Question

What is an ambidentate Ligand? Give examples.

Answer 1

Hint: A ligand is an ion or a molecule, which donates a pair of its electrons to the central metal atom or ion to form a new bond with the metal finally results in the formation of the coordination complex. There are several types of ligands, based on the donation of electrons like monodentate ligand, ambidentate ligand, polydentate ligand etc.

Complete step-by-step answer:
Monodentate ligand is a type of ligand that has only one atom that forms a bond directly with the central atom in a complex.
Ambidentate Ligand is also a monodentate ligand but has two or more donor atoms but only one donor atom of the ligand forms the bond with the metal during complex formation.
For example, nitro ligand (\[NO_{2}^{-}\]) ​ has two donor atoms Nitrogen (N) and Oxygen (O). But only one donor atom forms bond to the metal through the following way
 \[M-ONO\] or \[M-N{{O}_{2}}\].(here, M = metal)
One more ambidentate ligand is, \[SC{{N}^{-}}\]. It has two donor atoms Sulphur (S) and Nitrogen (N) but only one atom can form bond with the metal through the following way
\[M-SCN\] or \[M-NCS\]
In the same way, \[C{{N}^{-}}\](cyanide ion) has two donor atoms Carbon (C) and Nitrogen (N) but only one can form bond with the metal through the following way
\[M-CN\]or \[M-NC\]

Note: Don’t be confused with poly dentate ligand and ambidentate ligands. Both are not the same.
Polydentate ligand: A polydentate ligand is a type of ligand that coordinates to the metal center through two or more than two atoms, forming two or more than two bonds.
Example: EDTA (Ethylene Diamine Tetra Acetic acid) is the best example for polydentate ligand. EDTA forms six bonds with the metal. So, it is also called a hexadentate ligand.