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 $=(3 e )$
$Y :\left[ Co ( NCS )_{4}\right]$
$Co ( II )$ is dsp $^{2}$
paramagnetic $=(1 e )$