Which of the following octahedral complex ions is diamagnetic? — Coordination Compounds Chemistry Question

💡 Solution & Explanation

I need to identify which octahedral complex ion is diamagnetic. However, the answer options (A, B, C, D) aren't provided in your question. **General approach to solve this:** A complex is **diamagnetic** when it has **no unpaired electrons** (all electrons paired up). **Step-by-step reasoning:** 1. **Determine the metal's oxidation state** and count d-electrons 2. **Apply crystal field splitting** for octahedral geometry (d-orbitals split into $t_{2g}$ and $e_g$ levels) 3. **Fill electrons following Hund's rule** for weak field (high spin) or pairing for strong field (low spin) 4. **Check for unpaired electrons**: - If all electrons are paired → **diamagnetic** - If unpaired electrons exist → **paramagnetic** **Common diamagnetic octahedral complexes:** - $[Co(NH_3)_6]^{3+}$ (Co³⁺, d⁶ low spin): $t_{2g}^6 e_g^0$ ✓ - $[Fe(CN)_6]^{4-}$ (Fe²⁺, d⁶ low spin): $t_{2g}^6 e_g^0$ ✓ - $[Ni(CN)_4]^{2-}$ is square planar (not octahedral) - $[MnO_4]^-$ and $[FeF_6]^{3-}$ are paramagnetic **To confirm your answer A:** Please share the options, and I'll identify which specific complex is diamagnetic and explain why others are paramagnetic.