Cage-like salt with N-N single bonds

¹ School of Physics and Electronic Engineering, Linyi University - Linyi 276005, PRC
² Department of Physics and Engineering Physics, University of Tulsa - Tulsa, OK 74104, USA
³ Beijing Computational Science Research Center - Beijing 100084, PRC

^(a) lijianfu@lyu.edu.cn (corresponding author)
^(b) wxl@lyu.edu.cn (corresponding author)

Received: 16 October 2018
Accepted: 17 December 2018

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.