Definition of free radical in English:

free radical


  • An uncharged molecule (typically highly reactive and short-lived) having an unpaired valency electron.

    and → free
    • ‘This free radical attacks the double bonds on other monomers creating a longer chain molecule and an additional free radical.’
    • ‘It is produced through a free radical polymerization reaction of styrene monomers.’
    • ‘In the free radical polymerization of ethylene to form polyethylene, a small amount of a peroxide is added to a large volume of ethylene.’
    • ‘These free radicals are highly reactive chemically and can themselves alter molecules in the cell.’
    • ‘It is well known that high-temperature free radical reactions can be quenched by the presence of nitric oxide, itself a free radical.’


free radical