Oxidizing agent
Overview
 
An oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...

. The oxidizing agent is reduced
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 and the reactant is oxidized in the process.

In simple terms:
  • The oxidizing agent is reduced.
  • The reducing agent is oxidized.
  • All atoms in a molecule can be assigned an oxidation number
    Oxidation number
    In coordination chemistry, the oxidation number of a central atom in a coordination compound is the charge that it would have if all the ligands were removed along with the electron pairs that were shared with the central atom. Oxidation numbers are often confused with oxidation states.The...

    . This number changes when an oxidant acts on a substrate.
  • Redox reactions occur when oxidation state
    Oxidation state
    In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...

    s
    of the reactants change.

The formation of iron(III) oxide;
4Fe + 3O2 → 2Fe2O3


In the above equation, the iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 (Fe) has an oxidation number of 0 before and 3+ after the reaction.
Encyclopedia
An oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...

. The oxidizing agent is reduced
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 and the reactant is oxidized in the process.

In simple terms:
  • The oxidizing agent is reduced.
  • The reducing agent is oxidized.
  • All atoms in a molecule can be assigned an oxidation number
    Oxidation number
    In coordination chemistry, the oxidation number of a central atom in a coordination compound is the charge that it would have if all the ligands were removed along with the electron pairs that were shared with the central atom. Oxidation numbers are often confused with oxidation states.The...

    . This number changes when an oxidant acts on a substrate.
  • Redox reactions occur when oxidation state
    Oxidation state
    In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...

    s
    of the reactants change.

Example of oxidation

The formation of iron(III) oxide;
4Fe + 3O2 → 2Fe2O3


In the above equation, the iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 (Fe) has an oxidation number of 0 before and 3+ after the reaction. For oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 (O) the oxidation number began as 0 and decreased to 2−. These changes can be viewed as two "half-reaction
Half-reaction
A half reaction is either the oxidation or reduction reaction component of a redox reaction. A half reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction.-Example:...

s" that occur concurrently:
  1. Oxidation half reaction: Fe0 → Fe3+ + 3e
  2. Reduction half reaction: O2 + 4e → 2 O2−


Iron (Fe) has become oxidized because its oxidation number increased and was the reducing agent because it gave electrons to the oxygen (O).
Oxygen (O) has been reduced because the oxidation number has decreased and is the oxidizing agent because it took electrons from iron (Fe).

Electron acceptor

Because the process of oxidation
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 is so widespread (fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....

, explosives, chemical synthesis
Chemical synthesis
In chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions...

, corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...

), the term oxidizing agent has acquired multiple meanings.

In one definition, an oxidizing agent accepts - or gains - electrons. In this context, the reducing agent is called an electron donor. A classic oxidizing agent is the ferrocenium
Ferrocene
Ferrocene is an organometallic compound with the formula Fe2. It is the prototypical metallocene, a type of organometallic chemical compound consisting of two cyclopentadienyl rings bound on opposite sides of a central metal atom. Such organometallic compounds are also known as sandwich compounds...

 ion [Fe(C5H5)2]+, which accepts an electron to form Fe(C5H5)2. Of great interest to chemist
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...

s are the details of the electron transfer
Electron transfer
Electron transfer is the process by which an electron moves from an atom or a chemical species to another atom or chemical species...

 event, which can be described as inner sphere or outer sphere.

In more colloquial usage, an oxidizing agent transfers oxygen atoms to the substrate. In this context, the oxidizing agent can be called an oxygenation reagent or oxygen-atom transfer agent. Examples include [MnO4] permanganate
Permanganate
A permanganate is the general name for a chemical compound containing the manganate ion, . Because manganese is in the +7 oxidation state, the permanganate ion is a strong oxidizing agent. The ion has tetrahedral geometry...

, [CrO4]2− chromate
Chromate
Chromate salts contain the chromate anion, CrO42−. Dichromate salts contain the dichromate anion, Cr2O72−. They are oxyanions of chromium in the oxidation state +6. They are moderately strong oxidizing agents.- Chemical properties :...

, OsO4 osmium tetroxide, and especially [ClO4] perchlorate
Perchlorate
Perchlorates are the salts derived from perchloric acid . They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders. They are used extensively within the pyrotechnics industry, and ammonium perchlorate is also a...

