Posted: Tue Nov 21, 2017 6:42 pm
Does the formation of a chelate require that the ligand is polydentate?
Posted: Tue Nov 21, 2017 7:30 pm
I believe that's usually true but there are exceptions. For example a bidentate ligand such as ethylenediamine can bind to a metal such as Ni^2+ to form a five-membered ring with is a chelate ring. But complexes that contain polydentate ligands are called chelate complexes. Polydentate ligands are significantly more stable than bidentates though which is referred to as the chelate effect. So it's pretty safe to say, polydentates are preferred when chelate complexes are formed.