Oxidizer Definition in Chemistry

What Is an Oxidizer?

This is the hazard symbol for oxidizers.
This is the hazard symbol for oxidizers.

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An oxidizer, also known as an oxidant or oxidizing agent, is a reactant that removes electrons from other reactants during a redox reaction. It may also be considered to be a chemical species that transfers electronegative atoms to a substrate. The word origin derives from the transfer of oxygen, but the definition has since been expanded to include other species in a redox reaction.

Oxidizer Examples

Hydrogen peroxide, ozone, and nitric acid are all oxidizers. The halogens are all excellent oxidizing agents. Naturally, oxygen (O2) and ozone (O3) are oxidizers.


  • Smith, Michael B.; March, Jerry (2007). Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.). New York: Wiley-Interscience. ISBN 0-471-72091-7.