Question

Which of the following is a heteroleptic complex?

• A. \( [Co(NH_3)_6]^{3+} \)
• B. \( [Fe(CN)_6]^{4-} \)
• C. \( [Co(SCN)_4]^{2-} \)
• D. \( [Co(NH_3)_4Cl_2]^+ \)
• E. \( [Co(CN)_6]^{3-} \)

Hint:

Same ligands → homoleptic, Different → heteroleptic.

Answer 1

The Correct Option is D

Step 1: Understanding Homoleptic and Heteroleptic Complexes:
Coordination complexes can be classified based on the types of ligands attached to the central metal ion.
Homoleptic complexes are those in which the central metal ion is coordinated to only one type of ligand. For example, [Fe(CN)\(_6\)]\(^{4-}\) has only CN\(^-\) ligands.
Heteroleptic complexes are those in which the central metal ion is coordinated to more than one type of ligand. For example, [Co(NH\(_3\))_4Cl\(_2\)]\(^+\) has both NH\(_3\) and Cl\(^-\) ligands.
Step 2: Analyzing the Options:
(A) [Co(NH\(_3\))_6]\(^{3+}\): Only one type of ligand (NH\(_3\)). This is homoleptic. (Note: The formula seems incomplete in the OCR, but assuming it's [Co(NH\(_3\))_6]\(^{3+}\)).
(B) [Fe(CN)\(_6\)]\(^{4-}\): Only one type of ligand (CN\(^-\)). This is homoleptic.
(C) [Co(SCN)\(_4\)]\(^{2-}\): Only one type of ligand (SCN\(^-\)). This is homoleptic.
(D) [Co(NH\(_3\))_4Cl\(_2\)]\(^+\): Two different types of ligands are present: ammonia (NH\(_3\)) and chloride (Cl\(^-\)). This is heteroleptic.
(E) [Co(CN)\(_5\)]\(^{3-}\): Only one type of ligand (CN\(^-\)). This is homoleptic. (Note: The formula seems incomplete, maybe [Co(CN)\(_5\)H\(_2\)O]\(^{2-}\) or similar, but as written, it's homoleptic).
Step 3: Final Answer:
The complex [Co(NH\(_3\))_4Cl\(_2\)]\(^+\) is a heteroleptic complex because it contains more than one type of ligand.