Question

The value for crystal field stabilisation energy is zero for:

• A. $K_2\left(Mn{F}_6\right]$
• B. $K_3\left[Fe\right(CN{)}_6]$
• C. $K_3\left[Fe{F}_6\right]$
• D. $K_4\left[Fe\right(CN{)}_6]$

Answer 1

Answer: (C)

$K_3\left[Fe{F}_6\right]$

Solution:- (C) $K_3\left[Fe{F}_6\right]$

The CFSE for tetrahedral complex is given by-

$CFSE=-0.4t_{2_g}{e}^{-}+0.6e_g{e}^{-}$

For $K_3\left[Fe{F}_6\right]$-

$\Rightarrow {Fe}^{+3}={t_{2_g}}^3{e_g}^2$

$CFSE=-0.4\times 3+0.6\times 2=0$