Radical (Atomic)

A radical is an uncharged atom or molecule that has an unpaired, or "free," electron. Radicals are formed when a covalent bond in an atom or molecule is split apart and the remaining pieces retain one electron of the original shared pair. These reaction products, called free radicals, are highly reactive entities that can participate in a variety of reactions. In chemical notation, radicals are indicated by the chemical symbol of the parent compound followed by a dot .

Free radicals can be quenched by antioxidants, chemicals that are capable of absorbing their extra electron. Antioxidants are free radical scavengers that can dampen the propagation reactions which create further radicals. They are important dietary supplement and find some use in topical skin care applications. Many of these radical scavengers, like vitamin E from green tea and polyphenols from red wine, are naturally occurring compounds.