Calcium peroxide or calcium dioxide is the inorganic compound with the formula CaO₂. It is the

peroxide In chemistry, peroxides are a group of compounds with the structure , where R = any element. The group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable. The most common peroxide is hydrogen ...

(O₂²⁻) salt of Ca²⁺. Commercial samples can be yellowish, but the pure compound is white. It is almost insoluble in

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

Structure and stability

As a solid, it is relatively stable against decomposition. In contact with water however it hydrolyzes with release of oxygen. Upon treatment with an acid, it forms

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%� ...

Preparation

Calcium peroxide is produced by combining

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

salts and

: :Ca(OH)₂ + H₂O₂ → CaO₂ + 2 H₂O The octahydrate precipitates upon the reaction of calcium hydroxide with dilute

. Upon heating it dehydrates.

Applications

It is mainly used as an oxidant to enhance the extraction of precious metals from their ores. In its second main application, it is used as a food additive under the E number E930 it is used as

flour bleaching agent Flour bleaching agent is the agent added to fresh milled grains to whiten the flour by removing the yellow colour pigment called xanthophyll. It whitens the flour, which is used in the baking industry. Overview Usual flour bleaching agents are: * ...

and improving agent. In agriculture it is used in the presowing treatments of

rice seed Rice is the seed of the grass species ''Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera ''Zizania'' and '' Porteresia'', both wild and domesticated, ...

. Also, calcium peroxide has found use in aquaculture to oxygenate and disinfect water. In the ecological restoration industry it is used in the treatment of soils. Calcium peroxide is used in a similar manner to

magnesium peroxide Magnesium peroxide (MgO2) is an odorless fine powder peroxide with a white to off-white color. It is similar to calcium peroxide because magnesium peroxide also releases oxygen by breaking down at a controlled rate with water. Commercially, magne ...

for environmental restoration programs. It is used to restore soil and groundwater contaminated with petroleum by the process of enhanced in-situ

bioremediation Bioremediation broadly refers to any process wherein a biological system (typically bacteria, microalgae, fungi, and plants), living or dead, is employed for removing environmental pollutants from air, water, soil, flue gasses, industrial effluent ...

. It is a minor component of some dentifrices. It is also used for curing polythioether polymers by oxidising terminal thiol groups to disulphide bridges.

References

{{DEFAULTSORT:Calcium Peroxide Peroxides Calcium compounds Food additives Bleaches Disinfectants Oxidizing agents