An Fe(II) ion at an α-cation exchange position of ferrierite, (Fe)α, was taken as a model for the active site in nitrous oxide decomposition and in the selective oxidation of phenol with nitrous oxide. The oxygen that is deposited via the decomposition of N2O is commonly referred to as α-oxygen, (O)α. Comparison with the results of cluster model calculations was performed for reaction of benzene-to-phenol oxidation. Periodic calculations predict the same reaction path for benzene oxidation as does the cluster model study. Differences in the adsorption modes for both types of calculations were analyzed and discussed.