Comparative computational study of antiferromagnetic and mixed-valent diamagnetic phase of AgF2: Crystal, electronic and phonon structure and p-T phase diagram

Crystal and electronic structure, lattice dynamics thermodynamic stability of little known mixed-valent diamagnetic Ag1+Ag3+F4 ? form AgF2 is thoroughly examined for the first time compared with well-known antiferromagnetic Ag2+F2 ? within framework Density Functional Theory based methods, phonon direct method quasiharmonic approximation. Computed equations state, bulk moduli, densities states, band structures including analysis optically active modes p–T phase diagram ?–? system are presented. This study demonstrates that thermodynamically preferred over at all temperatures pressures its existence but simultaneously dynamically stable in much broader pressure range. The discussed context isostructural ternary metal fluorides isoelectronic oxides NaCuO2 – reference Cu3+ compound corresponding to fully overdoped high-temperature oxocuprate superconductor.