Fluoro-nitrogen Cations

The crystal structures of [NH3F](+)[CF3SO3](-), [NH2F2](+)[SbF6](-), and [N2F3](+)[Sb3F16](-) have been determined, representing the first structural characterizations of these simple fluoro-nitrogen cations. The influences of the hybridization of the central nitrogen atom and of the number of fluorine substituents on the N-F bond lengths are evaluated for the series N2F+, N2F3+, NF2O+, NH3F+, NH2F2+, and NF4+. It is shown that the N-F bond length decreases from 1.40 angstrom to 1.26 angstrom with increasing fluorine substitution and increasing s-character of the nitrogen atom, and that unusual N-F bond lengths reported in the previous literature are caused by disorder problems