Theoretical DFT calculations using GGA+U and HSE06 frameworks enabled vibrational mode assignment and partial (atomic) phonon DOS determination in KAgF3 perovskite, a low-dimensional magnetic fluoroargentate(II). Twelve bands in the spectra of KAgF3 were assigned to either IR active or Raman active modes, reaching excellent correlation with experimental values (R2 > 0.997). Low-temperature Raman measurements indicate that the intriguing spin-Peierls-like phase transition at 230 K is an order–disorder transition and it does not strongly impact the vibrational structure of the material.

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With the use of lattice dynamics calculation within the hybrid HSE06 framework we were able to understand the vibrational spectra of MAgF3 (M = K, Rb, Cs) compounds.

High‐temperature solid‐state reaction between orthorhombic AgF2 and monoclinic CuF2 (y=0.15, 0.3, 0.4, 0.5) in a fluorine atmosphere resulted in coexisting solid solutions of Cu‐poor orthorhombic and Cu‐rich monoclinic phases with stoichiometry Ag1−xCuxF2. Based on X‐ray powder diffraction analyses, the mutual solubility in the orthorhombic phase (AgF2 : Cu) appears to be at an upper limit of Cu concentration of 30 mol % (Ag0.7Cu0.3F2), while the monoclinic phase (CuF2 : Ag) can form a nearly stoichiometric Cu : Ag=1 : 1 solid solution (Cu0.56Ag0.44F2), preserving the CuF2 crystal structure. Experimental data and DFT calculations showed that AgF2 : Cu and CuF2 : Ag solid solutions deviate from the classical Vegard's law. Magnetic measurements of Ag1−xCuxF2 showed that the Néel temperature (TN) decreases with increasing Cu content in both phases. Likewise, theoretical DFT+U calculations for Ag1−xCuxF2 showed that the progressive substitution of Ag by Cu decreases the magnetic interaction strength |J2D| in both structures. Electrical conductivity measurements of Ag0.85Cu0.15F2 showed a modest increase in specific ionic conductivity (3.71 ⋅ 10−13±2.6 ⋅ 10−15 S/cm) as compared to pure AgF2 (1.85 ⋅ 10−13±1.2 ⋅ 10−15 S/cm), indicating the formation of a vacancy‐ or F adatom‐free metal difluoride sample.

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