Which of the following complex is homoleptic?

Solution

Chemistry ma’am · 3 steps

Look inside the square bracket and ask one thing: is every ligand on the metal the same?

1. Homoleptic or heteroleptic. A complex is homoleptic when the metal is bound to only one kind of ligand. If two or more different ligands are attached, it is heteroleptic.

   Complex	Ligands on the metal	Kinds of ligand	Type
   [Ni(NH₃)₂Cl₂]	2 NH₃, 2 Cl⁻	2	heteroleptic
   [Co(NH₃)₄Cl₂]⁺	4 NH₃, 2 Cl⁻	2	heteroleptic
   [Fe(NH₃)₄Cl₂]⁺	4 NH₃, 2 Cl⁻	2	heteroleptic
   [Ni(CN)₄]²⁻	4 CN⁻	1	homoleptic

2. Ignore the rest. The metal, its oxidation state and the overall charge do not matter here. Only the variety of ligands decides the answer.
3. So. Only [Ni(CN)₄]²⁻ has a single type of ligand, so (d) is the homoleptic complex.

The idea to keep. Homo means same: one kind of ligand only, however many of them there are. Even one different ligand in the bracket makes the complex heteroleptic.

Answer from the NTA final answer key. Solution by PrepWiser.