Manganese(II,III) oxide
| Names | |
|---|---|
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IUPAC name
manganese(II) dimanganese(III) oxide
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| Other names
Manganese tetroxide; Manganese oxide, Manganomanganic oxide, Trimanganese tetraoxide, Trimanganese tetroxide
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| Identifiers | |
| ECHA InfoCard | 100.013.879 |
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PubChem CID
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| RTECS number | OP0895000 |
| Properties | |
| Mn3O4 MnO.Mn2O3 |
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| Molar mass | 228.812 g/mol |
| Appearance | brownish-black powder |
| Density | 4.86 g/cm3 |
| Melting point | 1,567 °C (2,853 °F; 1,840 K) |
| Boiling point | 2,847 °C (5,157 °F; 3,120 K) |
| insoluble | |
| Solubility | soluble in HCl |
| +12,400·10−6 cm3/mol | |
| Hazards | |
| US health exposure limits (NIOSH): | |
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PEL (Permissible)
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C 5 mg/m3 |
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REL (Recommended)
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None established |
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IDLH (Immediate danger)
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N.D. |
| Thermochemistry | |
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Std molar
entropy (S |
149 J·mol−1·K−1 |
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Std enthalpy of
formation (ΔfH |
−1387 kJ·mol−1 |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is   ?) |
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| Infobox references | |
MnO.Mn2O3
Manganese(II,III) oxide is the chemical compound with formula Mn3O4. Manganese is present in two oxidation states +2 and +3 and the formula is sometimes written as MnO.Mn2O3. Mn3O4 is found in nature as the mineral hausmannite.
Mn3O4 formed when any manganese oxide is heated in air above 1000 °C. Considerable research has centred on producing nano-crystalline Mn3O4 and various syntheses that involve oxidation of MnII or reduction of MnVI.
Mn3O4 has been found to act as a catalyst for a range of reactions e.g. the oxidation of methane and carbon monoxide; the decomposition of NO, the reduction of nitrobenzene and the catalytic combustion of organic compounds.
Mn3O4 has the spinel structure, where the oxide ions are cubic close packed and the MnII occupy tetrahedral sites and the MnIII octahedral sites. The structure is distorted due to a Jahn-Teller effect. At room temperature Mn3O4 is paramagnetic, below 41-43 K, it is ferrimagnetic although this has been reported as reducing in nano-crystalline samples to around 39 K.
Mn3O4 is sometimes used as a starting material in the production of soft ferrites e.g. manganese zinc ferrite, and lithium manganese oxide, used in lithium batteries.
Manganese tetraoxide can also be used as a weighting agent while drilling reservoir sections in oil and gas wells.
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