JEE Main 2025 — Coordination Compounds Question with Solution

Homoleptic complexes are complexes with identical ligands attached to the central metal atom.

(A) $$[Fe{O}_4{]}^{2-}$$ - Homdeptic

Central metal : Fe

IN this complex, Fe is in +6 oxidation state.

{oxidation state : $$x+4(-2)=-2$$

$$x-8=-2$$

$$x=-2+6=+6$$

Configuration of $$Fe-d^6{s}^2$$

Configuration of $$Fe(+6)-c{l}^2$$

Iron has even number of d electrons. So, it is not correct.

(B) $$[Fe(N{)}_6{]}^{3-}$$ - Homoleptic

Central metal : Fe

In this complex, the oxidation state of Fe is +3

Oxidation state :

$$x+6(-1)-3$$

$$x-6=-3$$

$$x=-3+6=+3$$

Configuration of $$Fe-d^6{s}^2$$

Configuration of $$Fe(+3)-d^5$$

Iron has odd number of d electrons.

So, it is correct.

(C) $$[Fe(CN{)}_{5}NO{]}^{2-}$$ - Not homoleptic

This complex has different type of ligands.

$$[CoC{l}_4{]}^{2-}$$ - Homoleptic

Central metal - Co

In this complex, the oxidation state of Co is +2

Oxidation state:

$$x+4(-1)=-2$$

$$x-4=-2$$

$$x=-2+4=+2$$

Configuration of $$Co-d^7{s}^2$$

Configuration of $$Co(+2)-d^7$$

Cobalt has odd number of d electrons.

So, it is correct.

(E) $$[Co(H_{2}O{)}_3{F}_3]$$ - Not homoleptic,

It has different type of ligands.

Complexes B and D are homoleptic complexes with odd number of d electrons in the central metal. So, correct answer is

(B) and (D) only.