Manganese(II) carbonate

Manganese carbonate is a compound with the chemical formula MnCO3. Manganese carbonate occurs naturally as the mineral rhodochrosite. Approximately 20M kg/y were produced in 2005.

Production and uses
Treatment of aqueous solutions of manganese(II) salts with alkali metal carbonates leads to precipitation of this faintly pink solid. The carbonate is insoluble in water but, like most carbonates, hydrolyses upon treatment with acids to give water-soluble salts.

Manganese carbonate decomposes with release of carbon dioxide at 200 °C to give manganese(II) oxide:
 * MnCO3  →   MnO  +  CO2

This method is sometimes employed in the production of manganese dioxide for dry-cell batteries and for ferrites.

Manganese carbonate is widely used as an additive to plant fertilizers to cure manganese deficient crops. It is also used in health foods, in ceramics as a glaze colorant and flux, and in concrete stains.

Toxicity
Manganese is essential for aerobic life and its compounds are not highly toxic. Manganese poisoning, also known as manganism, may be caused by long-term exposure to manganese dust or fumes.