Comproportionation: Difference between revisions
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Thecurran91 (talk | contribs) Added more info about frost diagrams, rewrote the intro for slightly better english |
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'''Symproportionation''' or '''comproportionation''' is a chemical reaction |
'''Symproportionation''' or '''comproportionation''' is a chemical reaction where two reactants, each containing the same element but with a different [[oxidation number]], will form a product with an oxidation number intermediate of the two reactants. For example, an element A in the oxidation states 0 and +2 can symproportionate to the state +1. It is opposite to [[disproportionation]], where two or more atoms of the same element originally having the same oxidation state react with other chemical(s) or themselves to give different oxidation numbers. |
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==Frost diagrams== |
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Examples: |
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{{main|Frost diagram}} |
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The tendency of two species to symproportionate can be determined by examining the [[Frost diagram]] of the oxidation states; if a species' value of ΔG/F is lower than the line joining the two oxidation numbers either side of it, then it is more stable than a solution of these two species and they will undergo symproportionation. |
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==Examples of symproportionation== |
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* In lead batteries, the spontaneous reaction is Pb(s) + PbO<sub>2</sub>(s) + 2 H<sub>2</sub>SO<sub>4</sub>(aq) -> 2 PbSO<sub>4</sub>(s) + 2 H<sub>2</sub>O(l). |
* In lead batteries, the spontaneous reaction is Pb(s) + PbO<sub>2</sub>(s) + 2 H<sub>2</sub>SO<sub>4</sub>(aq) -> 2 PbSO<sub>4</sub>(s) + 2 H<sub>2</sub>O(l). |
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* [[Potassium permanganate]] contains [[manganese]] with [[oxidation number]] of +7 and reacts with a manganese compound having oxidation number +2 to yield [[Manganese(IV) oxide]] (manganese dioxide) with oxidation number +4, [[potassium hydroxide]] and water. |
* [[Potassium permanganate]] contains [[manganese]] with [[oxidation number]] of +7 and reacts with a manganese compound having oxidation number +2 to yield [[Manganese(IV) oxide]] (manganese dioxide) with oxidation number +4, [[potassium hydroxide]] and water. |
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Revision as of 14:10, 21 March 2010
Symproportionation or comproportionation is a chemical reaction where two reactants, each containing the same element but with a different oxidation number, will form a product with an oxidation number intermediate of the two reactants. For example, an element A in the oxidation states 0 and +2 can symproportionate to the state +1. It is opposite to disproportionation, where two or more atoms of the same element originally having the same oxidation state react with other chemical(s) or themselves to give different oxidation numbers.
Frost diagrams
The tendency of two species to symproportionate can be determined by examining the Frost diagram of the oxidation states; if a species' value of ΔG/F is lower than the line joining the two oxidation numbers either side of it, then it is more stable than a solution of these two species and they will undergo symproportionation.
Examples of symproportionation
- In lead batteries, the spontaneous reaction is Pb(s) + PbO2(s) + 2 H2SO4(aq) -> 2 PbSO4(s) + 2 H2O(l).
- Potassium permanganate contains manganese with oxidation number of +7 and reacts with a manganese compound having oxidation number +2 to yield Manganese(IV) oxide (manganese dioxide) with oxidation number +4, potassium hydroxide and water.
- In chalcogen chemistry 15Se + SeCl4 + 4AlCl3 -> Na[AlCl]4 + 3Se8[AlCl4]2. [1]
- In volcanic eruptions, the redox reaction 2H2S(g) + SO2(g) -> 3S(s) + 2H2O(g).
References
- Translated from German Wiki original