Theoretical screening of bistriazole-derived energetic salts with high energetic properties and low sensitivity

We designed four series of energetic anions by replacing nitro group (NO₂) with trinitromethyl group (C(NO₂)₃) or by inserting N-bridging groups (-NH-, -NH-NH-, -N[double bond, length as m-dash]N-, -N[double bond, length as m-dash]N(O)-) into the bistriazole frameworks. The properties of 40 energetic salts, based on the bistriazole-derived anions and hydroxylammonium cation, were studied by density functional theory (DFT) and volume-based thermodynamics calculations (VBT). It is found that the newly designed energetic salts have good detonation properties due to their larger nitrogen content and better oxygen balance. And one of their corresponding hydroxylammonium salts exhibits better detonation performance (D = 10.06 km s^-1 and P = 48.58 GPa) than CL-20 (D = 9.54 km s^-1 and P = 43.36 GPa). Moreover, 10 energetic salts not only exhibit excellent energetic properties superior to CL-20, but also have lower sensitivity than CL-20 (h ₅₀ = 13.81 cm). In addition, we rationally selected salt B6 from the 10 salts to predict its crystal structure under pressures. By converting energetic molecules with excellent detonation properties into energetic ions, some highly bistriazole-derived energetic salts with both excellent performance and low sensitivity could be developed strategically.