. Notice that these species are all oxide
Oxide
An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....

s, and are in fact polyoxides. In some cases, these oxides can also serve as electron acceptors, as illustrated by the conversion of [MnO4] to [MnO4]2−, manganate
Manganate
In inorganic nomenclature, a manganate is any negatively charged molecular entity with manganese as the central atom. However, the name is usually used to refer to the tetraoxidomanganate anion, MnO, also known as manganate because it contains manganese in the +6 oxidation state...

.

Dangerous materials definition

The dangerous materials definition of an oxidizing agent is a substance that is not necessarily combustible, but may, generally by yielding oxygen, cause or contribute to the combustion of other material (Australian Dangerous Goods Code, 6th Edition). 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.

Common oxidizing agents

  • Oxygen
    Oxygen
    Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

      (O2)
  • Ozone
    Ozone
    Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...

      (O3)
  • Hydrogen peroxide
    Hydrogen peroxide
    Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...

     (H2O2) and other inorganic peroxide
    Peroxide
    A peroxide is a compound containing an oxygen–oxygen single bond or the peroxide anion .The O−O group is called the peroxide group or peroxo group. In contrast to oxide ions, the oxygen atoms in the peroxide ion have an oxidation state of −1.The simplest stable peroxide is hydrogen peroxide...

    s
  • Fluorine
    Fluorine
    Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...

     (F2), chlorine
    Chlorine
    Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

     (Cl2), and other halogen
    Halogen
    The halogens or halogen elements are a series of nonmetal elements from Group 17 IUPAC Style of the periodic table, comprising fluorine , chlorine , bromine , iodine , and astatine...

    s
  • Nitric acid
    Nitric acid
    Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...

     (HNO3) and nitrate
    Nitrate
    The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...

     compounds
  • Sulfuric acid
    Sulfuric acid
    Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

      (H2SO4)
  • Persulfuric acids (H2SO5 and H2SO8)
  • Chlorite
    Chlorite
    The chlorite ion is ClO2−. A chlorite is a compound that contains this group,with chlorine in oxidation state +3. Chlorites are also known as salts of chlorous acid.-Oxidation states:...

    , chlorate
    Chlorate
    The chlorate anion has the formula ClO. In this case, the chlorine atom is in the +5 oxidation state. "Chlorate" can also refer to chemical compounds containing this anion; chlorates are the salts of chloric acid. "Chlorate", when followed by a roman numeral in parentheses, e.g...

    , perchlorate
    Perchlorate
    Perchlorates are the salts derived from perchloric acid . They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders. They are used extensively within the pyrotechnics industry, and ammonium perchlorate is also a...

    , and other analogous halogen
    Halogen
    The halogens or halogen elements are a series of nonmetal elements from Group 17 IUPAC Style of the periodic table, comprising fluorine , chlorine , bromine , iodine , and astatine...

     compounds
  • Hypochlorite
    Hypochlorite
    The hypochlorite ion, also known as chlorate anion is ClO−. A hypochlorite compound is a chemical compound containing this group, with chlorine in oxidation state +1.Hypochlorites are the salts of hypochlorous acid...

     and other hypohalite compounds, including household bleach
    Bleach
    Bleach refers to a number of chemicals that remove color, whiten, or disinfect, often via oxidation. Common chemical bleaches include household chlorine bleach , lye, oxygen bleach , and bleaching powder...

     (NaClO)
  • Hexavalent chromium
    Chromium
    Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...

     compounds such as chromic and dichromic acids and chromium trioxide
    Chromic acid
    The term chromic acid is usually used for a mixture made by adding concentrated sulfuric acid to a dichromate, which may contain a variety of compounds, including solid chromium trioxide. This kind of chromic acid may be used as a cleaning mixture for glass. Chromic acid may also refer to the...

    , pyridinium chlorochromate
    Pyridinium chlorochromate
    Pyridinium chlorochromate is a reddish orange solid reagent used to oxidize primary alcohols to aldehydes and secondary alcohols to ketones. Pyridinium chlorochromate, or PCC, will not fully oxidize a primary alcohol to the carboxylic acid as does the Jones reagent. A disadvantage to using PCC is...

