. Which of the following does not show geometrical isomerism?

Options

A. `[Ni(CÓ)_(4)]`
B. `[Pt(NH_(3)]_(2)CI_(2)]`
C. `[Co(NH_(3))_(4)CI_(2)]^(+)`
D. `[Co(NH_(3))_(3)CI_(3)]`

Answer

To determine which of the given compounds does not show geometrical isomerism, we need to analyze each option based on the criteria for geometrical isomerism in coordination compounds.

### Step-by-Step Solution:

1. **Understanding Geometrical Isomerism**:
- Geometrical isomerism occurs in coordination compounds when there are different arrangements of ligands around the central metal atom.
- For geometrical isomerism to be possible, there must be at least two different types of ligands, and at least one of those ligands must be present in a quantity of two or more.

2. **Analyzing Each Option**:
- **Option 1: Ni(CO)₄**
- This compound has only one type of ligand (CO).
- Since there are no different types of ligands, it cannot exhibit geometrical isomerism.

- **Option 2: Pt(NH₃)₂Cl₂**
- This compound has two types of ligands: NH₃ and Cl.
- There are two NH₃ and two Cl ligands, which allows for the possibility of geometrical isomers (cis and trans forms).

- **Option 3: Co(NH₃)₂Cl₂**
- Similar to option 2, this compound has two types of ligands: NH₃ and Cl.
- It can also show geometrical isomerism (cis and trans forms).

- **Option 4: Co(NH₃)₃Cl₃**
- This compound has two types of ligands: NH₃ and Cl.
- It can exhibit geometrical isomerism as well, due to the presence of multiple ligands.

3. **Conclusion**:
- Based on the analysis, **Option 1: Ni(CO)₄** does not show geometrical isomerism because it contains only one type of ligand.

### Final Answer:
**The compound that does not show geometrical isomerism is Option 1: Ni(CO)₄.**