The reactions of the nitrogen oxides, N2O, NO, N2O3, NO2(N2O4), and N2O5, the oxychlorides ClNO and ClNO2, and the oxyanions NO2−and NO3−with the fluorosulfonating agents S2O6F2and BrOSO2F are studied systematically in regard to the formation of nitrosonium and nitronium fluorosulfate. Complex reactions are found when N2O3and N2O4are used as substrates, resulting in mixed or impure products. An explanation involving the intermediate oxidation into N2O5is put forward to explain the results.The solid products NOSO3F and NO2SO3F are characterized by powder X-ray analysis, infrared and Raman spectroscopy, and their solution behavior in HSO3F. Whereas NOSO3F has been found to have an orthorhombic lattice, NO2SO3F crystallizes in the monoclinic system. Unit cell parameters are reported. The vibrational spectra are interpreted in terms of ionic compounds NO+SO3F−and NO2+ − SO3F−. The SO3F−anion, however, appears to be perturbed and all theEmodes are slightly split. No unambiguous evidence for a previously reported non-linear NO2+cation is found. Force constants for this species are calculated assumingD∞hsymmetry.Both compounds are found to be completely dissociated in HSO3F as evidenced by conductometry and1H and19F nuclear magnetic resonance (n.m.r.) spectroscopy.