Question

Cr(NH3)6]Cl3 why cant show ionisation isomerism

Answer 1

The complex $\text{[Cr(NH}_3)_6]\text{Cl}_3$ cannot show ionization isomerism because all the ligands ($\text{NH}_3$) are neutral molecules. Ionization isomerism requires the interchange of an ionic ligand inside the coordination sphere with an ionic counter ion outside the coordination sphere, which is not possible here as there are no ionic ligands to exchange with the $\text{Cl}^-$ counter ions.

Answer 2

Explanation:

Ionization isomerism occurs when a complex compound has the same overall molecular formula but produces different ions in solution. This type of isomerism arises from the interchange of an ionic ligand within the coordination sphere with an ionic counter ion outside the coordination sphere.

In the complex $\text{[Cr(NH}_3)_6]\text{Cl}_3$:

1. Ligands: All six ligands are ammonia ($\text{NH}_3$) molecules. Ammonia is a neutral ligand.
2. Counter ions: The three chloride ($\text{Cl}^-$) ions are outside the coordination sphere, acting as counter ions.

For ionization isomerism to occur, one of the $\text{Cl}^-$ ions would need to enter the coordination sphere, and in exchange, one of the ligands inside the coordination sphere would need to move out to become a counter ion.

However, since all the ligands ($\text{NH}_3$) are neutral molecules, they cannot act as counter ions. If a $\text{Cl}^-$ ion were to enter the coordination sphere, an $\text{NH}_3$ molecule would have to leave. The $\text{NH}_3$ molecule that leaves would remain a neutral molecule and would not contribute to the different ions produced in solution, which is a defining characteristic of ionization isomers. Ionization isomers must yield different ionic species in solution.

Therefore, because there is no ionic ligand inside the coordination sphere that can be exchanged with the anionic counter ions ($\text{Cl}^-$), $\text{[Cr(NH}_3)_6]\text{Cl}_3$ cannot show ionization isomerism.