Explain different types of structural isomerism in coordination compounds.

(N/A) $(i)$ Ionisation isomerism: This form of isomerism arises when the counter ion in a complex salt is itself a potential ligand and can displace a ligand which can then become a counter ion. Hence,there is an exchange of ligands between the coordination entity and the ionisation sphere.
The compounds showing ionisation isomerism give different ions in aqueous solution.
For example: $[Co(NH_{3})_{5}(SO_{4})]Br$ and $[Co(NH_{3})_{5}Br]SO_{4}$.
$(ii)$ Hydrate isomerism (Solvate isomerism): This form of isomerism exists where water is involved as a solvent. When water molecules are interchanged between the coordination sphere and the ionisation sphere,the resulting isomers are called hydrate (solvate) isomers.
For example:
$[Cr(H_{2}O)_{6}]Cl_{3} \Rightarrow \text{Violet}$
$[Cr(H_{2}O)_{5}Cl]Cl_{2} \cdot H_{2}O \Rightarrow \text{Grey-green}$
$[Cr(H_{2}O)_{4}Cl_{2}]Cl \cdot 2H_{2}O \Rightarrow \text{Green}$
$(iii)$ Linkage isomerism: This isomerism arises in a coordination compound containing an ambidentate ligand. $A$ simple example is provided by complexes containing the thiocyanate ligand $(NCS^{-})$ which may bind either through sulphur or by nitrogen.
For example:
$(a) [Cr(SCN)(H_{2}O)_{5}]^{2+}$ and $[Cr(NCS)(H_{2}O)_{5}]^{2+}$
$(b) [Co(ONO)(NH_{3})_{5}]^{2+}$ and $[Co(NO_{2})(NH_{3})_{5}]^{2+}$
Jorgensen discovered such behaviour in the complex $[Co(NH_{3})_{5}(NO_{2})]Cl_{2}$,which is obtained in a red form,in which the nitrite ligand is bound through oxygen $(-ONO)$,and as a yellow form,in which the nitrite ligand is bound through nitrogen $(-NO_{2})$.
$(iv)$ Coordination isomerism: This type of isomerism arises from the interchange of ligands between cationic and anionic entities of different metal ions present in a complex.
For example:
$(a) [Co(NH_{3})_{6}][Cr(CN)_{6}]$ and $[Cr(NH_{3})_{6}][Co(CN)_{6}]$
$(b) [Cu(NH_{3})_{4}][PtCl_{4}]$ and $[Pt(NH_{3})_{4}][CuCl_{4}]$