Consider the following complex ions: [ Ni(CN) ₄]²⁻ , [ Fe(CN) ₆]³⁻ , [ Cu(H ₂ O) ₆]²⁺ , and [ Co(CN) ₆]³⁻ . The complex ions that are expected to show diamagnetic behavior at room temperature are:

Step-by-step solution

For [ Ni(CN) ₄]²⁻ , the oxidation state of Ni is +2 . The electronic configuration of Ni ²⁺ is 3d^8 . Since CN ⁻ is a strong field ligand, it causes pairing of electrons, resulting in dsp^2 hybridization. All electrons are paired, making it diamagnetic. For [ Fe(CN) ₆]³⁻ , the oxidation state of Fe is +3 . The electronic configuration of Fe ³⁺ is 3d^5 . CN ⁻ is a strong field ligand, so the configuration is t_ 2g ^5 e_g^0 . It has one unpaired electron, making it paramagnetic. For [ Cu(H ₂ O) ₆]²⁺ , the oxidation s