Transformation of hydrazinium azide to molecular N8 at 40 GPa

Sakun Duwal; Young-Jay Ryu; Minseob Kim; Choong-Shik Yoo; Sora Bang; Kyungtae Kim; Nam Hwi Hur

doi:10.1063/1.5021976

Transformation of hydrazinium azide to molecular N₈ at 40 GPa

J Chem Phys. 2018 Apr 7;148(13):134310. doi: 10.1063/1.5021976.

Authors

Sakun Duwal¹, Young-Jay Ryu¹, Minseob Kim¹, Choong-Shik Yoo¹, Sora Bang², Kyungtae Kim², Nam Hwi Hur²

Affiliations

¹ Department of Chemistry and Institute for Shock Physics, Washington State University, Pullman, Washington 99164, USA.
² Department of Chemistry, Sogang University, Seoul 121-742, South Korea.

PMID: 29626901
DOI: 10.1063/1.5021976

Abstract

Hydrazinium azide (HA) has been investigated at high pressures to 68 GPa using confocal micro-Raman 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 N₈ at 40 GPa. The transformation of HA to recently predicted N₈ (N≡N⁺-N^--N=N-^-N-⁺N≡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≡N stretching, the central N=N stretching, and the N-N stretching, respectively. However, upon decompression, N₈ decomposes to ε-N₂ below 25 GPa, but the remnant can be seen as low as 3 GPa.