A
structure with an unpaired electron
(but excluding certain metal ions). In organicmolecules, a radical is often associated with a
highly reactive
site of reduced valence
(see doublet).
The term radical is sometimes used to describe a substructure within a molecule; the term free
radical then describes a radical in this sense, viewed as the
result of cleaving the bond
linking the substructure to the rest of the molecule.
