A chromium-vanadyl ferrimagnetic molecule-based magnet: Structure, magnetism, and orbital interpretation

The synthesis, structural characterization, and magnetic properties of a new Prussian blue analogue, the molecule-based ferrimagnet (V{sup IV}O)[Cr{sup III}(CN){sub 6}]{sub 2/3}{center_dot}{sup 10}/{sub 3}H{sub 2}O (1) (T{sub 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 Fm3m with cell parameter a = 10.490(4) {angstrom}. The value of the exchange coupling parameter J ({minus}48 cm{sup {minus}1}) between Cr{sup III} and V{sup IV}O is estimated from the molecular field parameter W, obtained by fitting the {vert_bar}{chi}{sub M}{sup {minus}1}{vert_bar} = f(T) data in the paramagnetic phase of the compound. The dependence of the {Tc} 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 {Tc} value of 1 is compared to that of the high-{Tc} ferrimagnet (315 K) V[Cr(CN){sub 6}]{sub 0.86}{center_dot}2.8H{sub 2}O (2); the values of the J parameters are almost the same. This allows the authors to estimate the {Tc} values for other possible vanadium-chromium ferrimagnets.