Cage-like salt with N-N single bonds

Abstract

All-nitrogen salts have attracted much attention because of their potential applications as high-energy density materials for explosive or propulsion. Here, we design a cage-like salt Be3N10 with pure N-N single bonds via releasing the pressure of the cage-like diamondoid “N10”, high-pressure phase of nitrogen, and introducing beryllium atoms to stabilize the crystal. At ambient conditions, Be3N10 comprises two anions and six Be2+ cations in a unit cell with high space symmetry (space group ). The Be3N10 salt is kinetically and thermodynamically stable with a 3.06 eV band gap at 0 GPa and room temperature. Further analysis of the chemical bonding pattern and electronic properties reveals that the introduced Be atoms contribute electrons to passivate the dangling bonds of the N10 cluster, and stabilize the system through both Coulomb interactions and covalent bonds. The outstanding properties, including high-energy density (5.75 kJ/g), high nitrogen content (83.8%), and high dynamical stability, make Be3N10 a promising high-energy density material. Our work represents a significant step toward the all-nitrogen salt with pure N-N single bonds.