High-pressure structural studies of energetic materials

This article reviews how the advances in the techniques for the collection and analysis of high-pressure X-ray and neutron diffraction data, augmented by spectroscopic data, now permit the accurate determination of the full crystal structure of energetic materials under extreme conditions. Using these methods, the crystal structure of the high-pressure gamma-form of RDX (1,3,5-trinitrohexahydro-striazine) has been determined - the first case of a high-pressure structure of an energetic material. In addition, the crystal structure of the highly metastable beta-form has been determined and, contrary to the previous reports, has been shown to be different from the form obtained at elevated temperatures and pressures

The crystal structure of beta-RDX-an elusive form of an explosive revealed

The crystal structure of the highly metastable β-form of RDX shows that the molecules adopt different conformations compared to the α-form and that, contrary to previous reports, the β-form obtained at ambient pressure is not the same form as that obtained at elevated temperatures and pressures

Pressure-cooking of explosives-the crystal structure of epsilon-RDX as determined by X-ray and neutron diffraction

The high-pressure, high-temperature epsilon-form of the widely used explosive RDX has been structurally characterised using a combination of diffraction techniques, and a sample of this form has been successfully recovered to ambient pressure

High-pressure structural studies of energetic compounds

The phase diagram of the energetic material hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been explored using X-ray and neutron diffraction from ambient pressure to 8GPa. Two phases of RDX have been structurally characterized. The high-pressure -polymorph exists above 4GPa while the metastable -polymorph has been isolated from the high boiling point solvent nitrobenzene. Interestingly, neutron diffraction measurements at high pressures and high temperatures show that the -polymorph isolated under ambient conditions is not the same polymorph as can be accessed at high pressures and temperatures