Hydrogen Bond and π-π Stacking Interaction: Stabilization Mechanism of Two Metal -N -Containing Energetic Materials.

In recent years, -N has attracted extensive attention because all-nitrogen high-energy-density materials (HEDMs) have been expected to reach a TNT equivalent of over 3.0. However, for -N -containing HEDMs, the stabilization mechanism has remained enigmatic. In this study, two typical -N -containing metal hydrates, [Na(HO)(N)]·2HO (Na--N ) and [Mg(HO)(N)]·4HO (Mg--N ), are selected to gain insights into the factors affecting their stability by the first-principles method. Both binding/lattice energy calculations and density of states analysis show that Mg--N is more stable than Na--N . Hydrogen bonding is the main stabilization mechanism for stabilizing crystals and -N . Two types of hydrogen bonds, O-H···O and O-H···N, are clarified, which construct a 3D hydrogen bond network in Mg--N and an intralayer 2D hydrogen bond network in Na--N . Moreover, nonuniform stress causes distortion of -N . Comparing the two samples, the distortion degree of -N is higher in Na--N , which indicates that -N decomposition is easier. These findings will enhance the future prospects for the design and synthesis of -N -containing HEDMs.