Question

The CFSE for $[CoC{l}_6{]}^{4-}$ complex is 18000 $c{m}^{-1}$. The $\Delta$ for $[CoC{l}_4{]}^{2-}$ will be -

• A. $18000c{m}^{-1}$
• B. $16000c{m}^{-1}$
• C. $8000c{m}^{-1}$
• D. $2000c{m}^{-1}$

Answer 1

The correct option is C $8000c{m}^{-1}$

${\Delta }_O$and${\Delta }_T$ denotes CFSE value for octahedral complex and tetrahedral complex respectively.

Here, CFSE value of octahedral ${\left[CoC{l}_6\right]}^{4-}$ complex is given, we have to find out CFSE of tetrahedral complex ${\left[CoC{l}_4\right]}^{2-}$.

We know that,

${\Delta }_T=\frac{4}{9}\times {\Delta }_O{\Delta }_T=\frac{4}{9}\times 18000c{m}^{-1}=8000c{m}^{-1}$