Peroxide

In chemistry, peroxides are a group of compounds with the structure R−O−O−R, where R is any element.^[1][2] The O−O group in a peroxide is called the peroxide group or peroxy group (sometimes called peroxo group or peroxyl group). The nomenclature is somewhat variable,^[3] and the term was introduced by Thomas Thomson in 1804 for an oxide with the greatest quantity of oxygen.^[4]

Types of peroxides, from top to bottom: peroxide ion, organic peroxide, organic hydroperoxide, peracid. The peroxide group is marked in blue. R, R¹ and R² mark hydrocarbon moieties.

For other uses, see Peroxide (disambiguation).

The most common peroxide is hydrogen peroxide (H₂O₂), colloquially known simply as "peroxide". It is marketed as solutions in water at various concentrations. Many organic peroxides are known as well.

Structure and dimensions of H₂O₂ in gas phase.

In addition to hydrogen peroxide, some other major classes of peroxides are:

• Peroxy acids, the peroxy derivatives of many familiar acids, examples being peroxymonosulfuric acid and peracetic acid, and their salts, one example of which is potassium peroxydisulfate.
• Main group peroxides, compounds with the linkage E−O−O−E (E = main group element).
• Metal peroxides, examples being barium peroxide (BaO₂), sodium peroxide (Na₂O₂) and zinc peroxide (ZnO₂).
• Organic peroxides, compounds with the linkage C−O−O−C or C−O−O−H. One example is tert-butylhydroperoxide.

References

1. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
2. Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, ISBN 978-0-471-72091-1
3. IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "peroxides". doi:10.1351/goldbook.P04510
4. Harper, Douglas. "peroxide". Online Etymology Dictionary.