The binary nitrogen halides are thermodynamically unstable with respect to decomposition to the elements, with the exception of NF3.
NF3 has a much lower dipole moment than ammonia, and has no σ-donor properties. This is because F is more electronegative than N, and hence the N lone pair is polarized towards the F atoms (NF3 is Nδ+(Fδ-)3, whereas NH3 is Nδ-(Hδ+)3), and is therefore unavailable to act as an electron pair donor. It is inertto reaction with acids and alkalis, but does react with fluoride ion Lewis acid acceptors to produce a NV species:
NCl3: This is a volatile and explosive, and is hydrolyzed to give ammonia and hypochlorite ions.
NBr3 and NI3: these are very unstable and are not known free of ammonia.