radical centre(s)

The atom (or group of atoms) in a polyatomic radical on which an unpaired electron is largely localized. @A00512@ of a monovalent atom to a radical centre gives a molecule for which it is possible to write a @L03513@ in which the normal @S05900@ valencies are assigned to all atoms.
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1156 [Terms] [Paper]