Difference Between Peroxide and Dioxide

Peroxide vs Dioxide

Oxygen is a very common element that participates in oxidation reactions with many other elements. Therefore, there are large numbers of oxygen containing compounds in the nature. All these compounds contain oxygen atoms in different oxidation states. Because of that, there chemical reactivity and chemical bonding patterns are different from each other. Peroxide and dioxide are such oxygen containing molecules.


Peroxide is an oxygen containing anion with the molecular formula of O22-. Two oxygen atoms are bonded by a covalent bond, and each oxygen atom has the oxidation number of -1. Peroxide anion can usually join with other cations like H+, other group 1 or group 2 cations, or transition metals to form peroxide compounds. Further, they can be a part of the organic compounds. Hydrogen peroxide is the simplest form of peroxide, which is denoted as H2O2. The oxygen-oxygen single bond in the peroxide is not that stable. Therefore, it can easily undergo hemolytic cleavage producing two radicals. Hence, peroxides are very reactive and don’t occur much in the nature.

Peroxide is a strong nucleophile and an oxidizing agent. Since, they are easily subjected to chemical reactions when they expose to light or heat, they are stored in cool, dark containers. Peroxides react with skin, cotton and many other materials easily, so have to handle with care. Peroxides are produced as a by-product of various chemical reactions or as an intermediate. This type of reactions happens inside our bodies too. Peroxide has toxic effects inside our cells. Therefore, they have to be neutralized as soon as they are produced. Our cells have a special mechanism for that. There is an organelle called peroxisomes in our cells, which contain the catalase enzyme. This enzyme catalyses the decomposition of hydrogen peroxide into water, and oxygen, thus do a detoxification function. Hydrogen peroxide has hazardous properties, like decomposition to oxygen and water with evolution of heat, or decomposes due to contamination or contact with active surfaces, due to the formation of oxygen pressure increases inside the containers and it also can form explosive mixtures. Bleaching action of hydrogen peroxide is due to oxidation and release of oxygen. This oxygen will react with coloring matter to make it colorless.

H2O2       H2O    + O

O + Coloring Matter    →     Colorless Matter

Peroxides are used for bleaching. So peroxides are widely used for hair or skin bleaching in salons, clean bathrooms, and to remove stains from clothes.


Dioxide is the term used when a molecule has two oxygen atoms. Though we can say hydrogen peroxide is a dioxide, according to this definition, there are some differences. When we say dioxide, we normally think of a compound containing oxygen atoms and have the following characteristics. In a dioxide, two oxygen atoms are separately bonded with the other atom in the molecule. For example, in the case of carbon dioxide, two oxygen atoms are bonded with carbon separately. Each oxygen forms a double bond with carbon; therefore, is in the -2 oxidation state. Likewise, sulfur dioxide, nitrogen dioxide, titanium dioxide are other compounds where there are two oxygen atoms with a -2 oxidation state.


What is the difference between Peroxide and Dioxide?

• In peroxide, two oxygen atoms are bound together. In dioxide, oxygen atoms are not bound together, rather they are bound separately with another atom.

• Peroxide can be taken as a separate, charged ion with a -2 charge, but dioxide is not taken as a separate ion. It’s a part of a molecule.

• In peroxide, oxygen has the oxidation number of -1, whereas, in a dioxide oxygen has the oxidation number of -2.