Question

$C{{O}_{2}}$ is isostructural with _______
(a) $SnC{{l}_{2}}$
(b) $HgC{{l}_{2}}$
(c) $SC{{l}_{2}}$
(d) $Zn{{I}_{2}}$

Answer 1

Isostructural compounds are compounds with similar chemical structures. Isoelectronic compounds are isostructural. Carbon dioxide has a linear structure.

Complete step by step solution :
Carbon dioxide is a covalent compound having 3 atoms. One carbon atom and two oxygen atoms. These are arranged linearly. The two oxygen atoms are present on either side of the carbon and are doubly bonded to the carbon atom. This gives carbon dioxide a linear structure. The bond angle of$O=C=O$ is ${{180}^{o}}$.
In case of $HgC{{l}_{2}}$ , it is also linear molecule with the $Cl-Hg-Cl$ bond angle being ${{180}^{o}}$.
Other molecules mentioned in the question are non-linear molecules.
Hence, the carbon dioxide is isostructural with $HgC{{l}_{2}}$.

The correct answer to the question is option (b).

Additional Information:
-The hybridisation of a compound determines its geometry. Isostructural species have the same shape and hybridisation.
-The bond order of carbon dioxide is two. Each double bond of carbon dioxide has a sigma bond and a pi bond. $HgC{{l}_{2}}$ is an orthogonal crystal structure with linear geometry. The bond between mercury and chloride ions is sigma bonds. There are no lone pairs on mercury.
-Most minerals are isostructural. They only differ like their cations.
-There are isostructural series, or isostructural polymorphs or isostructural phase. transitions.

Note : We should keep in mind that the structure of the molecules that are compared should be similar. Then only it becomes isostructural compounds. We also assume that species having the same hybridisation are isostructural. But it is not right, their shape might be different so they would not be isostructural species.