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Incoming links: Electron transfer and ionic character
Redox Created 2026-10-13 Updated 2026-10-20
A redox chemical reaction couples oxidation and reduction. In the electrode examples here, oxidation releases electrons and reduction accepts them. [ref]
Chemistry 2e by Paul Flowers and others. §4.2, “Oxidation-Reduction Reactions”: paired electron loss and gain
Redox can be recognized by changes in oxidation state: an increase records oxidation, a decrease reduction. These are formal electron assignments, distinct from measured partial atomic charges. Half-reactions expose the matching loss and gain, making electric charge conservation visible.[ref]
Chemistry 2e by Paul Flowers and others. §4.2, “Oxidation-Reduction Reactions”: oxidation-number definition and complementary processes
The electron accounting need not describe free electrons travelling between spatially separated chemical species. For example, in , hydrogen changes from oxidation state to and oxygen from to . Four hydrogen chemical atoms lose four formally assigned electrons in total; two oxygen chemical atoms gain four. The water product has covalent bonds, and these assignments do not turn it into separated ions. See ionic approximation of bonds and electron transfer and ionic character.
By contrast, neutralization can rearrange chemical bonds without changing oxidation states:Hydrogen remains and oxygen remains . The aqueous proton notation abbreviates its interaction with water. This acid-base chemistry example conserves electric charge but has no matching increase and decrease of oxidation state; movement of ions or a change of chemical bonds alone does not establish redox.