Chemical Physics of Hydrazine Under Pressure

Hydrazine (N2H4) is a chemically versatile compound best known for its long-standing use as a high-performance rocket fuel. Its rich hydrogen-bonding network and reactive N–N bond make it an ideal system for investigating how pressure alters molecular interactions, structure, and thermodynamic stability. High pressure provides a unique thermodynamic pathway for accessing new phases and reactivity that are inaccessible under ambient conditions. By combining vibrational spectroscopy and synchrotron X-ray diffraction across a wide pressure range, this work establishes a unified picture of the structural, vibrational, and thermodynamic response of hydrazine to extreme compression. The results reveal multiple pressure-induced phase transitions, accompanied by systematic changes in vibrational modes and signatures of increased hydrogen bonding. An isothermal equation of state is determined from diffraction measurements and combined with spectroscopic data to model isotherms under compression, providing a framework for direct comparison between static high-pressure experiments and dynamic shock compression. In addition to pure hydrazine, this work explores the behavior of hydrazine in mixtures with other simple molecules, revealing distinct results that illuminate the thermodynamic drivers of reactivity in molecular systems. Together, these results deliver the most complete experimental characterization of hydrazine under extreme conditions to date. This work clarifies phase boundaries, constrains the high-pressure equation of state, and advances our fundamental understanding of pressure-induced phase transitions and reactivity in hydrogen-bonded molecular solids, with broader implications for planetary chemistry and the development of energetic materials.

Author dc:creator

• Roma Ripani (20766926)

• Chemistry, Physical
• Physics, Condensed Matter

Statement dc:rights

• In Copyright
• Open Access after 2028-05-01

DOI dc:identifier

https://doi.org/10.25417/uic.32994995.v1

OAI identifier oai:identifier

oai:figshare.com:article/32994995