Theoretical research about nonmetallic energetic salts with pentazolate anion

Significant progress has been made in the synthesis of nitrogen-rich high-energy salts by pairing pentazolate anion (cyclo-N₅^-) with different cations since cyclo-N₅^- was synthesized. It is difficult to screen out cyclo-N₅^- salts with high energy quickly and effectively in experiment, while theoretical research can realize this goal. Herein, nineteen high-energy salts, which were composed of tetrazole cation and cyclo-N₅^- anion, were designed. And their properties were studied via density functional theory and volume-based thermodynamic methods. The results indicate that most salts have high densities, low sensitivities, and good detonation properties. In particular, salt 14 (ρ_Calib = 1.802 g/cm³, ΔH_f = 1058.4 kJ/mol, D = 9.38 km/s, P = 39.10 GPa, h₅₀ = 44.92 cm) exhibits excellent detonation performance (approximating that of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20)) superior to 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and lower impact sensitivity than CL-20 or HMX. Hence salt 14 is regarded as promising candidates for high-performance energetic materials.