Question

The CFSE value of tetrahedral $[CoC{l}_4{]}^{2-}$ complex is:

• A. $+1.2{\Delta }_t$
• B. $-1.2{\Delta }_t$
• C. $-1.8{\Delta }_t$
• D. $+2.4{\Delta }_t$

Answer 1

The correct option is B $-1.2{\Delta }_t$

In $[CoC{l}_4{]}^{2-}$, the oxidation state of metal complex is +2.
Thus, its configuration is $d^7$.
$C{l}^{-}$ is a weak field ligand so it will give high spin complex.


$\text{CFSE}=4\times (-0.6){\Delta }_t+3\times (+0.4){\Delta }_t$

$\text{CFSE}=-2.4{\Delta }_t+1.2{\Delta }_t$
$\text{CFSE}=-1.2{\Delta }_t$