Question

What is the CFSE of the compound $[Fe{F}_6{]}^{4-}$ in terms of Dq?

Answer 1

In $[Fe{F}_6{]}^{4-},F^{-}$ is a weak field ligand and Fe is in $2+$ state.

$\therefore F{e}^{2+}:$

$\Rightarrow$ CFSE = $-0.4\times \left(4\right)+0.6\times 2{\Delta }_o$

= $-1.6+1.2{\Delta }_o$

= $-0.4{\Delta }_o$

$\Rightarrow$ magnitude of CFSE is $0.4{\Delta }_o$

Since ${\Delta }_o=10Dq$

$\therefore CFSE=0.4\times 10Dq$

= 4 Dq