Out of the following complex ions, identify heteroleptic complexes:
A. [Co(NH3)5(CO3)]+
B. [Co(NH3)4Cl2]+
C. [Co(NH3)6]3+
D. [CoCl2(en)2]+
E. [Co(en)3]3+
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A, B, D only
A complex in which the metal is bound to only one kind of donor group is homoleptic (e.g. \( \ce{[Co(NH3)6]^{3+}} \)). One in which the metal is bound to more than one kind of donor group is heteroleptic (e.g. \( \ce{[Co(NH3)4Cl2]^{+}} \)).
A. \( \ce{[Co(NH3)5(CO3)]^{+}} \) — Correct. \( \ce{NH3} \) and \( \ce{CO3^{2-}} \): heteroleptic.
B. \( \ce{[Co(NH3)4Cl2]^{+}} \) — Correct. \( \ce{NH3} \) and \( \ce{Cl^{-}} \): heteroleptic.
C. \( \ce{[Co(NH3)6]^{3+}} \) — Incorrect. Only \( \ce{NH3} \): homoleptic.
D. \( \ce{[CoCl2(en)2]^{+}} \) — Correct. \( \ce{Cl^{-}} \) and ethane-1,2-diamine: heteroleptic.
E. \( \ce{[Co(en)3]^{3+}} \) — Incorrect. Only en: homoleptic.
NCERT (2026-27 edition):
Homoleptic and Heteroleptic Complexes
