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High-pressure structural evolution and intermolecular interactions in CL-20 and the CL-20/HMX cocrystal
Junyu Fan1,2, Xiaoxuan Han1,2, Xiaoran Shi1,2
1Department of Physics, Taiyuan Normal University, Jinzhong, 030619, China.
Physical Chemistry Chemical Physics : PCCP
|September 26, 2025
Summary
High-pressure Raman spectroscopy reveals pure CL-20 transforms above 2 GPa due to nitro group reorientation. However, CL-20/HMX cocrystals remain stable up to 15 GPa, aided by hydrogen bonding and vibrational coupling.
Area of Science:
- Materials Science
- Chemistry
- Physics
Background:
- Understanding energetic materials (EMs) under pressure is vital for safety and performance.
- High-pressure behavior influences sensitivity and stability.
Purpose of the Study:
- To investigate the high-pressure structural stability of CL-20 and CL-20/HMX using Raman spectroscopy.
- To elucidate pressure-induced structural transformations and intermolecular interactions.
Main Methods:
- Pressure-dependent Raman spectroscopy.
- Analysis of structure responses and intermolecular interactions.
- High-pressure studies up to 15 GPa.
Main Results:
- Pure CL-20 undergoes a phase transformation between 2-6 GPa, with altered nitro group orientation.
- CL-20/HMX cocrystal maintains structural stability up to 15 GPa.
- Hydrogen bonding and vibrational mode coupling enhance CL-20/HMX stability.
Conclusions:
- CL-20 exhibits significant pressure-induced structural changes.
- CL-20/HMX demonstrates remarkable structural integrity under high pressure.
- Spectroscopic signatures reveal mechanisms of enhanced stability in cocrystals.
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