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| Names | |
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| Other names
Manganese dihydroxide, manganese hydroxide, Manganous hydroxide, Pyrochroite
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| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.126.826 |
| EC Number |
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PubChem CID
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CompTox Dashboard (EPA)
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| 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 |
Refractive index (nD)
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1.68 |
| Structure | |
| hexagonal | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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
- ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
- ^ 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.
