Science, Tech, Math › Science Oxidizer Definition in Chemistry What Is an Oxidizer? Share Flipboard Email Print This is the hazard symbol for oxidizers. Ingram Publishing, Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated May 08, 2019 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. Source Smith, Michael B.; March, Jerry (2007). Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.). New York: Wiley-Interscience. ISBN 0-471-72091-7.