oxydant

An oxydant, or oxidant, is a chemical species that accepts electrons from another substance in a redox reaction. By doing so, the oxydant is reduced and the donor substance is oxidized. Oxidants are typically described by their redox potentials; strong oxidants have large positive potentials and can drive difficult oxidations.

Common oxidants include molecular oxygen (O2), hydrogen peroxide (H2O2), ozone (O3), halogens such as chlorine (Cl2) and bromine (Br2), permanganate (MnO4-) and dichromate (Cr2O7^2-) in acidic media, as well as nitrate and perchlorate species. In biology, reactive oxygen species such as superoxide and hydrogen peroxide act as controlled oxidants in signaling pathways, but can cause damage at high levels.

Applications of oxidants span chemical synthesis, bleaching and disinfection, and polymer processing. The term oxidant is synonymous with oxidizing agent in English usage; strength and mechanism are often described by standard redox potentials and reaction conditions.

Safety and handling depend on the specific substance, as many oxidants are reactive, corrosive, or toxic. Proper storage, concentration control, and protective equipment are essential in their use.