peroxide

Peroxide refers to a class of chemical compounds that contain an oxygen–oxygen single bond, the peroxy linkage. The term covers inorganic peroxides such as sodium peroxide (Na2O2) and barium peroxide (BaO2), as well as organic peroxides and hydroperoxides (for example hydrogen peroxide, H2O2, and hydroperoxides ROOH or diacyl peroxides). Peroxides are typically strong oxidizing agents and show varied physical forms, from colorless liquids to solids, depending on their substituents. They are often thermally unstable and decompose exothermically, releasing water and oxygen or other oxidized products. Decomposition can be catalyzed by heat, light, trace metals, or impurities, requiring careful handling and storage.

Hydrogen peroxide is the most widely encountered peroxide and is produced commercially by the anthraquinone process. Inorganic peroxides are usually prepared by direct reaction of oxygen with metals or metal oxides, and some are used as oxidants, bleaching agents, or initiators. In nature, peroxides form transiently in the atmosphere through photochemical reactions and are found in trace amounts in certain minerals and biological systems.

Applications of peroxides are diverse. Hydrogen peroxide is used as a disinfectant, antiseptic, and bleaching agent in textiles, paper, and cosmetics, and as a mild oxidant in chemical synthesis. Organic peroxides serve as radical initiators in polymerization and curing reactions, while inorganic peroxides find uses in bleaching, oxidation, and propulsion contexts. Safety concerns arise from their strong oxidizing properties: they can pose fire and explosion hazards, especially when concentrated or in contact with reducing agents, metals, or organics. Proper storage in cool, dark, well-ventilated conditions and appropriate containment is essential.