Identify the complex which exhibits all 3 characteristics; paramagnetic; high spin configuration; octahedral geometry

Step-by-step solution

In option (A), the complex is [ Co(NH ₃)₅ Cl ] Cl ₂ . The central metal ion is Co ³⁺ , which has a 3d^6 configuration. Since NH ₃ acts as a strong field ligand for Co ³⁺ , it causes pairing of electrons, resulting in a low spin, diamagnetic, and octahedral complex. In option (B), the complex is [ Ni(CO) ₄] . The central metal is Ni in the 0 oxidation state, with a 3d¹⁰ configuration. It forms an sp^3 hybridized, tetrahedral, and diamagnetic complex. In option (C), the complex is [ Ni(H ₂ O )₂( C ₂ O ₄)₂]²⁻ . The ce