Crystal Field Theory

- [Mn(CN)_6]^{4-} (A) has a configuration, which corresponds to due to the strong field ligand CN⁻ causing pairing of electrons in the lower orbital. This matches with configuration (R). - [Co(H_2O)_6]^{2+} (B) has a configuration, leading to a weak field interaction with water molecules as ligands, resulting in configuration (S), which is . - [Fe(H_2O)_6]^{2+} (C) has a configuration, which leads to a relatively weaker splitting of the orbitals, with electrons occupying . This corresponds to configuration (P). - [MnCl_4]^{2-} (D) has a configuration, which corresponds to (Q) , consistent with a low-spin case.