Which of the following complex does not show geometrical isomerism

Options

A. `[Co(NH_(3))_(4)Cl_(2)]^(+)`
B. `[Fe(NH_(3))_(2)(CN)_(4)]^(-)`
C. `[Cr(O x)_(3)]^(3-)`
D. `[Co(NH_(3))_(3)(NO_(2))_(3)]`

Explanation

To determine which complex does not show geometrical isomerism, we need to analyze the types of ligands and their arrangements around the central metal atom in the given complexes. Geometrical isomerism typically occurs in coordination complexes with a coordination number of 4 or 6, where ligands can be arranged in different spatial orientations.

### Step-by-Step Solution:

1. **Identify the Coordination Number**:
- Check the coordination number of each complex. Complexes with coordination numbers of 4 or 6 are more likely to exhibit geometrical isomerism.

2. **Analyze Each Complex**:
- **Complex 1**: Cobalt(III) complex with ligands like NH3 and Cl.
- Coordination number = 6 (Cobalt can form octahedral complexes).
- Possible geometrical isomers: Yes (cis and trans forms).

- **Complex 2**: A complex with ligands like NH3 and CN.
- Coordination number = 6.
- Possible geometrical isomers: Yes (cis and trans forms).

- **Complex 3**: A square planar complex with ligands like Cl and NH3.
- Coordination number = 4.
- Possible geometrical isomers: Yes (cis and trans forms).

- **Complex 4**: A complex with all identical ligands (e.g., all NH3 or all Cl).
- Coordination number = 6 or 4.
- Possible geometrical isomers: No (only one arrangement possible).

3. **Conclusion**:
- The complex that does not show geometrical isomerism is the one with all identical ligands, as there is no variation in the arrangement of ligands around the central metal atom.

### Final Answer:
The complex that does not show geometrical isomerism is the one with all identical ligands.

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