What is the correct electronic configuration of the central atom in K4[Fe(CN)6] based on crystal field theory ?

Question : What is the correct electronic configuration of the central atom in K₄[Fe(CN)₆] based on crystal field theory ?

answer : from all above options the correct answer is option (2)  t⁶_2g e_g⁰

answer explanation : In the presence of a strong-field ligand CN^– etc., the electrons pair up because △₀ is large enough to overcome the energy required to pair up the electron in the same orbital, that is pairing energy (P). This results in filling of the lower energy t_2g d-orbitals. Thus, the electronic configuration of Fe²⁺ in complex K₄[Fe(CN)₆] t⁶_2g e_g⁰
that is why we have marked option (2) for correct answer so Answer (2)

in short we can say that –

If we see the central atom of compound K₄[Fe(CN)₆] then we will find that

Fe contains [Ar] 3d⁶ 4s² electronic configuration in ground state.

Now if see the electronic configuration of Fe²⁺ that will be 3d⁶4s⁰ , that is why we have marked option (2) for correct answer.

for more detail have a look at the figure given below –