     (PCC), and chromate/dichromate
    Chromate
    Chromate salts contain the chromate anion, CrO42−. Dichromate salts contain the dichromate anion, Cr2O72−. They are oxyanions of chromium in the oxidation state +6. They are moderately strong oxidizing agents.- Chemical properties :...

     compounds
  • Permanganate
    Permanganate
    A permanganate is the general name for a chemical compound containing the manganate ion, . Because manganese is in the +7 oxidation state, the permanganate ion is a strong oxidizing agent. The ion has tetrahedral geometry...

     compounds
  • Sodium perborate
    Sodium perborate
    Sodium perborate is a white, odorless, water-soluble chemical compound with the chemical composition 3. It crystallizes as the monohydrate, NaBO3·H2O, trihydrate, NaBO3·3H2O and tetrahydrate, NaBO3·4H2O. The monohydrate and tetrahydrate are the commercially important forms...

  • Nitrous oxide
    Nitrous oxide
    Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...

     (N2O)
  • Silver oxide  (Ag2O)
  • Osmium tetroxide (OsO4)
  • Tollens' reagent
    Tollens' reagent
    Tollens' reagent is a chemical reagent most commonly used to determine whether a known carbonyl-containing compound is an aldehyde or a ketone. It is usually ammoniacal silver nitrate, but can also be other mixtures, as long as aqueous diamminesilver complex is present...

  • 2,2'-Dipyridyldisulfide
    2,2'-Dipyridyldisulfide
    2,2'-Dipyridyldisulfide, sometimes known as DPS, is used for preparing thiols and activating or protecting carboxylic acid with triphenylphosphine in the following reaction.-Uses:...

     (DPS)

Common oxidizing agents and their products

Agent Product(s)
O2 oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

Various, including the oxides H2O and CO2
O3 ozone
Ozone
Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...

Various, including ketones, aldehydes, and H2O; see ozonolysis
Ozonolysis
Ozonolysis is the cleavage of an alkene or alkyne with ozone to form organic compounds in which the multiple carbon–carbon bond has been replaced by a double bond to oxygen...

F2 fluorine
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...

F
Cl2 chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

Cl
Br2 bromine
Bromine
Bromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...

Br
I2 iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....

I, I3
OCl hypochlorite
Hypochlorite
The hypochlorite ion, also known as chlorate anion is ClO−. A hypochlorite compound is a chemical compound containing this group, with chlorine in oxidation state +1.Hypochlorites are the salts of hypochlorous acid...

Cl, H2O
ClO3 chlorate
Chlorate
The chlorate anion has the formula ClO. In this case, the chlorine atom is in the +5 oxidation state. "Chlorate" can also refer to chemical compounds containing this anion; chlorates are the salts of chloric acid. "Chlorate", when followed by a roman numeral in parentheses, e.g...

Cl, H2O
HNO3 nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...

NO nitric oxide
Nitric oxide
Nitric oxide, also known as nitrogen monoxide, is a diatomic molecule with chemical formula NO. It is a free radical and is an important intermediate in the chemical industry...


NO2 nitrogen dioxide
Nitrogen dioxide
Nitrogen dioxide is the chemical compound with the formula it is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...

Hexavalent chromium
CrO3 chromium trioxide
Chromium trioxide
Chromium trioxide is the inorganic compound with the formula CrO3. It is the acidic anhydride of chromic acid, and is sometimes marketed under the same name.This compound is a dark-red/orange brown solid, which dissolves in water concomitant with hydrolysis...


CrO42− chromate
Chromate
Chromate salts contain the chromate anion, CrO42−. Dichromate salts contain the dichromate anion, Cr2O72−. They are oxyanions of chromium in the oxidation state +6. They are moderately strong oxidizing agents.- Chemical properties :...

 
Cr2O72− dichromate
Cr3+, H2O
MnO4 permanganate
Permanganate
A permanganate is the general name for a chemical compound containing the manganate ion, . Because manganese is in the +7 oxidation state, the permanganate ion is a strong oxidizing agent. The ion has tetrahedral geometry...


MnO42− manganate
Manganate
In inorganic nomenclature, a manganate is any negatively charged molecular entity with manganese as the central atom. However, the name is usually used to refer to the tetraoxidomanganate anion, MnO, also known as manganate because it contains manganese in the +6 oxidation state...

Mn2+ (acidic) or MnO2 (basic)
H2O2, other peroxide
Peroxide
A peroxide is a compound containing an oxygen–oxygen single bond or the peroxide anion .The O−O group is called the peroxide group or peroxo group. In contrast to oxide ions, the oxygen atoms in the peroxide ion have an oxidation state of −1.The simplest stable peroxide is hydrogen peroxide...

s
Various, including oxides and H2O
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