Which of the following types of square planar complexes can't show geometric isomerism ?

Options

A. `MA_(4)`
B. `MA_(3)B`
C. `MAB_(3)`
D. All of these

Explanation

To determine which types of square planar complexes cannot show geometric isomerism, we need to analyze the different configurations of the complexes based on their ligand arrangements.

### Step-by-Step Solution:

1. **Understanding Square Planar Complexes**:
- Square planar complexes typically have a central metal atom surrounded by four ligands arranged at the corners of a square.

2. **Types of Ligand Arrangements**:
- The two main types of ligand arrangements in square planar complexes are:
- **MA4**: Four identical ligands.
- **MA3B**: Three identical ligands and one different ligand.

3. **Analyzing MA4 Complex**:
- In a complex of the type MA4, all four ligands are identical.
- Since all ligands are the same, any rearrangement of these ligands does not lead to a different geometry.
- Therefore, MA4 complexes cannot show geometric isomerism.

4. **Analyzing MA3B Complex**:
- In a complex of the type MA3B, there are three identical ligands (A) and one different ligand (B).
- The arrangement can be visualized as:
```
A
A M B
A
```
- In this arrangement, regardless of how you rotate or rearrange the ligands, the position of the B ligand will always be opposite to one of the A ligands.
- Thus, there are no distinct cis or trans forms, and this complex also cannot show geometric isomerism.

5. **Analyzing MA2B2 Complex**:
- In a complex of the type MA2B2, there are two identical ligands A and two identical ligands B.
- This arrangement can lead to two distinct configurations (cis and trans), where the two A ligands can be adjacent (cis) or opposite each other (trans).
- Therefore, MA2B2 complexes can show geometric isomerism.

6. **Conclusion**:
- Based on the analysis, the types of square planar complexes that cannot show geometric isomerism are:
- **MA4** (four identical ligands)
- **MA3B** (three identical ligands and one different ligand)

### Final Answer:
The types of square planar complexes that cannot show geometric isomerism are **MA4** and **MA3B**.