Fluoro-nitrogen Cations.

The crystal structures of [NH F] [CF SO ] , [NH F ] [SbF ] , and [N F ] [Sb F ] 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 N F , N F , NF O , NH F , NH F , and NF . It is shown that the N-F bond length decreases from 1.40 Å to 1.26 Å 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.