Explain why [Fe(H2O)6]3+ has magnetic moment value of 5.92 BM whereas

[Fe(CN)6]3– has a value of only 1.74 BM.

[Fe(CN)₆]^3–

Fe³⁺ has six unpaired electrons. CN^- is a strong field ligand which will cause pairing of all the electrons. So, the electrons will start pairing leaving behind one unpaired electron. So, the magnetic moment will be = = 1.74 BM

For [Fe(H₂O)₆]³⁺, H₂O being a weak field ligand won’t cause pairing of electrons. So, the number of unpaired electrons will be 5. The magnetic moment will be = 5.92 BM