The magnetic moment of [MnX4]^2- is 5.9 BM. The geometry of the complex ion is :<br>(X = monodentate — Coordination Compounds Chemistry Question

💡 Solution & Explanation

Step 1: A spin-only magnetic moment of 5.9 BM corresponds to exactly 5 unpaired electrons (n = 5). Step 2: Mn^2+ is a 3d^5 transition metal ion. In a tetrahedral crystal field with weak-field halide (X^-) ligands, the electronic configuration is e^2 t_2^3, which contains 5 unpaired electrons. In a square planar field (dsp^2), at least one d-orbital must be vacated by pairing, preventing all 5 electrons from remaining unpaired. Step 3: Therefore, only a tetrahedral geometry can account for 5 unpaired electrons, which corresponds to option (a).