Structure and detonation performance of a novel HMX/LLM‐105 cocrystal explosive

Intermolecular interactions and properties of octahydro-1,3,5,7-tetranitro-1,3,5,7- tetrazocine (HMX) / 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) cocrystal were studied by using the dispersion-corrected density functionals (ωB97XD, B97D) and meta-hybrid functional (M062x) methods. Binding energies, heats of formation, thermodynamic properties, atoms in molecules, and natural bond orbital analysis were performed to investigate HMX/LLM-105 complexes. Results show that the main intermolecular interactions between HMX and LLM-105 are CH…O, NH…O, N…O, and O…O interactions. In addition, Monte Carlo simulation was employed to predict the crystal structure of HMX/LLM-105 cocrystal. The HMX/LLM-105 cocrystal is most likely to crystallize in C2/c space group, and its corresponding cell parameters are Z = 8, a = 41.63 A, b = 6.77 A, c = 45.63 A, s = 164.55°, and ρ = 1.99 g/cm3. Detonation velocity and pressure of HMX/LLM-105 cocrystal are 8.95 km/s, 37.69GPa, a little lower than those of HMX (9.10 km/s, 37.76GPa). However, according to the net charges of nitro group, HMX/LLM-105 cocrystal exhibits less sensitive than HMX. Finally, bond dissociation energy calculation shows that HMX/LLM-105 complexes are thermally stable. Considering thermal stability, sensitivity, and detonation performance, HMX/LLM-105 cocrystal meets the requirements of insensitive high energy density materials. Copyright © 2013 John Wiley & Sons, Ltd.