The Effect of Iron Concentration on the (Remark: Graphics omitted.) Transitions in Iron Compounds. II

Abstract

Hendrickson et al. (Inorg. Chem. 20 (1981) 131) showed that the transition temperature for the (Remark: Graphics omitted.) transition in the spin crossover compound [Fe_xCr_1−x(3-OCH₃-SalEen)₂]PF₆ decreases with increasing the Cr concentration, whereas the transition temperature in [Fe_xCo_1−x(3-OCH₃-SalEen)₂]PF₆ increases with increasing Co concentration. These dilution effects on the (Remark: Graphics omitted.) transitions is studied on the basis of the ligand field theory by taking account of the coupling between d electrons of iron and a lattice strain. The present model clarifies the origins of the two kinds of dilution effects. In the latter case, the lattice contraction is induced by the Co ions. The effect of the contraction of the transition is reasonably treated as the pressure effect. The calculated temperature dependence of the effective magnetic moment for various dopant concentrations reproduces the essential features of the two types of observed results.