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.