The results show that the interactions between Ln 3+ ions and the ligands in the early Ln complexes 1-Ln can be considered as being mostly ionic. The results are consistent with early CW EPR studies of U 3+ and Nd 3+ doped fluorite (and later studies on other inorganic lattices), where superhyperfine coupling to F was observed for the former but not the latter. These are mineral lattices with hard ligands, and we have now shown related effects in molecular species with very soft ligand sets. The results on 1-Ln also contrast with HYSCORE studies of a closely related complex of Yb 3+ , 20 a late Ln complex (4f ), which showed far more significant metal-ligand interactions. This highlights the importance of ligand substituents and Ln ion charge density in controlling the magnitude of 4f metal-ligand interactions, and shows that pulsed EPR spectroscopy is a sensitive probe to study these effects.