GKFix MCQ Question

Why do the complexes [Fe(CN)6]^4- and [Fe(CN)6]^3- exhibit different magnetic properties?

• A. Because CN- is a ligand.
• B. Because they have different charges.
• C. Because Fe^2+ (d^6) and Fe^3+ (d^5) have different numbers of d-electrons, leading to different electron configurations and numbers of unpaired electrons in the strong field environment of CN- ligands.
• D. Because they are both iron complexes.