Oxidizing agent
In chemistry, an oxidising agent is a substance that has the ability to oxidize other substances — in other words to accept their electrons. Common oxidizing agents are oxygen, hydrogen peroxide and the halogens.
In one sense, an oxidizing agent is a chemical species that undergoes a chemical reaction in which it gains one or more electrons. In that sense, it is one component in an oxidation–reduction reaction. In the second sense, an oxidizing agent is a chemical species that transfers electronegative atoms, usually oxygen, to a substrate. Combustion, many explosives, and organic redox reactions involve atom-transfer reactions.
Electron acceptors
Electron acceptors participate in electron-transfer reactions. In this context, the oxidizing agent is called an electron acceptor and the reducing agent is called an electron donor. A classic oxidizing agent is the ferrocenium ion, which accepts an electron to form Fe2. One of the strongest acceptors commercially available is "Magic blue", the radical cation derived from N3.Extensive tabulations of ranking the electron accepting properties of various reagents are available, see Standard electrode potential.
Atom-transfer reagents
In more common usage, an oxidising agent transfers oxygen atoms to a substrate. In this context, the oxidising agent can be called an oxygenation reagent or oxygen-atom transfer agent. Examples include , , OsO4, and especially . Notice that these species are all oxides.In some cases, these oxides can also serve as electron acceptors, as illustrated by the conversion of to, manganate.
Common oxidizing agents
- Oxygen
- Ozone
- Hydrogen peroxide and other inorganic peroxides, Fenton's reagent
- Fluorine, chlorine, and other halogens
- Nitric acid and nitrate compounds
- Sulfuric acid
- Peroxydisulfuric acid
- Peroxymonosulfuric acid
- Hypochlorite, Chlorite, chlorate, perchlorate, and other analogous halogen compounds like household bleach
- Hexavalent chromium compounds such as chromic and dichromic acids and chromium trioxide, pyridinium chlorochromate, and chromate/dichromate compounds
- Permanganate compounds such as potassium permanganate
- Sodium perborate
- Nitrous oxide, Nitrogen dioxide/Dinitrogen tetroxide
- Potassium nitrate, the oxidizer in black powder
- Sodium bismuthate
- Cerium compounds such as ceric ammonium nitrate and ceric sulfate
- Lead dioxide
Dangerous materials definition
The U.S. Department of Transportation defines oxidizing agents specifically. There are two definitions for oxidizing agents governed under DOT regulations. These two are Class 5; Division 5.11 and Class 5; Division 5.12. Division 5.1 "means a material that may, generally by yielding oxygen, cause or enhance the combustion of other materials." Division 5.1 of the DOT code applies to solid oxidizers "if, when tested in accordance with the UN Manual of Tests and Criteria, its mean burning time is less than or equal to the burning time of a 3:7 potassium bromate/cellulose mixture." 5.12 of the DOT code applies to liquid oxidizers "if, when tested in accordance with the UN Manual of Tests and Criteria, it spontaneously ignites or its mean time for a pressure rise from 690 kPa to 2070 kPa gauge is less than the time of a 1:1 nitric acid /cellulose mixture."
Common oxidizing agents and their products
| Agent | Product |
| O2 oxygen | Various, including the oxides H2O and CO2 |
| O3 ozone | Various, including ketones, aldehydes, and H2O; see ozonolysis |
| F2 fluorine | F− |
| Cl2 chlorine | Cl− |
| Br2 bromine | Br− |
| I2 iodine | I−, |
| ClO− hypochlorite | Cl−, H2O |
| chlorate | Cl−, H2O |
| HNO3 nitric acid | NO nitric oxide NO2 nitrogen dioxide |
| SO2 sulfur dioxide | S sulfur |
| Hexavalent chromium CrO3 chromium trioxide chromate dichromate | Cr3+, H2O |
| permanganate manganate | Mn2+ or MnO2 |
| ruthenium tetroxide osmium tetroxide | in organic lab scale synthesis |
| H2O2, other peroxides | Various, including oxides and H2O |
| Tl thallic compounds | Tl thallous compounds, in organic lab scale synthesis |