Editing Oxidizing agent

{{short description|Chemical compound used to oxidize another substance in a chemical reaction}}
{{Use mdy dates|date=November 2020}}
{{Use American English|date=November 2020}}
[[File:GHS-pictogram-rondflam.svg|thumb|125px|The [[Globally Harmonized System of Classification and Labeling of Chemicals|international]] [[GHS hazard pictograms|pictogram]] for oxidizing chemicals.]]
[[Image:DOT hazmat class 5.1.svg|thumb|125px|[[Dangerous goods]] label for oxidizing agents]]

An '''oxidizing agent''' (also known as an '''oxidant''', '''oxidizer''', '''electron recipient''', or '''electron acceptor''') is a substance in a [[redox]] chemical reaction that gains or "[[Electron acceptor|accepts]]"/"receives" an [[electron]] from a {{em|[[reducing agent]]}} (called the {{em|reductant}}, {{em|reducer}}, or ''electron donor''). In other words, an oxidizer is any substance that [[oxidize]]s another substance. The [[oxidation state]], which describes the degree of loss of [[electrons]], of the oxidizer decreases while that of the reductant increases; this is expressed by saying that oxidizers "undergo reduction" and "are reduced" while reducers "undergo oxidation" and "are oxidized".
Common oxidizing agents are [[oxygen]], [[hydrogen peroxide]], and the [[halogen]]s.

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 [[Redox|oxidation–reduction]] (redox) 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 reaction]]s involve atom-transfer reactions.

==Electron acceptors==
{{redox_example.svg}}
[[file:Tetracyanoquinodimethane Formula V.1.svg|thumb|right|100px|[[Tetracyanoquinodimethane]] is an organic electron-acceptor.]]
[[Electron acceptor]]s 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 tetrafluoroborate|ferrocenium]] ion {{chem|Fe(C|5|H|5|)|2|+}}, which accepts an electron to form Fe(C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>.  One of the strongest acceptors commercially available is "[[Magic blue]]", the radical cation derived from N(C<sub>6</sub>H<sub>4</sub>-4-Br)<sub>3</sub>.<ref name=Geiger>{{cite journal|author=N. G. Connelly, W. E. Geiger| title=Chemical Redox Agents for Organometallic Chemistry|journal=[[Chemical Reviews]]|year= 1996| volume= 96|issue=2| pages= 877–910| doi=10.1021/cr940053x| pmid=11848774}}</ref>

Extensive tabulations of ranking the electron accepting properties of various reagents (redox potentials) are available, see [[Standard electrode potential (data page)]].

==Atom-transfer reagents==
In more common usage, an oxidizing agent transfers oxygen atoms to a substrate. In this context, the oxidizing agent can be called an oxygenation reagent or oxygen-atom transfer (OAT) agent.<ref>{{March6th}}</ref> Examples include {{chem|MnO|4|-}} ([[permanganate]]), {{chem|CrO|4|2-}} ([[Chromate ion|chromate]]), OsO<sub>4</sub> ([[osmium tetroxide]]), and especially {{chem|ClO|4|-}} ([[perchlorate]]). Notice that these species are all [[oxide]]s.

In some cases, these oxides can also serve as electron acceptors, as illustrated by the conversion of {{chem|MnO|4|-}} to {{chem|MnO|4|2-}},ie [[permanganate]] to [[manganate]].

===Common oxidizing agents===
*[[Oxygen]] (O<sub>2</sub>)
*[[Ozone]] (O<sub>3</sub>)
*[[Hydrogen peroxide]] (H<sub>2</sub>O<sub>2</sub>) and other inorganic [[peroxide]]s, [[Fenton's reagent]]
*[[Fluorine]] (F<sub>2</sub>), [[chlorine]] (Cl<sub>2</sub>), and other [[halogen]]s
*[[Nitric acid]] (HNO<sub>3</sub>) and [[nitrate]] compounds such as [[potassium nitrate]] (KNO<sub>3</sub>), the oxidizer in [[black powder]]
*[[Potassium chlorate]] (KClO<sub>3</sub>) 
*[[Xenon difluoride]] (XeF<sub>2</sub>)
*[[Xenon tetrafluoride]] (XeF<sub>4</sub>)
*[[Xenon hexafluoride]] (XeF<sub>6</sub>)
*[[Krypton difluoride]] (KrF<sub>2</sub>)
*[[Sulfur]] (S<sub>8</sub>)
*[[Peroxydisulfuric acid]] (H<sub>2</sub>S<sub>2</sub>O<sub>8</sub>)
*[[Peroxymonosulfuric acid]] (H<sub>2</sub>SO<sub>5</sub>)
*[[Hypochlorite]], [[chlorite]], [[chlorate]], [[perchlorate]], and other analogous [[halogen]] oxyanions
*Fluorides of [[chlorine fluoride|chlorine]], [[bromine fluoride|bromine]], and [[iodine fluoride|iodine]]
*Hexavalent [[chromium]] compounds such as [[chromic acid|chromic and dichromic acids and chromium trioxide]], [[pyridinium chlorochromate]] (PCC), and [[Chromate and dichromate|chromate/dichromate]] compounds such as [[Sodium dichromate]] (Na<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>)
*[[Permanganate]] compounds such as [[potassium permanganate]] (KMnO<sub>4</sub>)
*[[Sodium perborate]] ({{chem|[|Na|+|]|2}}·{{chem|[|B|2|O|4|(|OH|)|4|]|2-}})
*[[Nitrous oxide]] (N<sub>2</sub>O), [[Nitrogen dioxide]]/[[Dinitrogen tetroxide]] (NO<sub>2</sub> / N<sub>2</sub>O<sub>4</sub>)
*[[Sodium bismuthate]] (NaBiO<sub>3</sub>)
*Cerium (IV) compounds such as [[ceric ammonium nitrate]] and [[ceric sulfate]]
*[[Lead dioxide]] (PbO<sub>2</sub>)

== Dangerous materials definition ==
{{See also|HAZMAT Class 5 Oxidizing agents and organic peroxides}}
The [[dangerous goods]] definition of an oxidizing agent is a substance that can cause or contribute to the combustion of other material.<ref>Australian Dangerous Goods Code, 6th Edition</ref> By this definition some materials that are classified as oxidizing agents by analytical chemists are not classified as oxidizing agents in a dangerous materials sense. An example is [[potassium dichromate]], which does not pass the dangerous goods test of an oxidizing agent.

