The most stable ion is : — Coordination Compounds Chemistry Question

💡 Solution & Explanation

Step 1: Compare the stability of the complex ions based on oxidation states and ligand field strengths. Step 2: Fe^3+ has a higher charge density than Fe^2+, which generally forms more stable complexes. Step 3: CN^- is an exceptionally strong-field ligand that forms extremely stable cyano complexes through both strong sigma donation and pi back-bonding. Thus, [Fe(CN)6]^3- is the most stable ion, matching option (b).