Q. Which of the following complexes has minimum magnitude of Ape?
Delhi UMET/DPMTDelhi UMET/DPMT 2010
Solution:
[a] In $\left[ Cr ( CN )_{6}\right]^{3-}$ and $\left[ Cr \left( H _{2} O \right)_{6}\right]^{3+}$ both, $Cr$ is present as $Cr ^{3+}$.
$C F S E=-0.4 \times 3=-1.2$
[b]$ \ln \left[ CO \left( NH _{3}\right)_{6}\right]^{3+}, Co$ is present as $CO ^{3+}$
$C F S E=-0.4 \times 6=-2.4$
[c] $\ln \left[ COCl _{6}\right]^{3-}, CO$ is again present as $CO ^{2+}$
$C F S E=-0.4 \times 4+0.6 \times 2=-1.6+1.2=-0.4$
Thus, the magnitude of $\Delta_{o}$ is minimum for $\left[ COCl _{6}\right]^{3-}-$
