Manganese(III) oxide
Names | |
---|---|
Other names
dimanganese trioxide, manganese sesquioxide, manganic oxide
|
|
Identifiers | |
1317-34-6 | |
Jmol 3D model | Interactive image |
PubChem | 14824 |
RTECS number | OP915000 |
|
|
Properties | |
Mn2O3 | |
Molar mass | 157.8743 g/mol |
Appearance | brown or black crystalline |
Density | 4.5 g/cm3 |
Melting point | 888 °C (1,630 °F; 1,161 K) (alpha form) 940 °C, decomposes (beta form) |
0.00504 g/100 mL (alpha form) 0.01065 g/100 mL (beta form) |
|
Solubility | insoluble in alcohol, acetone soluble in acid, ammonium chloride |
Structure | |
Cubic, cI80[1] | |
Ia-3, No. 206 | |
Thermochemistry | |
Std molar
entropy (S |
110 J·mol−1·K−1[2] |
Std enthalpy of
formation (ΔfH |
−971 kJ·mol−1[2] |
Vapor pressure | {{{value}}} |
Related compounds | |
Other anions
|
manganese trifluoride, manganese(III) acetate |
Other cations
|
chromium(III) oxide, iron(III) oxide |
Related compounds
|
manganese(II) oxide, manganese dioxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
|
verify (what is ?) | |
Infobox references | |
Manganese(III) oxide is a chemical compound with the formula Mn2O3.
Preparation and chemistry
Heating MnO2 in air at below 800 °C α-Mn2O3 is produced (higher temperatures produce Mn3O4).[3] γ-Mn2O3 can be produced by oxidation followed by dehydration of manganese(II) hydroxide.[3] Many preparations of nano-crystalline Mn2O3 have been reported, for example syntheses involving oxidation of MnII salts or reduction of MnO2.[4][5][6]
Manganese (III) oxide is formed by the redox reaction in an alkaline cell:
- 2 MnO2 + Zn → Mn2O3 + ZnO[citation needed]
Manganese (III) oxide Mn2O3 must not be confused with MnOOH manganese (III) oxyhydroxide. Contrary to Mn2O3, MnOOH is a compound that decomposes at about 300 °C to form MnO2.[7]
Structure
Mn2O3 is unlike many other transition metal oxides in that it does not adopt the corundum (Al2O3) structure.[3] Two forms are generally recognized, α-Mn2O3 and γ-Mn2O3,[8] although a high pressure form with the CaIrO3 structure has been reported too.[9]
α-Mn2O3 has the cubic bixbyite structure, which is an example of a C-type rare earth sesquioxide (Pearson symbol cI80, space group Ia3, #206). The bixbyite structure has been found to be stabilised by the presence of small amounts of Fe3+, pure Mn2O3 has an orthorhombic structure (Pearson symbol oP24,space group Pbca, #61).[10]
γ-Mn2O3 has a structure related to the spinel structure of Mn3O4 where the oxide ions are cubic close packed. This is similar to the relationship between γ-Fe2O3 and Fe3O4.[8] γ-Mn2O3 is ferrimagnetic with a Neel temperature of 39 K.[11]
References
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 3.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 8.0 8.1 Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
- ↑ High Pressure Phase transition in Mn2O3 to the CaIrO3-type Phase Santillan, J.; Shim, S. American Geophysical Union, Fall Meeting 2005, abstract #MR23B-0050
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- Articles without EBI source
- Chemical pages without ChemSpiderID
- Articles without KEGG source
- Articles without InChI source
- Articles without UNII source
- Pages using collapsible list with both background and text-align in titlestyle
- Chemical articles using a fixed chemical formula
- Articles with unsourced statements from August 2015
- Manganese compounds
- Oxides
- Manganese minerals
- Sesquioxides