Preparation and properties of perfluoroammonium tetrafluoroborate, NF4+BF4-, and possible synthesis of nitrogen pentafluoride

Article abstract of DOI:10.1021/ic50113a051

A new crystalline compound, NF₄⁺BF₄^-, has been prepared by exposing the heterogeneous ternary system NF₃-BF₃-F₂ to 3-MeV bremsstrahlung at 77°K. The G value for the reaction (molecules isolated per 100 eV absorbed) is about unity. The compound is stable at room temperature in dry air; it decomposes above 250° to the reactants. It reacts rapidly with moisture and with organic substances. The indicated ionic structure is confirmed by infrared and Raman spectroscopy. The X-ray powder pattern can be indexed on the basis of a tetragonal unit cell with a = 7.01 and c = 5.22 A?. Irradiation of mixtures of nitrogen trifluoride and excess fluorine at 77°K has led to isolation in low yields of a white solid. It decomposes below 143°K to liberate nitrogen trifluoride and reacts with boron trifluoride at low temperature to form NF₄BF₄. Its most likely identity is perfluoroammonium fluoride.