Theoretical study for high-energy-density compounds from cyclophosphazene III. A quantum chemistry study: High nitrogen-contented energetic compound of 1,1,3,3,5,5,7,7-octaazido-cyclo-tetraphosphazene: N₄P₄(N₃)₈

Molecular structure, vibrational frequencies and infrared intensities of 1,1,3,3,5,5,7,7-octaazido-cyclo-tetraphosphazene have been studied employing HF, B3LYP and B3PW91 methods using 6-31G^* basis set. The study showed that this molecule has non-planar structure and there is no imaginary frequency. Furthermore, there exist four sets of special P{double bond, long}N bonds in the P₄N₂₈ ring; the P{double bond, long}N bonds and the azide groups conjoint to them have special characters. The NBO population analysis was used to help us understand the interactions between donor orbit and acceptor orbit in the nitrogen phosphorus systems. Furthermore, three methods with the same basis set are further employed to calculate the heats of formation for the compound. Crown