Chemistry:Manganese(II) hydroxide

From HandWiki
Manganese(II) hydroxide
Names
Other names
Manganese dihydroxide, manganese hydroxide, Manganous hydroxide, Pyrochroite
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
EC Number
  • 606-171-3
Properties
H2MnO2
Molar mass 88.952 g·mol−1
Appearance white to pink solid
Density 3.258 g/cm3
Melting point 140 °C (284 °F; 413 K) decomposes
0.00034 g/100 mL at 18 °C.[1]
Solubility soluble in acid
1.68
Structure
hexagonal
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Manganese(II) hydroxide is the inorganic compound with the formula Mn(OH)2. It is a white solid although samples darken quickly upon exposure to air owing to oxidation. It is poorly soluble in water.

Preparation and reactions

Manganese(II) hydroxide precipitates as a solid when an alkali metal hydroxide is added to an aqueous solution of Mn2+ salt:[2]

Mn2+ + 2 NaOH → Mn(OH)2 + 2 Na+

Manganese(II) hydroxide oxidises readily in air, as indicated by darkening of samples.

The compound adopts the brucite structure, as do several other metal dihydroxides.

References

  1. Lide, David R., ed (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3. 
  2. H. Lux "Manganese(IV) Hydroxide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1456.