Putting the squeeze on energetic co-crystals: High-pressure studies of 2(CL-20):HMX and CL-20:TNT

摘要

Two energetic co-crystal systems - 2(CL-20):HMX, and CL-20:TNT- have been investigated under pressure using neutron powder diffraction on the PEARL beamline at the ISIS Neutron Source in Harwell, Oxfordshire; and the results compared in this paper. As reported in last year's conference, 2(CL-20):HMX was prepared with a ResoDyn LabRAM Resonant Acoustic Mixer using a published method. Smooth compression was observed in this system up to 3.5 GPa, and equations of state were determined, with no observed phase transitions in this pressure range. The bulk modulus of this co-crystal was determined to be intermediate to that of its co-formers. Conversely - anisotropic compression was observed in CL-20:TNT, with a potential phase transition occurring at 4.1 GPa. Structures were refined for each pressure point, and used to derive an equation of state up to 3.6 GPa. In this case, however, the bulk modulus for CL-20:TNT was found to be greater than that of its co-formers.