Question

Which one of the following is a type of structural isomer $?$
(i) Coordination Isomerism
(ii) Linkage Isomerism
(iii) Ionisation Isomerism
(iv) All of the above

Answer 1

Two or more compounds with the same formula but different arrangements of the ligands are called isomers. Taking the metal ion to be constant, consider what are the possible ways you can arrange the ligands present in the molecule so that the formula remains the same but the structure or bonding is different.

Complete step by step solution:
Isomers are compounds that have the same formula but they differ in the arrangement of the ligands. Structural isomers are those which contain the same number of atoms of each kind but differ in the bonding of the atoms. Structural isomers can be of three different types:
$\left( a \right)$ Linkage Isomerism: Linkage isomerism occurs with ambidentate ligands in which the atoms of the molecular ligands that bind to the central metal ion are different. The best known example of ambidentate ligand is $N{O_2}^ -$ and $ON{O^ - }$ . In case of $N{O_2}^ -$ the ligand gets attached to the metal centre via $N$ while in case of $ON{O^ - }$ the bonding is through $O$ atom.
$\left( b \right)$ Ionisation Isomerism: Ionisation isomerism occur when a ligand that is bound to the metal centre exchanges its place with an anion or neutral molecule that was originally outside the coordination complex $($ provided the geometry of the central metal ion and the identity of other ligands are identical $)$ leading to the formation of different ions during the process of ionization. For example: $\left[ {Co{{\left( {N{H_3}} \right)}_5}Cl} \right]Br$ and $\left[ {Co{{\left( {N{H_3}} \right)}_5}Br} \right]Cl$ are ionisation isomers.
$\left( c \right)$ Coordination Isomerism: Coordination isomerism occurs when the composition of the coordination complex ion varies. The total ratio of ligand to metal remains the same, but the ligands attached to a specific metal ion changes. For example: $\left[ {Zn{{\left( {N{H_3}} \right)}_4}} \right]\left[ {Cu{{\left( {Cl} \right)}_4}} \right]$ and $\left[ {Cu{{\left( {N{H_3}} \right)}_4}} \right]\left[ {Zn{{\left( {Cl} \right)}_4}} \right]$ are coordination isomers.
So all the given options are correct.
Hence the correct answer is (iv) All of the above.

Note:
Make sure to read the question properly and understand what the question is asking for. The options should also be read with proper attention in order to avoid unnecessary errors. Do not get confused between the two different types of isomers: structural isomerism and stereoisomerism.