Question

You are given the following two complexes $X$ and $Y$ which are isomers of each other $X$ is $Hg\left[Co(SCN{)}_4\right]$. It is further given that paramagnetic moment of $X$ is found to be more than $Y$. Then which of the following is correct.

• A. Anion of $X$ will be tetrahedral and that of $Y$ will be square planar.
• B. Anion of $X$ will be square planar but that of $Y$ will be tetrahedral
• C. Both the anions will be tetrahedral
• D. Both the anions will be square planar

Answer 1

Answer: (A)

$X:Hg\left[Co(SCN{)}_4\right]$
$Co(II)$ is sp ${}^3$
paramagnetic $=(3e)$
$Y:\left[Co(NCS{)}_4\right]$
$Co(II)$ is dsp ${}^2$
paramagnetic $=(1e)$