Ligands are the neutral or negatively charged entities surrounding the central metal atom of the coordination complex which possesses at least one unshared pair of electrons.

Based on the number of donor sites of these ligands, Ligands are classified as:

Unidentate ligands: These Ligands which have only one donor site are called unidentate ligands.

Example: F^-,Cl ^– etc

Didentate ligands: These Ligands which have only two donor site are called didentate ligands.

Example: Ethane-1,2-diamine, Oxalate ion etc

Ambidentate ligands: These ligands which can attach them with the central metal atom by two different atoms are called as ambidentate ligands.

Example: