Disproportionation or dismutation's used to describe two particular types of chemical reaction: A chemical reaction of the type: 2A → A' + A" where A, A' and A" are different chemical species. While the most common type's a redox reaction, other types are possible. For example: 2H2O → H3O+ + OH-'s a disproportionation but isn't a redox reaction. A chemical reaction (reversible or irreversible) in which a species's simultaneously reduced and oxidized so as to form two different pro… (More on Dismutation)