Stable xenon nitride at high pressures

Nitrides in many ways are fascinating since they often appear as superconductors, high-energy density, and hard materials. Though there exist a large variety of nitrides, noble gas nitrides are missing in nature. Pursuit of noble gas nitrides has therefore become the subject of topical interests, but remains as a great challenge since molecular nitrogen (N-2, a major form of nitrogen) and noble gases are both inert systems and do not interact at normal conditions. We show through a first-principles swarm-structure search that high pressure enables a direct interaction of N-2 and xenon (Xe) above 146 GPa. The resultant Xe nitride has a peculiar stoichiometry of XeN6, possessing a high-energy density of approximately 2.4 kJ g(-1), rivaling that of the modern explosives. Structurally, XeN6 is intriguing with the appearance of chaired N-6 hexagons and unusually high 12-coordination of Xe bonded with N. Our work opens up the possibility of achieving Xe nitride with superior high-energy density whose formation is long sought as impossible.