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

Step 1: Understand ambidentate ligand.
An ambidentate ligand is a ligand that has two different donor atoms. It can coordinate through either of the two donor atoms, but not both at the same time.

Step 2: Analyze thiocyanate ion.
Thiocyanate ion is: \[ \ce{SCN^-}. \] It can coordinate through sulphur: \[ \ce{-SCN} \] or through nitrogen: \[ \ce{-NCS}. \] Therefore, it is an ambidentate ligand.

Step 3: Check other options.
Oxalate is a bidentate ligand. Ethylenediamine or ethane-1,2-diamine is also bidentate. They coordinate through two donor atoms simultaneously. So they are not ambidentate. Hence, the correct answer is: \[ \text{Thiocyanate ion}. \]