Question

What is meant by bidentate ligands? Illustrate with examples.

Answer 1

The ligands which possess two donor atoms and can form two coordinate bonds with the central metal atom or ion are called bidentate ligands. Examples of bidentate ligands:

1. Ethylenediamine (en): Ethylenediamine is a common bidentate ligand with two nitrogen atoms (each with a lone pair of electrons) that can coordinate to the metal ion.
   
   In the complex [Cu(en)₂]²⁺ ethylenediamine acts as a bidentate ligand by coordinating to the copper ion via the two nitrogen atoms.
2. Glycine (NH₂CH₂COOH): Glycine is an amino acid that can act as a bidentate ligand due to the lone pairs of electrons on both the nitrogen (amino group) and oxygen (carboxyl group).
   
   In the complex [Cu(gly)₂]²⁺ glycine acts as a bidentate ligand by coordinating to the copper ion via both the nitrogen and oxygen atoms.