Question

Which one of the following is an ambidentate ligand?

• A. Oxalate
• B. Ethylenediamine
• C. Thiocyanate ion
• D. Ethane-1,2-diamine

Hint:

Ambidentate ligands can attach through two different atoms. Examples include \(\ce{NO2^-}\), \(\ce{SCN^-}\), and \(\ce{CN^-}\).

Answer 1

The Correct Option is C

The question involves identifying an ambidentate ligand from the given options. To solve this, we'll first understand what an ambidentate ligand is and then analyze each option to find the correct answer.

Definition: Ambidentate ligands are those that can bind to the central metal atom through two different atoms, providing a choice of binding sites.

Now, let's evaluate each option:

1. Oxalate: This ligand has two oxygen atoms that coordinate simultaneously to the metal center, acting as a bidentate ligand. It is not ambidentate because both binding sites are identical.
2. Ethylenediamine: Known as a classic bidentate ligand, ethylenediamine coordinates through its two nitrogen atoms. They are not ambidentate, as they do not provide different atoms for coordination.
3. Thiocyanate ion (SCN^-): This ligand can bind to a metal center through the sulfur atom or the nitrogen atom, making it an ambidentate ligand. It provides alternative coordination sites, highlighting its ambidentate nature.
4. Ethane-1,2-diamine: Like ethylenediamine, this is also a bidentate ligand coordinating via nitrogen atoms, not offering different binding sites for ambidentatge ability.

Hence, the correct answer is the Thiocyanate ion (SCN^-), as it can attach to the metal through two possible donor sites (S or N).