How Energetic are cyclo‐Pentazolates?

Abstract

AbstractThe enthalpies of formation of the cyclo‐pentazolates and azides of N2H5+, NH3OH+, NH4+, C(NH2)3+, and N(CH3)4+ were calculated with the G3MP2 method and together with the experimental densities used to predict with the Cheetah program the performances of these salts as explosives and propellants. As explosives, the cyclo‐N5− (c‐N5−) salts outperform the corresponding azides by a significant amount but as rocket propellants, their performance is slightly inferior. Although the c‐N5− salts are potential building blocks for future energetic materials, their predicted performances are not revolutionary, fall within the range of CHNO compounds, and do not approach those expected for polynitrogen cations or neutral polynitrogens. Our lattice energy calculations also indicate that the previously reported experimental value of 114.28±0.84 kJ mol−1 for the enthalpy of formation of solid NH4N3 may need revision.