Manganese(II) oxide
Names | |
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IUPAC name
Manganese(II) oxide
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Other names | |
Identifiers | |
ECHA InfoCard
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100.014.269 |
PubChem CID
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RTECS number
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
MnO | |
Molar mass | 70.9374 g/mol |
Appearance | green crystals or powder |
Density | 5.43 g/cm3 |
Melting point | 1,945 °C (3,533 °F; 2,218 K) |
insoluble | |
Solubility | soluble in acid |
+4850.0·10−6 cm3/mol | |
Refractive index (nD)
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2.16 |
Structure | |
Halite (cubic), cF8 | |
Fm3m, No. 225 | |
Octahedral (Mn2+); octahedral (O2−) | |
Thermochemistry | |
Std molar
entropy (S⦵298) |
60 J·mol−1·K−1[1] |
Std enthalpy of (ΔfH⦵298)formation |
−385 kJ·mol−1[1] |
Hazards | |
NFPA 704 (fire diamond) | |
Flash point | Non-flammable |
Related compounds | |
Other anions
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Manganese(II) fluoride Manganese(II) sulfide Manganese(II) selenide Manganese(II) telluride |
Other cations
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Iron(II) oxide |
Manganese(II,III) oxide Manganese(III) oxide Manganese dioxide Manganese heptoxide | |
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) oxide is an
Structure, stoichiometry, reactivity
Like many monoxides, MnO adopts the
Below 118 K MnO is antiferromagnetic.[3] MnO has the distinction of being one of the first compounds[4] to have its magnetic structure determined by neutron diffraction, the report appearing in 1951.[5] This study showed that the Mn2+ ions form a face centered cubic magnetic sub-lattice where there are ferromagnetically coupled sheets that are anti-parallel with adjacent sheets.
Manganese(II) oxide undergoes the chemical reactions typical of an ionic oxide. Upon treatment with acids, it converts to the corresponding manganese(II) salt and water.[3] Oxidation of manganese(II) oxide gives manganese(III) oxide.
Preparation and occurrence
MnO occurs in nature as the rare mineral manganosite.
It is prepared commercially by reduction of MnO2 with hydrogen, carbon monoxide or methane, e.g.:[2]
- MnO2 + H2 → MnO + H2O
- MnO2 + CO → MnO + CO2
Upon heating to 450 °C, manganese(II) nitrate gives a mixture of oxides, MnO2-x, which can be reduced to the monoxide with hydrogen at ≥750 °C.[6] MnO is particularly stable and resists further reduction.[7] MnO can also be prepared by heating the carbonate:[8]
- MnCO3 → MnO + CO2
This
An alternative route, mostly for demonstration purposes, is the oxalate method, which also applicable to the synthesis of
- MnC2O4·2H2O → MnO + CO2 + CO + 2 H2O
Applications
Together with manganese sulfate, MnO is a component of
References
- ^ ISBN 978-0-618-94690-7.
- ^
- ^ ISBN 978-0-08-037941-8.
- ISBN 0-471-93620-0
- ISSN 0031-899X.
- ^ H. Lux (1963). "Manganeses(II) Oxide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2pages=1455. NY, NY: Academic Press.
- ISBN 3527306730.
- ISBN 0-471-93620-0
- ^ Arthur Sutcliffe (1930) Practical Chemistry for Advanced Students (1949 Ed.), John Murray - London.