persistent

https://doi.org/10.1351/goldbook.P04516
A term used to characterize
radicals
which have lifetimes of several minutes or greater in
dilute solution
in
inert
solvents. Persistence is a kinetic or reactivity property. In contrast, radical
stability
, which is a thermodynamic property, is expressed in terms of the C–H bond strength of the appropriate hydrocarbon. The
lifetime
of a radical is profoundly influenced by steric
shielding
of the radical centre by bulky substituents.
See also:
transient
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1150 [Terms] [Paper]