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What is Peroxide?

Peroxides are defined as groups of compounds in which two oxygen atoms are joined together by a single covalent bond. They have the typical structure of R-O-O-R where R denotes any kind of atom. The O-O the bond present is called the peroxide group. Usually, the oxygen ion has a 2- oxidation number, but the oxygen atoms in the O-O bond has an oxidation number of 1-. Peroxides are unstable compounds and release oxygen when heated to decomposition. Thus, peroxides are strong oxidising agents. Peroxides can be formed by the direct reaction of an element with oxygen.

Hydrogen peroxide (H2O2) is the most common peroxide found. It is almost colourless and its solutions are colourless as well. It is very dangerous when it comes into contact with organic compounds. However, it is biochemically produced and synthesized inside our bodies as a result of the oxidase enzyme range.


There are a few major classes of peroxides:

  • Peroxy Acids: Peroxy derivatives of familiar acids, for example, peracetic acid,

  • Primary Group Peroxides: Compounds with the structure E-O-O-E where E is the main group element,

  • Metal Peroxides: The main element is a metal, for example, zinc peroxide (ZnO2),

  • Organic Peroxides: The main element is carbon and the main structure is C-O-O-C or C-O-O-H, for example, tertiary butyl hydroperoxide.


The most common peroxide is hydrogen peroxide (H2O2) which acts as a bleaching agent. Metallic class oxides which contain the divalent -O-O- bond are also considered peroxide. Na2O2 is one such example. It is also used as a bleaching agent. Organic compounds that contain the -O-O- bond or the peroxide anion are also considered peroxides. These kinds of compounds are explosive in nature. Ozone, ozonides and superoxides are also peroxides but tend to be ignored as peroxides due to their specific characteristics.

There are some compounds that resemble the peroxide formula but do not contain the -O-O- bond such as Manganese peroxide (MnO2). 


Peroxides have a wide range of purposes in everyday life as well as in our bodies. Inside our bodies, hydrogen peroxide is formed during some kind of biochemical process. Peroxides formed inside our bodies are called peroxisomes. Although it is formed momentarily, it is toxic to our cells, especially the DNA. This characteristic feature of hydrogen peroxide is useful for killing bacteria and pathogens inside our bodies. Peroxisomes are used in the synthesis of compounds that are important for the normal functioning of the brain and the lungs. They are also useful for the synthesis of fatty acids and polyamines.

Plants also use peroxides for signalling defence against pathogens.

Peroxides like hydrogen peroxide are used as bleaching agents and in hair products to lighten hair colour. Peroxides are also used to synthesize drugs and some other chemicals.

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FAQs on Peroxide

1. What is peroxide?

Peroxide are those chemical compounds that have two oxygen atoms linked by a covalent bond with each other. These oxygen molecules have an oxidation number '-1'. Peroxides are formed spontaneously by free radical reactions of hydrocarbons and molecular oxygen.

2. What are some examples of peroxides?

Peroxides are compounds with a structure R-O-O-R. Here R can be - hydrogen, carbon, metal etc.  The most common peroxide is Hydrogen peroxide (H2O2). There are also some other types of Peroxides present:

  • Metal peroxide as sodium peroxide (Na2O2), zinc peroxide (ZnO2),

  • Organic peroxide as tert-butyl-hydroperoxide, 

  • Peroxy acids as peroxy mono-sulfuric acid.

3. What are the uses of peroxides?

Peroxides have the following uses:

  1.  Peroxides are used as colourant and cleaning agents.

  2. In plants,  peroxides are used as signalling agents, and for defence purposes as well.

  3. In the human liver cell, detoxification is done by catalase enzymes which use peroxides for oxidation of the substrates.

  4. In Drug synthesis peroxides are used

  5. Bombardier beetles store hydroquinone and hydrogen peroxide in their abdomen. When they are threatened, they use the chemical to create an exothermic reaction and bring the mixture to its boiling point of water and eject it. The damage can be fatal.

4. Where is peroxide found?

Approximately all the eukaryotic cells form peroxide in peroxisomes. Peroxisomes are used for the catabolism and biosynthesis of compounds that are essential for health.

Peroxide is present in small amounts in plants, animals and the atmosphere as well.

In some animals, it is also a byproduct of any biochemical reaction.

5. What is Meant By the Peroxide Effect?

When any unsymmetrical reagent is treated with the unsymmetrical alkene in the presence of peroxide, then an addition occurs against Markownikoff's rule. It means the negative part of the reagent adds to that carbon-carbon double bond that carries more hydrogen atom count. This is called the peroxide effect.

6. What is Hydrogen Peroxide?

Hydrogen peroxide is defined as a chemical compound having the chemical formula H2O2. It is a colorless liquid in its pure form, which is slightly more viscous than water. However, for some safety reasons, it is commonly used as an aqueous solution. Hydrogen peroxide is given as the simplest peroxide, having the oxygen-oxygen single bond and finds use as a bleaching agent, disinfectant, and strong oxidizer. Simultaneously, concentrated 'high-test peroxide,' or hydrogen peroxide, is a reactive oxygen species that have been used as a rocket propellant.

7. What is Superoxide?

Superoxides are the compounds that contain the anion O2-. The electrical charge of these superoxide ions is -1. Only alkali metals are capable of forming superoxide compounds. NaO2 is an example of a superoxide compound.

8. Differentiate Between Peroxide and Superoxide?

Peroxide and superoxide are given as the oxides containing oxygen atoms. The primary difference between these both is: the oxidation state of oxygen in peroxide is -1; on the other side, the oxidation state of oxygen in superoxide is given as -1/2.