Theoretical studies of azide-azole nitrogen-rich energetic compounds

Based on the crystal data of 2-azido-1, 3-imidazole, 3-azido-1, 2, 4-triazole and 5-azido-1H-tetrazole, a novel of azido-pentazole was firstly devised. The most stable molecular geometries of azide-azole compounds were obtained using B3LYP methods with 6-311++G^** basis set. Compared with existing experimental data, B3LYP/6-311++G^** is the suitable basis set for compounds. Moreover, IR spectra and bond order of azide-azole nitrogen-rich energetic compounds were obtained. The results show that they have not imaginary frequencies, so they were stable on the potential energy surface. There is a great conjugate system among molecular structures. The frontier orbital energies and their differences predict that the stabilities of the title compounds decrease in the order: 5-azido-1H-tetrazole > 3-azide-1, 2, 4-triazole > azido-pentazole > 2-azido-1, 3-imidazole. The results show that heat of formation, density, detonation velocity and detonation pressure of the title compounds linearly increase with increasing nitrogen mass fraction in the system. Azido-pentazole with detonation velocity of 9897 m • s^-1, and the detonation pressure of 46.0 GPa, which has potential applications in the high energy density materials.