Pressure-induced stability and polymeric nitrogen in alkaline earth metal N-rich nitrides (XN, X = Ca, Sr and Ba): a first-principles study.

Multi-nitrogen or polynitrogen compounds can be used as potential high energy-density materials, so they have attracted great attention. Nitrogen can exist in alkaline earth metal nitrogen-rich (N-rich) compounds in the form of single or double bonds. In recent years, to explore N-rich compounds which are stable and easy to synthesize has become a new research direction.