Question

$\left[ Co{{\left( N{{H}_{3}} \right)}_{5}}S{{O}_{4}} \right]Br\text{ and }\left[ Co{{\left( N{{H}_{3}} \right)}_{5}}Br \right]S{{O}_{4}}$ show which type of isomerism?
[A] Coordination
[B] Ionization
[C] Linkage
[D] None of these

Answer 1

HINT: In the given compound we have to determine the structural isomerism exhibited by it. Here, the ligand outside the coordination sphere can replace one of the similar ligands in the coordination sphere. Use this to find the solution.

COMPLETE STEP BY STEP SOLUTION: To answer this, let us discuss the types of isomerism mentioned in the options and then we can try to identify the correct answer. Firstly, we have coordination isomerism.
Coordination isomerism – When salts are produced by cationic and anionic compounds, metal centres between the complex entities can be interchanged to give coordination isomers. For example, ${{\left[ Pt{{\left( N{{H}_{3}} \right)}_{4}} \right]}^{2-}},{{\left[ PdC{{l}_{4}} \right]}^{2-}}$ can be inter-converted into ${{\left[ Pd{{\left( N{{H}_{3}} \right)}_{4}} \right]}^{2-}},{{\left[ PtC{{l}_{4}} \right]}^{2-}}$
Then, we have ionization isomerism.
Ionisation isomerism – This isomerism occurs due to interchange of ions between the inner and the outer coordination sphere. For example - $\left[ Co{{\left( N{{H}_{3}} \right)}_{5}}Br \right]S{{O}_{4}}\text{ and }\left[ Co{{\left( N{{H}_{3}} \right)}_{5}}S{{O}_{4}} \right]Br$
And lastly, we have linkage isomerism.
Linkage isomerism – This occurs due to the presence of ambidentate ligands having different donor sites. Example- $Co{{\left( SCN \right)}_{4}}^{2-}\text{ and }Co{{\left( NCS \right)}_{4}}^{2-}$
-We can understand from the above discussion that there exists ionization isomerism between $\left[ Co{{\left( N{{H}_{3}} \right)}_{5}}S{{O}_{4}} \right]Br\text{ and }\left[ Co{{\left( N{{H}_{3}} \right)}_{5}}Br \right]S{{O}_{4}}$.

Therefore, the correct answer is option [B] Ionization

NOTE: Isomerism is the phenomenon where two or more chemical compounds have the same chemical formula but different chemical structures. We can divide isomerism into two types namely structural isomerism and stereoisomerism.VThe isomerisms that we discussed above are all structural isomerisms. There are two more structural isomerisms that exist other than the three that we discussed above. They are hydration and ligand isomerism. Besides the structural isomers, there exist stereoisomers too. They are geometrical stereoisomers and optical stereoisomers.