Single-crystal magnetic properties of lanthanide complexes. Part I. Tri-iodohexakis(antipyrine)ytterbium

Abstract

The principal magnetic moments of crystals of tri-iodohexakis(antipyrine)ytterbrium (antipyrine is 2,3-dimethyl-1-phenyl-Δ³-pyrazolin-5-one) have been determined in the temperature range 300–90 K. These are interpreted within a free-ion f¹³ basis perturbed by spin–orbit coupling and a crystal field of D_3d symmetry. The general behaviours of theoretical energy levels and magnetic moments as functions of geometry and of the second-, fourth-, and sixth-order crystal-field radial integrals are examined. The experimental susceptibilities are fitted to this model and values for the parameters deduced and correlated with the orbital reduction factor. Information is also obtained from the crystal electronic spectrum at ca. 10,600 cm^–1.