An energetic phase of ZnN6 at ambient conditions

The properties of ZnN6 has been studied under high pressure using first-principles calculations. Three highpressure phases, metallic Cm phase, semiconductor P1, and polymeric nitrogen I41md phases, have been observed at 2.3 GPa, 28 GPa, and 98 GPa, respectively. Through theoretical calculations indicate that the I41md phase is thermodynamically stable at 0 GPa, while the Cm phase and P1 phase are not stable until the pressure of 20 GPa. Under the action of pressure, nitrogen atoms in the I41md phase form a new network structure. There is a certain charge transfer between zinc atoms and nitrogen atoms, thus forming the interaction between anions and cations, which also determines the stability of the I41md phase. Moreover, the N atom is in the sp2 and sp3 hybridization. The energy density of the I41md phase is about 4.70 kJ/g, which determines that it can be regarded as a promising HEDMs candidate.