The role of the atomic oxygen form (alpha-form) produced upon N2O decomposition on Fe-containing ZSM-5 in the conversion of adsorbed benzene molecules was studied with the ESR technique. alpha-Oxygen was shown not to participate in the formation of electron acceptor sites (A(s)) responsible for ionization of aromatic compounds. The ionization process proceeded in both the presence and absence of the alpha-form. But in the latter case, instead of benzene cation radicals, ESR spectra revealed those of phenol resulting from benzene oxidation by alpha-oxygen.