Chemistry - Coordination Chemistry Question with Solution | TestHub

Ionization isomers have the same overall formula but differ in which ion is inside the coordination sphere and which is outside. In ionization isomerism, a ligand exchanges places with an ion outside the coordination sphere.

The given complex is $[\mathrm{Cr}({\mathrm{H}}_2\mathrm{O}{)}_4\mathrm{Cl}({\mathrm{NO}}_2)]\mathrm{Cl}$.

Here, ${\mathrm{Cl}}^{-}$ is the counter ion.

For an ionization isomer, the ${\mathrm{NO}}_2^{-}$ ligand inside the coordination sphere exchanges with the ${\mathrm{Cl}}^{-}$ counter ion.

So, the ${\mathrm{NO}}_2^{-}$ ion moves outside, and one ${\mathrm{Cl}}^{-}$ ion moves inside.

The resulting complex is $[\mathrm{Cr}({\mathrm{H}}_2\mathrm{O}{)}_4{\mathrm{Cl}}_2]({\mathrm{NO}}_2)$.

The correct answer is B.