Disproportionation

In <a href="/facts/Chemistry/SrNqkGVm">chemistry</a>, disproportionation, sometimes called dismutation, is a <a href="/facts/Redox_reaction/Pyd5RVcj">redox reaction</a> in which one compound of intermediate <a href="/facts/Oxidation_state/W53W6s6V">oxidation state</a> converts to two compounds, one of higher and one of lower oxidation state. The reverse of disproportionation, such as when a compound in an intermediate oxidation state is formed from precursors of lower and higher oxidation states, is called <a href="/facts/Comproportionation/XomX78yC">comproportionation</a>, also known as symproportionation.
More generally, the term can be applied to any desymmetrizing reaction where two molecules of one type react to give one each of two different types:

2 A → A' + A"
This expanded definition is not limited to redox reactions, but also includes some <a href="/facts/Molecular_autoionization/o7EBIQyP">molecular autoionization</a> reactions, such as the <a href="/facts/Self-ionization_of_water/xnjj2lQK">self-ionization of water</a>. In contrast, some authors use the term <a href="/facts/Redistribution_(chemistry)/pdbYLmRB">redistribution</a> to refer to reactions of this type (in either direction) when only ligand exchange but no redox is involved and distinguish such processes from disproportionation and comproportionation.For example, the <a href="/facts/Schlenk_equilibrium/FClagJIW">Schlenk equilibrium</a>

2 RMgX → R2Mg + MgX2
is an example of a redistribution reaction.

Disproportionation open-in-new

Disproportionation