An octahedral complex of Fe ³⁺ exhibits a spin-only magnetic moment of 1.73 BM . Ignoring the pairing energy, the Crystal Field Stabilization Energy (CFSE) of this complex is:

Step-by-step solution

Fe has atomic number 26. Its electronic configuration is [ Ar ] 3d^6 4s^2 . For Fe ³⁺ , the electronic configuration is [ Ar ] 3d^5 . The spin-only magnetic moment is given as 1.73 BM . Using the formula = n(n+2) , we get n = 1 . Thus, there is 1 unpaired electron. For a d^5 octahedral complex to have 1 unpaired electron, it must be a low-spin complex with the configuration t_ 2g ^5 e_g^0 . The Crystal Field Stabilization Energy (CFSE) is calculated as: CFSE = [-0.4(n_ t_ 2g ) + 0.6(n_ e_g )] _o CFSE = [-0.4(5) + 0