Infrared Spectra and Structure of the Isomers of N2F2

The isomers of N2F2 have been characterized in the past by their reactivity towards mercury. Investigation of the infrared spectra showed that inactive N2F2 is trans-1,2-difluorodiazine and may be identified by the single strong band centered at 989 cm—1, with PQR structure. Active N2F2 resembles 1,1-difluorodiazine instead of a cis-isomer. This conclusion was reached by considering the mass spectrum, the chemical reactivity, and both the position of the infrared bands and their shapes. 1,1-difluorodiazine may be identified by strong bands at 1524 (PR), 952 (PQR), 896 (PR), and 737 (PQR) cm—1, respectively. Normal coordinate analyses using the Wilson FG-matrix method were performed on both isomers.