Extensive theoretical studies on two new members of the FOX-7 family: 5-(dinitromethylene)-1,4- Dinitramino-tetrazole and 1,1 0 -dinitro-4,4 0 -diamino- 5,5 0 -bitetrazole as energetic compounds

Two novel compounds 5-(dinitromethylene)-1,4-dinitramino-tetrazole (DNAT) and 1,1 -dinitro-4,4- diamino-5,5 -bitetrazole (DNABT) were suggested to be potential candidates of high energy density materials (HEDMs). The optimized geometry, NBO charges and electronic density, HOMO-LUMO, electrostatic potential on the surface of molecules, the IR spectrum and thermochemical parameters were calculated for inspecting the electronic structure properties at B3LYP/6-311++G∗level of theory. Meanwhile, the solid states of DNAT and DNABT were studied using the crystal packing models by the plane-wave periodic local-density approximation density functional theory. Four stable polymorphous cells have been found including P2₁2₁2₁, P2₁/c, P &macr1 and Pbca, assigned to the orthorhombic, monoclinic and triclinic lattice systems. In addition, properties such as density, enthalpy of formation and detonation performance have also been predicted. As a result, the detonation velocity and pressure of two compounds are found to be very remarkable (DNAT: D = 9.17 km s^-1, P = 39.23 GPa; DNABT: D = 9.53 km s^-1, P = 40.92 GPa). Considering the tetrazole rings with energetic groups and the insensitive fragment of FOX-7, high positive heat of formation (583.50 kJ mol^-1 and 1081.39 kJ mol^-1) and eminent performance render DNAT and DNABT to be very promising powerful energetically insensitive compounds. This work provides theoretical support for further experimental synthesis.This