High-Tc Molecular-Based Magnets: Ferrimagnetic Mixed-Valence Chromium(III)-Chromium(II) Cyanides with Tc at 240 and 190 Kelvin

Molecular-based magnets with high magnetic-ordering temperatures, T c , can be obtained by mild chemistry methods by focusing on the bimetallic and mixed-valence transition metal µ-cyanide of the Prussian blue family. A simple orbital model was used to predict the electronic structure of the metal ions required to achieve a high ordering temperature. The synthesis and magnetic properties of two compounds, [Cr 5 (CN) 12 ].10H 2 O and Cs 0.75 [Cr 2.125 (CN) 6 ]·5H 2 O, which exhibited magnetic-ordering temperatures of 240 and 190 kelvin, respectively, are reported, together with the strategy for further work.