Amongst the ions the aromatic specles are :

Options

A.
B.
C.
D.

Answer

To determine which of the given ions are aromatic species, we need to apply the four criteria that define aromaticity. Here’s a step-by-step solution:

### Step 1: Identify the Criteria for Aromaticity
For a compound to be classified as aromatic, it must satisfy the following four conditions:
1. **Cyclic Structure**: The molecule must be in a ring form.
2. **Planarity**: The molecule must be flat, allowing for overlapping p-orbitals.
3. **Conjugation**: There must be a continuous overlap of p-orbitals, which typically means alternating single and double bonds.
4. **Hückel's Rule**: The molecule must have \(4n + 2\) π electrons, where \(n\) is a non-negative integer (0, 1, 2, ...).

### Step 2: Analyze Each Ion
Let’s analyze each of the ions provided in the question based on the criteria:

- **Ion A**:
- Number of π electrons: 4
- Cyclic: Yes
- Planar: Yes
- Conjugation: Yes
- **Conclusion**: Fails Hückel's rule (4n π electrons). Thus, it is **anti-aromatic**.

- **Ion B**:
- Number of π electrons: 6
- Cyclic: Yes
- Planar: Yes
- Conjugation: Yes
- **Conclusion**: Satisfies Hückel's rule (4n + 2 where n=1). Thus, it is **aromatic**.

- **Ion C**:
- Number of π electrons: 6
- Cyclic: Yes
- Planar: Yes
- Conjugation: Yes
- **Conclusion**: Satisfies Hückel's rule (4n + 2 where n=1). Thus, it is **aromatic**.

- **Ion D**:
- Number of π electrons: 8
- Cyclic: Yes
- Planar: No (non-planar structure)
- Conjugation: Yes
- **Conclusion**: Fails planarity and Hückel's rule (4n π electrons). Thus, it is **non-aromatic**.

### Step 3: Final Conclusion
Based on the analysis:
- **Aromatic Ions**: Ion B and Ion C
- **Non-aromatic Ion**: Ion D
- **Anti-aromatic Ion**: Ion A

Thus, the aromatic species among the ions are **Ion B and Ion C**.