For instance, Rinehart and Long 3 , discussing the ashpericities of the electron density of the magnetic states in trivalent lanthanide ions calculated by Sievers some 20 years earlier, pointed out how a proper axial (equatorial) distribution of the charge den-sity in the coordinating ligands could be harnessed to synthesise Ln complexes with large magnetic anisotropy, by stabilizing the appropriate oblate (prolate) charge density distribution in that specific ion. This simple but insightful observation, based on the assumption of purely ionic bonding interactions between metal and ligand, has proven rather useful in guiding synthetic chemists towards ever more efficient Ln-based SMMs.