Q. Show Crystal Field Splitting in Square Planar Complexes?

In a d¹ or d² system the electrons will always go in the 'e' set of orbitals with the release of corresponding amount of energy (CFSE). For d¹ it will be -3/5Δ_t and for d² it will be 2(-3/5Δ_t) or -6/5Δ_t. These values can be converted in terms of & for comparison. Again for systems from d³ to d⁶ there are two different configurations possible in each case as shown in Fig.

From Table 14.5, you can see that the pairing energies (P) andΔ₀ for common ligands are of comparable order of magnitude. It is also true that Δ_t is almost one-half the value of Δ₀.  Hence we can say that pairing energy, P, is almost double the value of at or in other words P >>Δ₀. Under the circumstances all the electrons in any system in tetrahedral field will- spread out in e and t sets of orbitals rather than pair up in e-orbitals. To put it in other terms it is said that the low spin tetrahedral, complexes of the first row transition elements are not known.

Crystal Field Splitting in Square Planar Complexes