Just How Many Ligands Can Fit around a Metal Atom

3 Just How Many Ligands Can Fit around a Metal Atom  

This is a fairly easy question to answer. If we think about elements such as carbon, nitrogen and oxygen, we know that their valency can be explained by the importance of filling the outer valence 

Transition metals have to fill an s orbital, three p orbitals and five d orbitals. This requires eighteen electrons. This is the eighteen-electron rule. These electrons must either belong to the metal atom already or must be supplied by the ligand. We must also adjust for the charge. 

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