New high-pressure phases of nitrogen-rich Zr–N compounds

The stoichiometries and crystal structures of Zr–N system at high pressure are systematically investigated based on the first-principles method and the evolutionary algorithm. Three nitrogen-rich compounds containing polymeric nitrogen are identified, including [Formula: see text]-ZrN 6 , [Formula: see text]-ZrN 12 , and [Formula: see text]-ZrN 12 . These phases exhibit a variety of polymeric nitrogen configurations, including N 14 ring-based layers and armchair-N chains. [Formula: see text]-ZrN 6 and [Formula: see text]-ZrN 12 stand out as prospective high-energy density materials with energy densities of 3.39[Formula: see text]kJ/g and 3.22[Formula: see text]kJ/g. Their explosive properties are remarkable, with detonation pressures 5–8 times that of TNT (19[Formula: see text]GPa) and a velocity 1–2 times that of TNT (6.90[Formula: see text]km/s). The stability of these Zr–N compounds is attributed to the interplay between strong N–N covalent and weak ionic Zr–N interactions.