Transformation of hydrazinium azide to molecular N-8 at 40 GPa

摘要

Hydrazinium azide (HA) has been investigated at high pressures to 68 GPa using confocal microRaman spectroscopy and synchrotron powder x-ray diffraction. The results show that HA undergoes structural phase transitions from solid HA-I to HA-II at 13 GPa, associated with the strengthening of hydrogen bonding, and then to N-8 at 40 GPa. The transformation of HA to recently predicted N-8 (N equivalent to N+-N-N=N-N--(+) N equivalent to N) is evident by the emergence of new peaks at 2384 cm(-1), 1665 cm(-1), and 1165 cm(-1), arising from the terminal N equivalent to N stretching, the central N=N stretching, and the N N stretching, respectively. However, upon decompression, N-8 decomposes to epsilon-N-2 below 25 GPa, but the remnant can be seen as low as 3 GPa. Published by AIP Publishing.