Effect of Vacancy Defects on Thermal Decomposition Mechanism of NTO Crystals

A perfect crystal model containing 256 3-nitro-1, 2, 4-triazol-5-one (NTO) molecules and defects crystal models containing 0.78%, 1.17%, 2.34%, 3.13% and 5.10% vacancy content, respectively, were constructed to study the effect of vacancy defects on the thermal decomposition of NTO. The potential energy and products of the six models at 1500 K were calculated, respectively. The initial reaction paths and decomposition rates were analyzed. The results show that at 1500 K, there are four paths for the initial decomposition of NTO:NTO aggregates to produce clusters, C-NO2 bond breaks to remove nitro, intermolecular proton transfer to cause ring opening and breaking (including C3-N4, N1-C5 bond fracture and C3-N4, N1-N2 bond fracture). In the range of 0.78%-2.34% vacancy content, with the increase of defect content, the frequency of the four initial reactions increases, the protonation reaction advances, and the ring fracture reaction delays. When the defect content exceeds 2.34%, the existence of vacancy leads to crystal collapse, the frequency of four initial reactions decreases, and the frequency of complex reactions increases. The existence of vacancy defects accelerates the overall thermal decomposition process. The above research results can be used to guide the regulation of NTO thermal safety.