Why is the graph not a straight line?
CFSE’s (Crystal Field Stabilisation Energy’s) The metal hexaaqua complexes which lie above the dotted line: • have larger hydration energies than might be expected • hydration reactions for Ti, V, Cr, Fe, Co, Ni, and Cu are more exothermic than expected • hexaaqua complexes are more stable than expected • ‘extra’ stability can be rationalised by looking at the CFSE’s for the complexes Water is a weak field ligand and [M(OH2)6]2+ ions are all high spin.
