Manganese carbonate is a

compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with defensive struc ...

with the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbol ...

Mn CO₃. Manganese carbonate occurs naturally as the

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

rhodochrosite Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its (rare) pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. It streaks white, and its Mohs hardness varies bet ...

but it is typically produced industrially. It is a pale pink, water-insoluble solid. Approximately 20,000 metric tonnes were produced in 2005.

Structure and production

MnCO₃ adopts a structure like calcite, consisting of manganese(II) ions in an

octahedral coordination geometry In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The oc ...

. Treatment of aqueous solutions of manganese(II) nitrate with ammonia and carbon dioxide leads to precipitation of this faintly pink solid. The side product, ammonium nitrate is used as fertilizer.

Reactions and uses

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 Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

, i.e.

calcining Calcination refers to thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), gener ...

, at 200 °C to give MnO_1.88: :MnCO₃ + 0.44 O₂ → MnO_1.8 + CO₂ This method is sometimes employed in the production of manganese dioxide, which is used in 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 A colourant/colour additive (British spelling) or colorant/color additive (American spelling) is a substance that is added or applied in order to change the colour of a material or surface. Colourants can be used for many purposes including printing ...

and flux, and in concrete stains."How To Stain Concrete with Manganese"
/ref> It is used in medicine as a

hematinic A hematinic is a nutrient required for the formation of blood cells in the process of hematopoiesis. The main hematinics are iron, B12, and folate. Deficiency in hematinics can lead to anaemia. In cases of hematinic deficiency, hematinics can be ...

Toxicity

Manganese poisoning, also known as

manganism Manganism or manganese poisoning is a toxic condition resulting from chronic exposure to manganese. It was first identified in 1837 by James Couper. Signs and symptoms Chronic exposure to excessive manganese levels can lead to a variety of psyc ...

, may be caused by long-term exposure to manganese dust or fumes.

References

{{Manganese compounds Carbonates Manganese(II) compounds

Structure and production

Reactions and uses

Toxicity

See also

References