Polydentate ligand

Definition

A polydentate ligand is a molecule or ion that can form multiple bonds to a single metal ion simultaneously. It has two or more donor atoms that can coordinate to the metal center.

5 Must Know Facts For Your Next Test

1. A polydentate ligand forms chelate complexes with metal ions, creating rings that include the metal ion.
2. The stability of a complex generally increases with the number of bonds a polydentate ligand forms with the metal.
3. Ethylenediaminetetraacetate (EDTA) is an example of a hexadentate ligand, meaning it can form six bonds to a metal ion.
4. Polydentate ligands are also known as chelating agents because they 'claw' onto the metal ion.
5. The denticity of a ligand refers to the number of donor atoms it has available to bind to a central metal atom.

Review Questions

Related terms

Monodentate Ligand: A monodentate ligand is a molecule or ion that coordinates to a single central atom through one donor atom.

Chelation: Chelation involves the formation of two or more separate coordinate bonds between a polydentate ligand and a single central atom.

Coordination Number:

The coordination number is the total number of coordinate bonds formed between central metal ions and its ligands in a complex.