A free radical is an atom or group of atoms containing an unpaired electron. A free-radical reaction then is any chemical reaction in which a species with an unpaired electron is involved at some ...A free radical is an atom or group of atoms containing an unpaired electron. A free-radical reaction then is any chemical reaction in which a species with an unpaired electron is involved at some stage along the reaction pathway. Although a free radical conceivably can be a starting material or a product in a reaction, in practice, free radicals are reaction intermediates in nearly every instance.
