Intermolecular interactions, thermodynamic properties, crystal structure, and detonation performance of HMX/NTO cocrystal explosive

Density functional theory calculation was performed to investigate the intermolecular interactions, thermodynamic properties, crystal structure, and detonation performance of CL-20 (2,4,6,8,10,12-hexanitrohexaazaisowurtzitane)/TEX (4,10-dinitro- 2,6,8,12-tetraoxa-4,10-diaza-tetracyclododecane) cocrystal explosive. The results of natural bond orbital (NBO) and atoms in molecules analysis show that unconventional CH···O type hydrogen bonds and dispersion force are the main driving forces for the cocrystal formation. Monte Carlo simulation was employed to predict the crystal structure of the CL-20/TEX cocrystal. The cocrystal is most likely to crystallize in a monoclinic system (space group C2/C), with cell parameters a = 40.62 A, b = 7.35 A, c = 41.36 A, and = 157.38°. Based on crystal density, chemical energy, and heat of formations, detonation performance was calculated using Kamlet-Jacobs formulas. Detonation velocity and pressure of the CL-20/TEX cocrystal are higher than those of TEX but a litter lower than those of CL-20. Bond dissociation energy analysis shows that the cocrystal is thermal stable and meets the requirement of high energy density materials.