The chemogenesis analysis identifies five distinct types of reaction chemistry and one of these is redox chemistry. This page explores the different types of oxidation and reduction reaction behaviour that lie behind the easily memorised: OIL RIG mnemonic: Oxidation Is [electron] Loss & Reduction Is [electron] Gain.

Introduction to Redox Chemistry

Redox chemistry is concerned with net electron flow to and from a defined centre during a chemical reaction. A defined centre may be an atom, an elemental ion, a specific atom in a molecule, a specific atom in a molecular ion or a specific atom in a multifunctional molecule:


A defined centre is said to be oxidised if the electron density decreases, and reduced if electron density increases, during a reaction. The rule is:

Loss of electrons equates with Oxidation


Gain of electrons equates with Reduction

The oxidation of a defined centre can be changed in two ways.