfate is the inorganic compound with the formula MnSO4. This colourless deliquescent solid is a commercially significant manganese(II) salt. Approximately 260M kg/y were produced worldwide in 2005. It is the precursor to manganese metal and many chemical compounds. Mn-deficient soil is remediated with this salt.

Like many metal sulfates, manganese sulfate forms a variety of hydrates: monohydrate, tetrahydrate, pentahydrate, heptahydrate. The monohydrate is most common. All of these salts are faintly pink. The pale color of Mn(II) salts is characteristic of high-spin complexes with the d5 configuration.

Applications and production
Typically manganese ores are purified by their conversion to manganese sulfate. Treatment of aqueous solutions of the sulfate with sodium carbonate leads to precipitation of manganese carbonate, which can be calcined to give the oxides MnOx. Manganese dioxide reacts with sulfur dioxide also affords manganese sulfate:
 * MnO2 +  SO2   →  MnSO4

Manganese sulfate is a by-product of various industrially significant oxidations that use manganese dioxide, including the manufacture of hydroquinone and anisaldehyde.

Treatment of manganese sulfate with potassium permanganate affords manganese dioxide, a component of dry-cell batteries.