Theoretical studies on stability and pyrolysis mechanism of salts formed by N and metallic cations Na, Fe and Ni.

The salts formed by N and metallic cations (Na, Fe and Ni) may be potential candidates for superior energetic materials and were studied with the density functional theory B3LYP method and ab initio molecular orbital theory MP2 method using the 6-31G* and LanL2DZ basis sets. Thermal dissociations of these salts are initiated by breaking of the N ring, and those of Fe(N) and Ni(N) proceed sequentially through two transition states. In gas phase, the activation barriers ( Es, in kJ/mol) of thermal dissociations decrease in the order of N > NaN > HN > Ni(N) > Fe(N). Products of initial pyrolysis of these salts are N and metallic azide. The frontier orbital energy gaps (in eV) are N (8.27) > HN (7.40) > NaN (5.10) > Fe(N) (4.92) > Ni(N) (3.43). The more stable salt has the smaller electron transfer between the cation and anion. [ABSTRACT FROM AUTHOR]