Compression of Hydrazine to above 200 GPa.

Hydrazine (N₂H₄) was subjected to pressures up to 213 GPa and analyzed using synchrotron infrared spectroscopy, X-ray diffraction, and Raman spectroscopy. These measurements reveal several phase transitions accompanied by changes in hydrogen bonding, with indications of potential partial symmetrization of hydrogen bonds at elevated pressures. The findings are compared to theoretical predictions of structure, phase transitions, and equations of states of N₂H₄ as well as the behavior of H₂O and NH₃ at these pressures. We also examined the pressure-induced chemistry of hydrazine with other molecules. The implications for the Hugoniot of hydrazine are discussed.