Manganese(II) carbonate

Manganese(II) carbonate

Names
IUPAC name Manganese(II) carbonate
Identifiers
CAS Registry Number	598-62-9 Y
ChemSpider	11233 Y
EC number	209-942-9
InChI InChI=1S/CH2O3.Mn/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Y Key: XMWCXZJXESXBBY-UHFFFAOYSA-L Y InChI=1/CH2O3.Mn/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Key: XMWCXZJXESXBBY-NUQVWONBAJ
Jmol-3D images	Image
PubChem	11726
SMILES [Mn+2].[O-]C([O-])=O
UNII	9ZV57512ZM Y
Properties
Chemical formula	MnCO3
Appearance	White to faint pink solid
Density	3.12 g/cm3
Melting point	200–300 °C (392–572 °F; 473–573 K) decomposes[1][2]
Solubility in water	negligible
Solubility product (Ksp)	2.24 x 10−11
Solubility	soluble in dilute acid, CO2 insoluble in alcohol, ammonia
Refractive index (nD)	1.597 (20 °C, 589 nm)
Structure
Crystal structure	hexagonal-rhombohedral
Thermochemistry
Specific heat capacity (C)	94.8 J/mol·K[2]
Std molar entropy (So298)	109.5 J/mol·K[2]
Std enthalpy of formation (ΔfHo298)	-881.7 kJ/mol[2]
Gibbs free energy (ΔfG˚)	-811.4 kJ/mol[2]
Hazards
EU Index	Not listed
Flash point	Non-flammable
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Manganese carbonate is a compound with the chemical formula MnCO₃. Manganese carbonate occurs naturally as the mineral rhodochrosite. Approximately 20,000 metric tonnes were produced in 2005.^[3]

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.^[3]

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.^[4]

It is used in medicine as a hematinic.

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.

See also

• Manganese deficiency (medicine)

References