Manganese(II) carbonate

Manganese carbonate is a compound with the chemical formula MnCO3. Manganese carbonate occurs naturally as the mineral rhodochrosite but it is typically produced industrially. It is a pale pink, water-insoluble solid. Approximately 20,000 metric tonnes were produced in 2005.[3]

Manganese(II) carbonate
Names
IUPAC name
Manganese(II) carbonate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.009.040
EC Number
  • 209-942-9
UNII
  • InChI=1S/CH2O3.Mn/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 checkY
    Key: XMWCXZJXESXBBY-UHFFFAOYSA-L checkY
  • InChI=1/CH2O3.Mn/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2
    Key: XMWCXZJXESXBBY-NUQVWONBAJ
  • [Mn+2].[O-]C([O-])=O
Properties
MnCO3
Molar mass 114.95 g mol−1
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]
negligible
2.24 x 10−11
Solubility soluble in dilute acid, CO2
insoluble in alcohol, ammonia
+11,400·10−6 cm3/mol
1.597 (20 °C, 589 nm)
Structure
hexagonal-rhombohedral
Thermochemistry
94.8 J/mol·K[2]
109.5 J/mol·K[2]
-881.7 kJ/mol[2]
-811.4 kJ/mol[2]
Hazards
Flash point Non-flammable
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Structure and production

MnCO3 adopts a structure like calcite, consisting of manganese(II) ions in an octahedral coordination geometry.[4]

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.

Pink rhodochrosite, the mineral form of MnCO3, is of practical value as well as sought by collectors.

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, i.e. calcining, at 200 °C to give MnO1.88:

MnCO3 + 0.44 O2 → MnO1.8 + CO2

This method is sometimes employed in the production of manganese dioxide, which is used in 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.[5]

It is used in medicine as a hematinic.

Toxicity

Manganese poisoning, also known as manganism, may be caused by long-term exposure to manganese dust or fumes.

See also

References
  1. Sigma-Aldrich Co., Manganese(II) carbonate. Retrieved on 2014-05-06.
  2. "Manganese(II) carbonate".
  3. Arno H. Reidies (2007). "Manganese Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a16_123. ISBN 978-3527306732.
  4. Pertlik, F. (1986). "Structures of hydrothermally synthesized cobalt(II) carbonate and nickel(II) carbonate". Acta Crystallographica Section C. 42: 4–5. doi:10.1107/S0108270186097524.
  5. "How To Stain Concrete with Manganese"
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