Potassium hypomanganate
Potassium hypomanganate is the inorganic compound with the formula K3MnO4. Also known as potassium manganate(V), this bright blue solid is a rare example of a salt with the hypomanganate or manganate(V) anion, where the manganese atom is in the +5 oxidation state.
| Names | |
|---|---|
| IUPAC names
potassium manganate(V) potassium tetraoxidomanganate(3−) | |
| Identifiers | |
| Properties[1] | |
| K3MnO4 | |
| Molar mass | 236.23 g mol−1 |
| Appearance | bright blue solid |
| UV-vis (λmax) | 670 nm (ε = 900 dm3 mol−1 cm−1) |
| Related compounds | |
Other anions |
Potassium manganate Potassium permanganate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
Preparative routes
- by two-electron reduction of potassium permanganate with excess potassium sulfite;[2][3]
- MnO−
4 + SO2−
3 + H2O → MnO3−
4 + SO2−
4 + 2 H+
- MnO−
- by the single-electron reduction of potassium manganate with hydrogen peroxide in 10 M potassium hydroxide solution;[4]
- 2 MnO2−
4 + H2O2 + 2 OH− → 2 MnO3−
4 + O2 + 2 H2O
- 2 MnO2−
- by the single-electron reduction of potassium manganate with mandelate in 3–10 M potassium hydroxide solution;[1]
- 2 MnO2−
4 + C
8H
7O−
3 + 2 OH− → 2 MnO3−
4 + C
8H
5O−
3 + 2 H2O
- 2 MnO2−
- by disproportionation when manganese dioxide is dissolved in a concentrated solution of potassium hydroxide;[2]
- 2 MnO2 + 3 OH− → MnO3−
4 + MnOOH + H2O
- 2 MnO2 + 3 OH− → MnO3−
The compound is unstable due to the tendency of the hypomanganate anion to disproportionate in all but the most alkaline solutions.[2][3]
References
- Lee, Donald G.; Chen, Tao (1993), "Reduction of manganate(VI) by mandelic acid and its significance for development of a general mechanism of oxidation of organic compounds by high-valent transition metal oxides", J. Am. Chem. Soc., 115 (24): 11231–36, doi:10.1021/ja00077a023.
- Cotton, F. Albert; Wilkinson, Geoffrey (1980), Advanced Inorganic Chemistry (4th ed.), New York: Wiley, p. 746, ISBN 0-471-02775-8.
- Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. pp. 1221–22. ISBN 978-0-08-022057-4..
- Lee, Donald G.; Chen, Tao (1989), "Oxidation of hydrocarbons. 18. Mechanism of the reaction between permanganate and carbon-carbon double bonds", J. Am. Chem. Soc., 111 (19): 7534–38, doi:10.1021/ja00201a039.
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