Which of the following compounds/complex ions would not show geometrical isomerism ?

Options

A. `[Co (en) (SCN)_4]^(-)`
B. `[Pt (en)_2 Cl Br]^(2+)`
C. `[Cr (gly)_3]`
D. `[Pt (gly)_2 Cl_2]`

Explanation

To determine which of the given compounds or complex ions would not show geometrical isomerism, we need to analyze each option based on the coordination number and the arrangement of ligands around the central metal atom.

### Step-by-Step Solution:

1. **Understand Geometrical Isomerism**:
- Geometrical isomerism occurs in coordination compounds where ligands can be arranged differently around the central metal atom. This is common in octahedral and square planar complexes.

2. **Analyze Each Option**:
- **Option 1: [Co(en)(SCN)₄]⁻**:
- This complex has a coordination number of 6 (4 SCN and 2 en). It can show geometrical isomerism as the SCN ligands can be arranged differently around the cobalt ion. However, it is a type of complex that typically does not exhibit geometrical isomerism due to its symmetrical nature.

- **Option 2: [Pt(en)₂ClBr]²⁺**:
- This complex has a coordination number of 4 and is square planar. It can show geometrical isomerism because the two different ligands (Cl and Br) can be arranged in two different ways (cis and trans).

- **Option 3: [Cr(Gl)y]³⁺**:
- This complex is ambiguous without specific ligand information. However, if it has a coordination number of 6, it could potentially show geometrical isomerism depending on the ligands.

- **Option 4: [Pt(Gl)₂Cl₂]**:
- This complex has a coordination number of 4 and is square planar. It can show geometrical isomerism (cis and trans) due to the two different types of ligands.

3. **Conclusion**:
- After analyzing the options, the first option [Co(en)(SCN)₄]⁻ is the correct answer as it does not exhibit geometrical isomerism due to its symmetrical arrangement and the nature of the ligands involved.

### Final Answer:
The compound that would not show geometrical isomerism is **Option 1: [Co(en)(SCN)₄]⁻**.