Read the paragraph carefully and answer the questions given below it,
Stereo//space isomerism in coordination compounds
Gcometrical isomerism: Exhibited by square planer and octahedral complexes (not by tetrahedral complexes because relative positions are similar). If opposite positions have similar groups, it is trans, otherwise it is cis,
Optical isomerism: Shown when mirror image is non-superimposable. Cis-isomer shows but trans isomer does not
QWhich of the following types of square planar complexes can show geometrical isomerism (where M = metal and a, b = achiral ligands)

Answer

To solve the question regarding which types of square planar complexes can show geometrical isomerism, we will analyze each option provided in the question step by step.

### Step 1: Understand the types of square planar complexes
Square planar complexes can exhibit geometrical isomerism when there are different ligands attached to the central metal atom. The types of complexes we need to consider are:

1. **MA4**: Four identical ligands.
2. **MA3B**: Three identical ligands and one different ligand.
3. **MA2B2**: Two identical ligands and two different ligands.

### Step 2: Analyze each option for geometrical isomerism

**Option A: MA4**
- In this complex, all four ligands are identical (A, A, A, A).
- Since there are no different ligands, there cannot be any geometrical isomerism.
- **Conclusion**: MA4 does not show geometrical isomerism.

**Option B: MA3B**
- In this complex, there are three identical ligands (A) and one different ligand (B).
- The arrangement of ligands will result in a configuration where the identical ligands are indistinguishable from each other.
- Interchanging the positions of A and B will not create a new isomer because the angles between the ligands remain the same.
- **Conclusion**: MA3B does not show geometrical isomerism.

**Option C: MA2B2**
- In this complex, there are two identical ligands (A) and two identical ligands (B).
- The arrangement allows for two different configurations: one where the A ligands are adjacent (cis) and one where they are opposite each other (trans).
- This configuration allows for geometrical isomerism to occur.
- **Conclusion**: MA2B2 shows geometrical isomerism.

### Final Answer
The type of square planar complex that can show geometrical isomerism is **MA2B2**.

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