Question

The type of isomerism shown by the complex [CoCl₂(en)₂] is

• A. Geometrical isomerism
• B. Ionization isomerism
• C. Coordination isomerism
• D. Linkage isomerism

Answer 1

The Correct Option is A

The question asks us to determine the type of isomerism shown by the complex \( [\mathrm{CoCl_2(en)_2}] \). We will identify the correct type of isomerism by analyzing the structure of this complex and considering how its components are arranged.

Step-by-step Explanation:

1. Understanding the Complex:
   • The complex given is \( [\mathrm{CoCl_2(en)_2}] \), where "en" stands for ethylenediamine, a bidentate ligand.
   • The cobalt metal center is coordinated with two chloride ions and two ethylenediamine ligands.
2. Types of Isomerism:
   • Geometrical Isomerism: This occurs when the ligand arrangement around the central metal can differ, leading to more than one distinct compound despite having the same connectivity. Commonly exhibited in square planar or octahedral complex ions.
   • Ionization Isomerism: This type occurs when different ions are formed by the exchange of ligands between the coordination sphere and outside of it.
   • Coordination Isomerism: It occurs in compounds where both cation and anion are complexes. The exchange of ligands between the cation and anion results in this type.
   • Linkage Isomerism: Occurs when a ligand can bind to the central atom in more than one way due to the presence of different donor atoms. Example: NO₂^- can bind through nitrogen or oxygen.
3. Analysis of Geometrical Isomerism:
   • For the complex \( [\mathrm{CoCl_2(en)_2}] \), the configuration around the cobalt is octahedral.
   • In the octahedral geometry, the ethylenediamine ligands will generally occupy adjacent positions or opposite positions creating a distinct difference with arrangement (cis and trans forms).
   • These different arrangements correspond to geometrical isomers.

Conclusion: The complex \( [\mathrm{CoCl_2(en)_2}] \) exhibits Geometrical isomerism due to the possibility of different spatial arrangements of its ligands around the central cobalt ion in an octahedral shape. Therefore, the correct answer is Geometrical isomerism.