The [[U.S. Department of Transportation]] defines oxidizing agents specifically. There are two definitions for oxidizing agents governed under DOT regulations. These two are [[HAZMAT Class 5 Oxidizing agents and organic peroxides|Class 5]]; Division 5.1(a)1 and Class 5; Division 5.1(a)2. Division 5.1 "means a material that may, generally by yielding oxygen, cause or enhance the combustion of other materials." Division 5.(a)1 of the DOT code applies to solid oxidizers "if, when tested in accordance with the UN Manual of Tests and Criteria (IBR, see § 171.7 of this subchapter), its mean burning time is less than or equal to the burning time of a 3:7 potassium bromate/cellulose mixture." 5.1(a)2 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 (65 percent)/cellulose mixture."<ref>49 CFR 172.127 General Requirements for Shipments and Packagings; Subpart D</ref>

==Common oxidizing agents and their products==

{| class="wikitable"
! Agent
! Product(s)
|-
|O<sub>2</sub> [[oxygen]]
|Various, including the oxides H<sub>2</sub>O and CO<sub>2</sub>
|-
|O<sub>3</sub> [[ozone]]
|Various, including ketones, aldehydes, and H<sub>2</sub>O; see [[ozonolysis]]
|-
|F<sub>2</sub> [[fluorine]]
|F<sup>−</sup>
|-
|Cl<sub>2</sub> [[chlorine]]
|Cl<sup>−</sup>
|-
|Br<sub>2</sub> [[bromine]]
|Br<sup>−</sup>
|-
|I<sub>2</sub> [[iodine]]
|I<sup>−</sup>, {{chem|I|3|−}}
|-ok
|ClO<sup>−</sup> [[hypochlorite]]
|Cl<sup>−</sup>, H<sub>2</sub>O
|-
|{{chem|ClO|3|−}} [[chlorate]]
|Cl<sup>−</sup>, H<sub>2</sub>O
|-
|HNO<sub>3</sub> [[nitric acid]]
|NO [[nitric oxide]] (Dilute nitric acid)<br/>NO<sub>2</sub> [[nitrogen dioxide]] (Concentrated nitric acid)
|-
|H<sub>2</sub>SO<sub>4</sub>(''l'') [[Sulfuric acid|Concentrated sulphuric acid]] 
SO<sub>3</sub> [[Sulfur trioxide|Sulphur trioxide]]
|SO<sub>2</sub> Sulphur dioxide (non-aqueous)
H<sub>2</sub>SO<sub>3</sub> [[Sulfurous acid|Sulphurous acid]] (In aqueous solution) 
|-
|SO<sub>2</sub> [[sulfur dioxide]]
|S [[sulfur]]<br/>([[Claus process]], [[ultramarine]] production, more commonly reducing agent)
|-
|Hexavalent chromium<br/>CrO<sub>3</sub> [[chromium trioxide]]<br/>{{chem|CrO|4|2−}} [[Chromate ion|chromate]] <br/>{{chem|Cr|2|O|7|2−}} [[dichromate]]
|Cr<sup>3+</sup>, H<sub>2</sub>O
|-
|{{chem|MnO|4|−}} [[permanganate]]<br/>{{chem|MnO|4|2−}} [[manganate]]
|Mn<sup>2+</sup> (acidic) or<br/>MnO<sub>2</sub> (basic)
|-
|Ag<sup>+</sup> ion [[Silver]] ion
|Ag (Metal)
|-
|SbF<sub>5</sub> [[antimony pentafluoride]]
|SbF<sub>6</sub><sup>−</sup> [[hexafluoroantimonate]] or SbF<sub>3</sub> [[antimony trifluoride]]
|-
|PtF<sub>6</sub> [[platinum hexafluoride]]
|PtF<sub>6</sub><sup>−</sup> [[hexafluoroplatinate]]
|-
|{{chem|RuO|4}} [[ruthenium tetroxide]]<br/>{{chem|OsO|4}} [[osmium tetroxide]]
|in organic lab scale synthesis
|-
|H<sub>2</sub>O<sub>2</sub>, other [[peroxide]]s
|Various, including oxides and H<sub>2</sub>O
|-
|Tl(III) [[Thallium|thallic]] compounds
|Tl(I) thallous compounds, in organic lab scale synthesis
|}

==See also==

* {{annotated link|Combustion}}
* {{annotated link|Electron acceptor}}
* {{annotated link|Electron donor}}
* {{annotated link|Electrosynthesis}}
* {{annotated link|Organic oxidation}}
* {{annotated link|Organic redox reaction}}
* {{annotated link|Reducing agent}}
* {{annotated link|Solvated electron}}

==References==
{{reflist}}

== External links ==
* {{Commons category-inline|Oxidizing agents}}

{{Authority control}}

[[Category:Oxidizing agents| ]]
[[Category:Chemical properties]]
[[Category:Electrochemistry]]
[[Category:Redox]]