Abstract
The total splitting of the ESR proton hyperfine spectra of the cyclic π‐electron radicals, CnHn, is investigated. Theoretical expressions for the total splitting are derived in terms of the parameters of the Colpa—Bolton (CB) and Giacometti—Nordio—Pavan (GNP) extensions of McConnell's relationship. The application of these equations to the experimental results for radicals CnHn is discussed. The application of the CB and GNP correlations to the calculation of the proton splittings for alkyl‐substituted CnHn radicals is also discussed.