1. Any chemical reaction of the type D01799-0.png, where A, A' and A'' are different chemical species. For example:
    The reverse of disproportionation is called @C01217@. A special case of disproportionation (or 'dismutation') is 'radical disproportionation', exemplified by:
    Reactions of the more general type:
    are also loosely described as radical disproportionations.
    PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1107 [Terms] [Paper]
  2. A @R05379@ or @I03258@ in which species with the same @O04365@ combine to yield one of higher @O04365@ and one of lower @O04365@. Example: D01799-4.png The term also applies to an internal @O04362@-reduction process as occurs, for example, among the iron atoms of CaFeO3, where D01799-5.png, at Fe subarrays on lowering the temperature.
    PAC, 1994, 66, 577. (Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)) on page 581 [Terms] [Paper]