Question

calculate the number of unpaired electrons in [Fe(CN)6]3-​

Answer 1

[Fe(CN)6] 3- according to valence bond theory can be drawn according to the attached picture.

Let us assume charge of Fe be 'x'.

x -6 = -3

x = +3

So, we need to remove 2 electrons from 4s and one from 3d.

Since, CN is a strong lig and, the unpaired electrons present in the 3d orbital pairs with itself.

Thus, we get number of unpaired electrons as 1