Which kind of isomerism is exhibited by the octahedral complex, `[Co(NH_3)_4Br_2]Cl` ?

Options

A. Geometrical and inoization
B. Geometrical and optical
C. Optical and ionization
D. Only geometrical

Answer

To determine the type of isomerism exhibited by the octahedral complex \([Co(NH_3)_4Br_2]Cl\), we can follow these steps:

### Step 1: Identify the Structure of the Complex
The complex \([Co(NH_3)_4Br_2]Cl\) is an octahedral coordination complex. In this structure, cobalt (Co) is the central metal ion, surrounded by four ammonia (NH₃) ligands and two bromide (Br) ligands.

**Hint:** Remember that the geometry of the complex can influence the types of isomerism it can exhibit.

### Step 2: Determine Possible Isomerism Types
1. **Geometrical Isomerism**: This occurs due to the different arrangements of ligands around the central metal ion. In octahedral complexes, geometrical isomers can be cis (similar ligands adjacent to each other) or trans (similar ligands opposite each other).

2. **Ionization Isomerism**: This occurs when the complex can produce different ions in solution. For example, the complex can dissociate into \([Co(NH_3)_4Br_2]^+\) and \(Cl^-\) or \([Co(NH_3)_4BrCl]^+\) and \(Br^-\).

3. **Optical Isomerism**: This occurs when a complex can exist in two non-superimposable mirror images (enantiomers). For octahedral complexes with certain arrangements, optical isomerism can occur.

**Hint:** Consider how the ligands are arranged in the octahedral complex to identify geometrical isomers.

### Step 3: Analyze the Complex for Isomerism
- **Geometrical Isomerism**: The complex can have both cis and trans forms. For example:
- **Cis Isomer**: Both bromide ligands are adjacent to each other.
- **Trans Isomer**: The bromide ligands are opposite each other.

- **Ionization Isomerism**: The complex can dissociate in solution, leading to different ionization products.

**Hint:** Think about how the ligands can be rearranged or exchanged when the complex is dissolved in water.

### Step 4: Conclusion
Based on the analysis:
- The complex \([Co(NH_3)_4Br_2]Cl\) exhibits both geometrical isomerism (due to the arrangement of ligands) and ionization isomerism (due to the potential for different ions to form in solution).

Thus, the correct answer is that the complex exhibits **geometrical and ionization isomerism**.

**Final Answer:** The complex \([Co(NH_3)_4Br_2]Cl\) exhibits geometrical and ionization isomerism.