Which of the following complex(s) can not exhibit both geometrical and optical isomerism ? — Coordination Compounds Chemistry Question

💡 Solution & Explanation

Step 1: In the complex [Co(NH3)5CO3]ClO4, Cobalt is coordinated to five NH3 molecules and one monodentate carbonate (CO3^2-) ligand, giving a coordination number of 6. Step 2: The perchlorate ion (ClO4^-) has a -1 charge, making the complex cation [Co(NH3)5CO3]^+. The oxidation state of Co is: x + 5(0) - 2 = +1 => x = +3. Co^3+ is a 3d^6 transition metal ion. Step 3: In the presence of strong-field NH3 ligands, Co^3+ (3d^6) forms a low-spin octahedral complex (t_2g^6 eg^0) with all electrons paired, resulting in 0 unpaired d-electrons. Thus, the parameters are 6, 3, 6, and 0 respectively, matching option (d).