[en] Exposure of NF₄⁺AsF₆^- and NF₄⁺ SbF₆^- . 0.8SbF₅ to ⁶⁰Co γ rays at 77⁰K gave two paramagnetic centers, one of which is shown by ESR spectroscopy to contain one nitrogen atom and three equivalent fluorine atoms. Based on its magnetic properties it is identified as pyramidal NF₃⁺, a novel radical cation. The other center exhibits strong interaction of the electron with two fluorine atoms, weaker interaction with the antimony or arsenic central atom, and small interaction with several other fluorine atoms. It is tentatively assigned to the electron-loss species AsF₆, SbF₆, or Sb₂F₁₁ with the unpaired electron largely confined to two fluorine ligands. Irradiation of NF₄⁺BF₄^- did not result in well-defined magnetic centers. An improved synthesis of NF₄⁺BF₄^- is reported. (U.S.)