* The term corrosion refers to the electrochemical oxidation of metals in reaction with an oxidant such as oxygen. Rusting, the formation of iron oxides, is a well-known example of electrochemical corrosion: it forms as a result of the oxidation of iron metal. Common rust often refers to iron(III) oxide, formed in the following chemical reaction:
* The oxidation of iron(II) to iron(III) by hydrogen peroxide in the presence of an acid:
:Here the overall equation involves adding the reduction equation to twice the oxidation equation, so that the electrons cancel: