Lithium peroxide is the

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

Li₂ O₂. Lithium peroxide is a white solid, and unlike most other alkali metal peroxides, it is nonhygroscopic. Because of its high oxygen:mass and oxygen:volume ratios, the solid has been used to remove CO₂ from and release O₂ to the atmosphere in

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

Preparation

It is prepared by the reaction of

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 viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

and

lithium hydroxide Lithium hydroxide is an inorganic compound with the formula LiOH. It can exist as anhydrous or hydrated, and both forms are white hygroscopic solids. They are soluble in water and slightly soluble in ethanol. Both are available commercially. While ...

. This reaction initially produces lithium

hydroperoxide Hydroperoxides or peroxols are Chemical compound, compounds of the form ROOH, where R stands for any group, typically Organic compound, organic, which contain the hydroperoxy functional group (). Hydroperoxide also refers to the hydroperoxide anio ...

:E. Dönges "Lithium and Sodium Peroxides" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 979. :LiOH + H₂O₂ → LiOOH + H₂O This lithium hydroperoxide may exist as lithium peroxide monoperoxohydrate trihydrate (Li₂O₂·H₂O₂·3H₂O). Dehydration of this material gives the anhydrous peroxide salt: :2 LiOOH → Li₂O₂ + H₂O₂ Li₂O₂ decomposes at about 450 °C to give

lithium oxide Lithium oxide (Lithium, Oxygen, O) or lithia is an Inorganic compound, inorganic chemical compound. It is a white or pale yellow solid. Although not specifically important, many materials are assessed on the basis of their Li2O content. For examp ...

: :2 Li₂O₂ → 2 Li₂O + O₂ The structure of solid Li₂O₂ has been determined by

X-ray crystallography X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract in specific directions. By measuring th ...

and

density functional theory Density functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body ...

. The solid features eclipsed "ethane-like" Li₆O₂ subunits with an O-O distance of around 1.5 Å.

Uses

Air Purification

It is used in

air purifiers An air purifier or air cleaner is a device which removes contaminants from the air in a room to improve indoor air quality. These devices are commonly marketed as being beneficial to allergy sufferers and asthmatics, and at reducing or eliminating ...

where weight is important, e.g.,

or other sealed spaces and apparatuses to absorb carbon dioxide and release oxygen in the reaction: Li₂O₂ + CO₂ → Li₂CO₃ + O₂ Similar to the reaction of lithium hydroxide with carbon dioxide to release 1 Li₂CO₃ and 1 H₂O, lithium peroxide has high absorption capacity and absorbs more CO₂ than does the same weight of lithium hydroxide and offers the bonus of releasing oxygen instead of water. Ulrich Wietelmann, Richard J. Bauer "Lithium and Lithium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH: Weinheim.

Polymerization of Styrene

Lithium peroxide can also act as a catalyst for polymerization of styrene to polystyrene. The polymerization of styrene to polystyrene typically involves the use of radical initiators via the free radical chain mechanism but lithium peroxide can also initiate radical polymerization reactions under certain conditions, although not as widely used.

Lithium-air Battery

The reversible lithium peroxide reaction is the basis for a prototype lithium–air battery. Using oxygen from the atmosphere allows the battery to eliminate storage of oxygen for its reaction, saving battery weight and size.

References

External links

WebElements entry
{{oxygen compounds Peroxides Lithium compounds Oxidizing agents