Stabilizing the N5 ring is essential to synthesize the polynitrogen compounds that have attracted great attention due to their potential applications as high-energy-density materials. Recent breakthrough of synthesizing the metal pentazolate hydrate complexes through hydrogen-bonding interactions with water provides a practical way to stabilize the N5 ring at ambient conditions. However, the decomposition mechanisms of N5 ring remains unclear. Here we report quantum mechanics (QM) based reaction studies to determine the atomistic reaction mechanisms for the initial decompositions of N5 ring. First we carried out molecular dynamics simulations using forces from density functional theory (DFT-MD), which finds that the reactions are initiated by N5 ring breakage or water dissociation. Then we performed nudged elastic band (NEB) calculations to obtain the critical reaction steps for the N5 decomposition. The bonding analysis indicates that metal-N bond plays an important role in N5 decomposition. In addition, the water environment plays an important role in stabilizing the N5 ring in the condensed phase. Our simulation results suggest that to improve the thermal stability of N5 ring it is important to avoid the metal-N bonds.

Initial decomposition reactions of metal pentazolate hydrates from quantum mechanics simulations

256th National Meeting (2018)

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