Determine the number of unpaired electrons expected for [Fe (NO2) 6]3-and for [FeF6]3 - in terms of crystal field theory.

A. One unpaired electron

B. 5 unpaired electrons

Explanation:

In A, Fe is in + 3 oxidation state and Electronic configuration - [Ar]3d5

And NO2 is a strong field ligand hence it causes pairing in t2g orbitals and results one unpaired electron in dZX orbital.

In B, also Fe is in + 3 oxidation state but F is weak field ligand hence causes no pairing of Electrons hence it results 5 unpaired electrons with electronic configuration t2g^3 eg^2