Magnetic Properties of Substitutional Solid Solutions of Zinc(II)-Manganese(II) Tetrachloride with Triphenylphosphonium Ph3PH2Zn1–xMnxCl4

A series of solid solutions Ph3PH2Zn1–xMnxCl4 (0 ≤ x ≤ 1), where Ph3PH is triphenylphosphonium, has been obtained. The solid solutions crystallize in the monoclinic space group P21/n with similar unit cell parameters. The change in unit cell volume upon substitution follows Vegard’s law, in accordance with Hume–Rothery rules for substitutional solid solutions. Electron paramagnetic resonance (EPR) spectroscopy reveals that a decrease in Mn(II) ion concentration leads to an increase in the zero-field splitting parameter and the appearance of a well-resolved hyperfine structure in the spectra. The results demonstrate the possibility of tuning the structural and magnetic properties in zinc(II)-manganese(II) solid solutions and the extreme sensitivity of the exhibited properties to slight changes in the metal ion environment. The observed effects are confirmed by quantum chemical calculations using density functional theory and are consistent with crystal field theory.