JEE MainChemistryCoordination Compounds
Given below are five coordination complexes: (A) [ Mn ( CN )₆]³⁻ (B) [ Cr ( H ₂ O )₆]²⁺ (C) [ Fe ( H ₂ O )₆]²⁺ (D) [ Cr ( CN )₆]⁴⁻ (E) [ CoF ₆]³⁻ Identify the complexes in which the central metal ion has a t_ 2g ^4 e_g^0 electronic configuration.
Options
- A(A), (B) and (D) only
- B(C) and (E) only
- C(A) and (C) only
- D(A) and (D) only
Correct answer
D. (A) and (D) only
Step-by-step solution
The electronic configuration of the central metal ion in each complex is determined by its oxidation state and the nature of the ligand (strong or weak field). (A) [ Mn ( CN )₆]³⁻ : Mn is in +3 oxidation state. Mn ³⁺ has a 3d^4 configuration. Since CN ^- is a strong field ligand, pairing occurs, resulting in t_ 2g ^4 e_g^0 . (B) [ Cr ( H ₂ O )₆]²⁺ : Cr is in +2 oxidation state. Cr ²⁺ has a 3d^4 configuration. H ₂ O is a weak field ligand, so it forms a high spin complex with configuration t_ 2g ^3 e_g^1 . (C) [ Fe