A series of bridged 2,2-bi(1,3,4-oxadiazole) energetic derivatives were designed and their geometrical structures, electronic structures, heats of formation, detonation properties, thermal stabilities and thermodynamic properties were fully investigated by density functional theory. The results showed that the –N₃ group and the –N– bridge play an important role in improving heats of formation of these 2,2-bi(1,3,4-oxadiazole) derivatives. The calculated detonation properties indicated that the –NF₂ group and the –N– bridge were very useful for enhancing the heats of detonation, detonation velocities and detonation pressures. Twenty-four compounds were found to possess equal or higher detonation properties than those of RDX, while 14 compounds had equal or higher detonation properties than those of HMX. The analysis of the bond-dissociation energies suggested that the –CN group was the effective structural unit for increasing the thermal stabilities while the –NHNH₂ group decreased these values. Overall, taking both the detonation properties and thermal stabilities into consideration, 22 compounds (A4, A6, A8, A9, B4, B9, C2, C3, C4, C5, C7, C, C9 D4, D8, D9, E9, F4, F9, G9, H4 and H9) were selected as the potential candidates for high-energy-density materials.

In the present study, 64 energetic compounds based on 1,2,5-oxadiazole were designed and their energy gaps, heats of formation (HoF), detonation properties, and thermal stabilities were fully investigated by density functional theory at the B3LYP/6-311G(d,p) level. All the designed compounds possessed high positive ΔH_f,gas values and the –NH– bridge and –N₃ group were the most effective ones for improving the HoFs of these compounds. The predicted densities and detonation properties showed that –C(NO₂)₃ and –O– were the most effective groups to improve the densities, while –C(NO₂)₃ and –NH– were the most effective groups to improve the detonation velocities. When the compounds were substituted by –NHNH₂/–NHNO₂/–C(NO₂)₃/–CH(NO₂)₂ groups, the BDE values of the NH–NH₂/NH–NO₂/C–(NO₂)₃/CH–(NO₂)₂ bonds were the lowest, which indicated that the NH–NH₂/NH–NO₂/C–(NO₂)₃/CH–(NO₂)₂ bond cleavages were the possible thermal decomposition path for these compounds. In addition, incorporating the –NHNH– bridge into the compounds decreased the BDE values. Overall, the effects of the substituents on these properties were combined with those of the bridge groups. Taking the detonation properties and thermal stabilities into consideration, eight compounds (A3, C2, C3, C6, D3, G3, H3, and H5) were selected as high-energy-density compounds and their electronic structures were investigated to gain a better understanding of these compounds.

Density functional theory was employed to investigate ten 1,2,4,5‐tetrahydro‐1,2,4,5‐tetrazine‐based energetic materials. The heats of formation and detonation properties were calculated by isodesmic reactions and Kamlet–Jacobs equations. The thermal stabilities and impact sensitivities were also estimated to give a better understanding of their decomposition mechanism. The results indicate that all of the designed compounds have high positive heats of formation ranging from 525.1 to 1639.1 kJ mol⁻¹, moderate detonation properties (heats of detonation of 536.6 to 2187.6 cal g⁻¹, theoretical densities of 1.48 to 2.32 g cm⁻³, detonation velocities of 7.02 to 12.18 km s⁻¹, and detonation pressures of 19.8 to 75.1 GPa), and acceptable stabilities (bond dissociation energies of 0.8 to 104.9 kJ mol⁻¹). Taking both the detonation properties and the stabilities into consideration, compounds A4 and B4 were finally selected as promising candidates of high‐energy‐density materials, as their detonation properties and impact sensitivities were superior to those of HMX. Additionally, the frontier molecular orbitals, electronic densities, electrostatic potentials, and thermal dynamic parameters of compounds A4 and B4 were also investigated.