Question

What do you mean by bidentate and ambidentate ligands? Give one example of each.

Hint:

Bidentate ligands increase stability of complexes (chelation effect); ambidentate ligands cause linkage isomerism.

Answer 1

Bidentate ligands.
These have two donor atoms that coordinate simultaneously to the metal ion. Example: Ethylenediamine (en), \(\text{H}_2\text{N-CH}_2\text{CH}_2\text{NH}_2\).
Ambidentate ligands.
These have two donor atoms but can bind through only one at a time, leading to linkage isomerism. Example: NO\(_2^-\) (binds via N or O).
Conclusion.
Bidentate ligands → two donor atoms at once; Ambidentate ligands → two possible donor atoms, but only one attaches.