A Chromium−Vanadyl Ferrimagnetic Molecule-Based Magnet: Structure, Magnetism, and Orbital Interpretation

Abstract

The synthesis, structural characterization, and magnetic properties of a new Prussian blue analogue, the molecule-based ferrimagnet (V IV O)[Cr III (CN) 6 ] 2/3 · 10 / 3 H 2 O ( 1 ) ( T C = 115 K), are presented. The crystal structure is determined from the powder X-ray diffraction diagram using the Rietveld method. The system is cubic, space group Fm 3 m with cell parameter a = 10.490(4) Å. The value of the exchange coupling parameter J (−48 cm - 1 ) between Cr III and V IV O is estimated from the molecular field parameter W, obtained by fitting the |χ M - 1 | = f ( T ) data in the paramagnetic phase of the compound. The dependence of the T C value is analyzed in relation with the connectivity of the molecular precursor, the stoichiometry of the three-dimensional material, and the nature of the constituting metal ions. The T C value of 1 is compared to that of the high- T C ferrimagnet (315 K) V[Cr(CN) 6 ] 0.86 ·2.8H 2 O ( 2 ); the values of the J parameters are almost the same. This allows us to estimate the T C values for other possible vanadium−chromium ferrimagnets.