Chrysene (1), 6-fluorochrysene (2), 6-chlorochrysene (3), and 6-bromochrysene (4) are cleanly monoprotonated in FSO 3 H‚SbF 5 (ca. 10:1)/SO 2 ClF at the C-12 position. 6-Acetylchrysene (5) is CO-protonated in FSO 3 H/SO 2 ClF with significant charge delocalization into the chrysene and provides a model for a C-6-protonated chrysenium cation. 4H-Cyclopenta[def]chrysene (6) is protonated at C-5 (site of bromination and acetylation). The observed chrysenium (methanochrysenium) cations are those predicted by AM1 to have the lowest energies. The NMR characteristics of the resulting arenium ions are discussed and the ∆δ 13 Cs are compared with AM1 calculated changes in charges [∆q c ) q c (ion) -q c (neutral)]. Possible relationships between the charge delocalization path in chrysenium ions and metabolic activation of chrysenes by electrophilic pathways via the bay-region epoxide ring opening (f PAH-DNA adduct) are evaluated.