Pre-Transition Metals | Lanthanides | Transition Metals |
Essentially Monovalent - show Group (n+) oxidation state | Essentially Monovalent (+3) +2/+4 for certain configurations | Show Variable Valence (extensive redox chemistry) control by environment ~ ligands, pH etc
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Periodic trends - dominated by (effective nuclear) charge at noble gas config. (i.e. on group valence) | Lanthanide Contraction of Ln3+ | Size changes of Mn+ less marked |
Similar Properties for a given group (differentiated by size) | Similar Properties (differentiated by size) | Substantial Gradation in Properties |
widespread on earth | common mineralogy | diverse mineralogy |
No Ligand Field Effects | Insignificant Ligand Field Effects | Substantial Ligand Field Effects |
Always 'hard' (O, Hal, N donors) (preferably negatively charged) | Always 'hard' (O, Hal, N donors) (preferably negatively charged) | Later (increasingly from Fe&endash;Cu)/heavier metals may show a 'soft' side |
'Ionic' Æ 'Covalent' Organometallics | 'Ionic' Organometallics | 'Covalent' Organometallics |
No ¼-Ligand Effects | Paucity of ¼-Ligand Effects | ¼-Acceptor Ligands Æ Extensive Chemistry |
Poor Coordination Properties (C.N. determined by size) | High Coordination Numbers (C.N. determined by size) | Extensive Coordination C.N. = 6 is typical maximum (but many exceptions) |
Flexibility in Geometry | Flexibility in Geometry | Fixed (by Ligand Field effects) Geometries |
No Magnetism from the metal ions - noble gas configurations of ions | Free Ion-like Magnetism ground state magnetism | Orbital Magnetism 'Quenched' by Ligand Fields excited J-states populated |
'Ionic' compound formulations Þ large HOMO-LUMO gaps Þ UV CT spectra | Weak, Narrow Optical Spectra forbidden, unfacilitated transitions | Stronger, Broader Optical Spectra forbidden transitions vibronically-assisted |