Abstract:
Infrared and Raman spectra of N2H6SO4 have been investigated through the phase transitions at 230 K (III-II) and 483 K (II-I) and assignments made to the various vibrational modes. The assignments have been confirmed by studies of the deuterated compound. The internal modes of both N2H62+ and SO42− ions show marked changes across the phase transitions. The torsional mode of N2H62+ with a fundamental frequency of 517 cm−1 in the room-temperature phase II, disappears in the high-temperature phase, I, accompanied by the appearance of the vq bending mode at 845 cm−1. The torsional barrier is estimated to be ≈32 kJ mol−1. The hydrazonium ion in the high-temperature phase is comparable to ethane. The SO42− ion bands also show marked changes across the phase transitions, the v1 and v2 bands disappearing in the high-temperature phase. In the low-temperature phase, III, both molecular ions are more distorted than in the room-temperature phase.
