Question

Which type of isomers are $[Pt{(N{H_3})_4}C{l_2}]B{r_2}$ and $[Pt{(N{H_3})_4}B{r_2}]C{l_2}$ ?

Answer 1

The compounds which have the same molecular formula but have different structures and chemical properties are called structural isomers. There are few types of structural isomers which include linkage isomers, ionization isomers, coordinate isomers, Solvate isomers. We will now see which type of above mentioned isomerism is exhibited by the given two compounds.

Complete answer:
The types of structural isomerisms are:-
Ionisation isomerism- In this type of isomerism the counter or ionisable ion has the ability to replace the ligand in entity or coordination sphere.
Linkage isomerism- This type of isomerism arises when an ambidentate ligand (the ligand which has two or more donor sites and can bind through a central metal atom through any one of them) is present. In this isomerism, there is a difference in the linkage of a ligand (ambidentate).
Coordination Isomerism- This isomerism exists when the ligands in anionic and cationic species get interchanged.
Solvate Isomerism- In this water molecule is present either as ligand or free molecule with compound.
Let compound $(1)$ is $[Pt{(N{H_3})_4}C{l_2}]B{r_2}$ and compound $(2)$ is $[Pt{(N{H_3})_4}B{r_2}]C{l_2}$.
In both the given compounds, the central metal atom is attached to six ligands which means it has Coordination number - $6$ and hence, both the compounds will have the same geometry which is octahedral geometry.
We can clearly see that the two counter ions or ionisable ions $(B{r^ - })$ in compound $(1)$ have replaced the two ligands $(C{l^ - })$ in the compound $(2)$ . Here, the counterion is the prospective ion itself and has replaced the ligand present in the entity itself.
So, we can conclude from above mentioned definitions of different structural isomerisms that the above given compounds are structural isomers and possess ionization isomerism.

Note:
Coordination entity is the complex formed when a central metal atom is surrounded by ligands or ions. Ligands are defined as the ions or groups which surround the central metal atom and donate their lone pair of electrons in the valence empty orbitals of the metal atom. Ligands can be ions or molecules.