Manganese(III) oxide
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| Names | |
|---|---|
| Other names
dimanganese trioxide, manganese sesquioxide, manganic oxide | |
| Identifiers | |
1317-34-6  | |
| 3D model (Jmol) | Interactive image |
| ChemSpider | 14139  |
| ECHA InfoCard | 100.013.878 |
| PubChem | 14824 |
| RTECS number | OP915000 |
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| 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] |
| Hazards | |
| NFPA 704 | |
| 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
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 Néel temperature of 39 K.[11]
References
- ↑ Otto H.H.; Baltrasch R.; Brandt H.J. (1993). "Further evidence for Tl3+ in Tl-based superconductors from improved bond strength parameters involving new structural data of cubic Tl2O3". Physica C. 215: 205. doi:10.1016/0921-4534(93)90382-Z.
- 1 2 Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A22. ISBN 0-618-94690-X.
- 1 2 3 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
- ↑ Shuijin Lei; Kaibin Tang; Zhen Fang; Qiangchun Liu; Huagui Zheng (2006). "Preparation of α-Mn2O3 and MnO from thermal decomposition of MnCO3 and control of morphology". Materials Letters. 60: 53. doi:10.1016/j.matlet.2005.07.0.
- ↑ Zhong-Yong Yuan; Tie-Zhen Ren; Gaohui Du; Bao-Lian Su (2004). "A facile preparation of single-crystalline α-Mn2O3 nanorods by ammonia-hydrothermal treatment of MnO2". Chemical Physics Letters. 389: 83. doi:10.1016/j.cplett.2004.03.064.
- ↑ Navin Chandra, Sanjeev Bhasin, Meenakshi Sharma and Deepti Pal (2007). "A room temperature process for making Mn2O3 nano-particles and γ-MnOOH nano-rods". Materials Letters. 61 (17): 3728. doi:10.1016/j.matlet.2006.12.024.
- ↑ Thomas Kohler; Thomas Armbruster; Eugen Libowitzky (1997). "Hydrogen Bonding and Jahn-Teller Distortion in Groutite,α-MnOOH, and Manganite,γ-MnOOH, and Their Relations to the Manganese Dioxides Ramsdellite and Pyrolusite". Journal of Solid State Chemistry. 133 (2): 486–500. doi:10.1006/jssc.1997.7516.
- 1 2 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
- ↑ Geller S. (1971). "Structure of α-Mn2O3, (Mn0.983Fe0.017)2O3 and (Mn0.37Fe0.63)2O3 and relation to magnetic ordering". Acta Crystallogr B. 27 (4): 821. doi:10.1107/S0567740871002966.
- ↑ Kim S. H; Choi B. J; Lee G.H.; Oh S. J.; Kim B.; Choi H. C.; Park J; Chang Y. (2005). "Ferrimagnetism in γ-Manganese Sesquioxide (γ−Mn2O3) Nanoparticles". Journal of the Korean Physical Society. 46 (4): 941.