Magnetic moment (spin only) of octahedron complex having CFSE = -0.8\Delta_o and surrounded by weak — Coordination Compounds Chemistry Question

💡 Solution & Explanation

Step 1: Octahedral crystal field stabilization energy is given by: CFSE = [-0.4 * n(t_2g) + 0.6 * n(eg)] * δ_o. For weak field (high spin) configurations, we calculate the CFSE for different d-electron counts. Step 2: We find that both the d^2 configuration (t_2g^2 eg^0) and the high-spin d^7 configuration (t_2g^5 eg^2) yield a CFSE of exactly -0.8δ_o. Step 3: For d^2, there are 2 unpaired electrons, so μ = \sqrt{2(2+2)} = \sqrt{8} BM. For d^7, there are 3 unpaired electrons, so μ = \sqrt{3(3+2)} = \sqrt{15} BM. Since both magnetic moments are possible, option (c) is correct.