The New High-Pressure Phases of Nitrogen-Rich Ag–N Compounds

The high-pressure phase diagram of Ag–N compounds is enriched by proposing three stable high-pressure phases (P4/mmm-AgN₂, P1-AgN₇ and P-1-AgN₇) and two metastable high-pressure phases (P-1-AgN₄ and P-1-AgN₈). The novel N₇ rings and N₂₀ rings are firstly found in the folded layer structure of P-1-AgN₇. The electronic structure properties of predicted five structures are studied by the calculations of the band structure and DOS. The analyses of ELF and Bader charge show that the strong N–N covalent bond interaction and the weak Ag–N ionic bond interaction constitute the stable mechanism of Ag–N compounds. The charge transfer between the Ag and N atoms plays an important role for the structural stability. Moreover, the P-1-AgN₇ and P-1-AgN₈ with the high-energy density and excellent detonation properties are potential candidates for new high-energy density species.