Oxidizing

European Union chemical risk symbol for oxidant agents.

Generic label of dangerous goods for oxidant agents.

An oxidizing agent or oxidizing agent is a chemical compound that oxidizes another substance in electrochemical or reduction-oxidation reactions. In these reactions, the oxidizing compound is reduced.

Basically:

• The oxidant reduces, win electrons.
• The reducer oxidizedHe loses electrons.
• All reaction components have a state of oxidation.
• In these reactions a electron exchange.

Electron acceptors

Tetracianoquinodimetano is an organic electron acceptor.

Electron acceptors participate in electron transfer reactions. In this context, the oxidizing agent is called the electron acceptor and the reducing agent is called the electron donor. A classical oxidizing agent is the ion ferrocenium Fe(C
5H
5)+
2, which accepts an electron to form Fe(C₅H₅)₂. One of the strongest commercially available acceptors is "Magic blue", the radical cation derived from N(C₆H₄-4-Br)₃.

Extensive classification tabulations of the electron accepting properties of various reactants (redox potentials) are available.

Example of redox reaction

The formation of iron oxide is a classic redox reaction:

4Fe(s)+3O2(g)→ → 2Fe2O3(s){displaystyle 4Fe(s)+3O_{2}(g)to 2Fe_{2}O_{3}(s)}

In the above equation, the iron (Fe) atom has an oxidation number 0 and at the end of the reaction its oxidation number is +3. The oxygen atom starts with an oxidation number 0 and at the end its oxidation number is -2. The above reactions can be understood as two simultaneous half-reactions:

1. oxidation semi-reaction: 4Fe(s)→ → 2Fe2O3(s)+12e− − {displaystyle 4Fe(s)to 2Fe_{2}O_{3}(s)+12e^{-}}
2. Semi-reaction reduction: 3O2(g)+12e− − → → 2Fe2O3(s){displaystyle 3O_{2}(g)+12e^{-}to 2Fe_{2}O_{3}(s)}}

Iron(II) has oxidized because its oxidation number has increased and it acts as a reducing agent, transferring electrons to oxygen, which decreases its oxidation number (reduces) by accepting electrons from the metal.

Alternative meanings

Because the oxidation reaction is so widespread (explosives, chemical synthesis, corrosion), the term oxidant has come to acquire multiple meanings.

In one definition, the oxidant receives electrons from a reactant. In this context, the oxidant is called an electron acceptor. A classical oxidant is the ferrocenium ion [Fe(C₅H₅)₂]⁺, which can accept an electron and become ferrocene Fe(C₅H₅)₂. The electron transfer mechanism is of great interest, and can be described as internal or external sphere.

In another more colloquial meaning, the oxidant transfers oxygen atoms to the substrate. In this context, the oxidant can be described as an oxygenating agent or an oxygen atom transfer agent. Some examples are the permanganate anion MnO₄^-, the chromate CrO₄^- and osmium tetroxide, OsO ₄. Note that all these compounds are oxides, more specifically polyoxides. In some cases, these oxides can be used as electron acceptors, such as in the conversion reaction of permanganate MnO₄^- to manganate MnO₄^2-.

Oxidizing in combustion

In combustion, the oxidizer is also called oxidizer. An oxidizer is any substance that under certain conditions of temperature and pressure can combine with a fuel, thus causing combustion. It works by oxidizing the fuel and therefore being reduced by the latter.

The oxidizer par excellence is atmospheric oxygen, O₂ , or dioxygen, which is normally found in air with an approximate volume percentage concentration of 21%. All oxidizers have available oxygen in their composition, either in the form of molecular oxygen, as has been said, or as oxygen released at the time of combustion.

For combustion to occur, the presence of a minimum proportion of dioxygen is necessary, which as a general rule ranges from 15% to, in extreme cases, 5%.

In situations where there is no atmospheric oxygen, or where a very strong and energetic combustion is desired, gaseous or liquid dioxygen can be used, as in the case of rockets used in space shuttles, or various types of compound oxidizers. For example, in the combustion of gunpowder inside a cartridge, oxygen is supplied by a salt of an oxyacid, such as potassium nitrate or potassium chlorate.

The term oxidizer is used by extension to any medium in which ignition or combustion is possible,^{[citation needed]} being one of the sides of the Ostwald diagram.

Common oxidizing agents

• Hypochlorite and other hypohalites such as bleach.
• Diyodo and other halogens.
• Chlorine, chlorate, perchlorate and analogous halogen compounds.
• Permanganate salts, like potassium permanganate (KMnO)₄).
• Compounds related to the cerium (IV).
• Hexavalent chromium compounds, such as chromium acid, dichotomous acid and chromium trioxide, pyridinium chlorochromate (PCC) and chromat/dromats.
• Peroxides, like hydrogen peroxide (H)₂O₂or oxygenated water.
• Tollens reagent.
• Sulfoxides.
• Peroxo sulfuric acid.
• Ozone.
• Osmium tetroxide (OsO₄).
• Lead dioxide (PbO)₂).

Oxidizing agents and their oxidation products