Question:

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

t2g4eg2

t2g6eg0

e3t23

e4t22

Correct option is t2g6eg0.
K4[Fe(CN)6]
Fe ground state [Ar]3d64s2
Fe2+: 3d64s0
So, t2g6eg0 is the correct option.