Spin-only magnetic moment of an octahedral complex of Fe2+ in the pres...
Spin-only magnetic moment of an octahedral complex of Fe2+ in the pres...
Understanding the Spin-Only Magnetic Moment
The spin-only magnetic moment is an important concept in coordination chemistry, particularly for transition metal complexes. It is calculated using the formula:
μ = √(n(n + 2)),
where n = number of unpaired electrons.
Fe2+ in an Octahedral Complex
- Iron (Fe) has an atomic number of 26, and in its +2 oxidation state, Fe2+ has the electronic configuration of [Ar] 3d^6.
- In an octahedral field, the 3d orbitals split into two sets: t2g (lower energy) and eg (higher energy).
Strong Field Ligands
- Strong field ligands, such as CN- or CO, cause a significant splitting of the d-orbitals and promote pairing of electrons.
- In the case of Fe2+ with a strong field ligand, the six d-electrons (3d^6) will fill the t2g orbitals first, resulting in:
- t2g: 6 electrons (3 pairs)
- eg: 0 electrons
This leads to no unpaired electrons.
Calculating the Spin-Only Magnetic Moment
- Since all the electrons are paired in the t2g orbitals, n (the number of unpaired electrons) is 0.
- Substituting n = 0 into the formula for magnetic moment:
μ = √(0(0 + 2)) = 0
Conclusion
Thus, the spin-only magnetic moment of the octahedral complex of Fe2+ in the presence of a strong field ligand is 0 B.M. Therefore, the correct answer is option 'B'.