Thermal Decomposition of Energetic Materials XXIV. A comparison of the crystal structures, IR spectra, Thermolysis and impact sensitivities of nitroguanidine and trinitroethylnitroguanidine

The crystal structure of trinitroethylnitroguanidine (TNENG) was determined by X‐ray diffraction for comparison with nitroguanidine (NGu). Pertinent crystal parameters are: orthorhombic, Pbca, a = 14.611 (7) Å, b = 11.973 (5) Å, c = 11.452 (5) Å, V = 2003 (2) Å 3 , Z = 8, D(calcd) = 1.758 g/cm 3 , R(F) = 6.30%, R(wF) = 6.58%. A hydrogen bonded network like that present in NGu is largely responsible for the lattice cohesion of TNENG. The IR spectrum of the condensed phase using slow thermolysis, and the gas phase using slow and fast thermolysis, suggests that parallel CN and NN bond fission reactions take place in both TNENG and NGu. The calculated and experimental values of the impact sensitivity of TNENG and NGu are compared. We conclude that the impact sensitivity and the thermal decomposition of TNENG are dominated by the characteristics of the C(NO 2 ) 3 group. The intermolecular hydrogen bonding that may desensitize nitroguanidine to impact has essentially no stabilizing effect on TNENG.