Several scenarios are considered for the effect of electrolytes, specifical
ly for ion pairing, on the rates of electron transfer reactions: (i) electr
on transfer followed by ion transfer, (ii) ion-pair dissociation followed b
y electron transfer, or (iii) ion transfer accompanying the electron transf
er. The latter may involve fast or slow (diffusive) ionic motion. A distinc
tion is made between ion reorganization (case (iii)) and the formation of r
eal chemical intermediates. The ion pairs themselves may be tight (contact)
or loose (solvent separated). The discussion is illustrated with an exampl
e in the literature. Differences in degree in behavior of intramolecular an
d intermolecular electron transfer, due to differences in extent of ionic m
otion, are noted.