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Question:

The crystal field stabilization energy (CFSE) of [Fe(H₂O)₆]Cl₂ and K₂[NiCl₄], respectively, are:

−2.4Δo and −1.2Δt

−0.6Δo and −0.8Δt

−0.4Δo and −0.8Δt

−0.4Δo and −1.2Δt

Solution:

The correct option is A −0.4Δo and −0.8Δt
a) [Fe(H₂O)₆]Cl₂, Fe²⁺ → 3d⁶ → (t₂g)⁴(eg)²
CFSE = [4(-0.4Δo) + 2(0.6Δo)] = -0.4Δo
b) K₂[NiCl₄], Ni²⁺ → 3d⁸ → (eg)⁴(t₂g)⁴ (tetrahedral)
CFSE = [4(-0.6Δt) + 4(0.4Δt)] = -0.8Δt