Which of the following complexes is heteroleptic?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \([Fe(NH_3)_4Cl_2]^+\)
Complexes are classified by the kinds of ligands around the metal. A complex in which the metal is bound to only one kind of donor group is homoleptic; one in which it is bound to more than one kind is heteroleptic.
In \( \ce{[Fe(NH3)4Cl2]+} \) iron carries two kinds of ligands, four \( \ce{NH3} \) molecules and two \( \ce{Cl-} \) ions, so it is heteroleptic.
Why the other options are incorrect
Option (2) \([Cr(NH_3)_6]^{3+}\) — Incorrect. All six ligands are \( \ce{NH3} \): homoleptic.
Option (3) \([Co(NH_3)_6]^{3+}\) — Incorrect. All six ligands are \( \ce{NH3} \): homoleptic.
Option (4) \([Mn(CN)_6]^{4-}\) — Incorrect. All six ligands are \( \ce{CN-} \): homoleptic.
NCERT (2026-27 edition):
Homoleptic and Heteroleptic Complexes
