Single Crystal X-Ray Diffraction and Raman Spectroscopy of Hydrazine at High Pressures

Synchrotron single crystal x-ray diffraction and Raman spectroscopy have been used to investigate the structure and vibrational properties of hydrazine up to 52 GPa. Diffraction data from ambient pressure to 37 GPa reveal a phase transition in hydrazine from the P2 1 /m (Z = 2) phase to a phase with P-1 symmetry (Z = 4) at approximately 20 GPa. The structure of the high pressure phase was solved by direct methods. Raman measurements up to 52 GPa in the range of 3000 cm -1 to 3500 cm -1 show splitting in both the symmetric and asymmetric N-H stretching vibration bands near the transition pressure, indicating a change in hydrogen bonding at the transition pressure, consistent with the diffraction data. These results resolve several inconsistencies in the literature and provide useful baseline information on this important energetic material.

This work was supported by DOE/NNSA through the Chicago/DOE Alliance Center and by the DoD/ARO through the EXtreme EnErgy Density Center at the University of Illinois Chicago.