Which of the following is aromatic in nature?

Options

A.
B.
C.
D.

Answer

To determine which of the given compounds is aromatic in nature, we need to follow a systematic approach based on the criteria for aromaticity. Here’s a step-by-step solution:

### Step 1: Understand the Criteria for Aromaticity
A compound must meet the following criteria to be considered aromatic:
1. **Cyclic Structure**: The compound must be cyclic.
2. **Planarity**: The compound must be planar (flat).
3. **Conjugation**: There must be a continuous overlap of p-orbitals (conjugation).
4. **Hückel's Rule**: The compound must have \(4n + 2\) π electrons, where \(n\) is a non-negative integer (0, 1, 2, ...).

### Step 2: Analyze Each Compound
Now, we will analyze each compound based on the criteria mentioned above.

#### Compound A:
- **Cyclic**: Yes
- **Planar**: No (tub-like structure)
- **Conjugation**: Not applicable due to lack of planarity.
- **Conclusion**: Not aromatic.

#### Compound B:
- **Cyclic**: Yes
- **Planar**: Yes
- **Conjugation**: Yes (lone pairs and π bonds are involved in conjugation)
- **π Electrons**: 4 (2 from π bonds and 2 from lone pairs)
- **Hückel's Rule**: Does not satisfy \(4n + 2\) (since 4 is \(4n\) for \(n=1\)).
- **Conclusion**: Anti-aromatic (not aromatic).

#### Compound C:
- **Cyclic**: Yes
- **Planar**: Yes
- **Conjugation**: Yes (continuous overlap of p-orbitals)
- **π Electrons**: 2 (only from π bonds)
- **Hückel's Rule**: Satisfies \(4n + 2\) (for \(n=0\), 2 π electrons).
- **Conclusion**: Aromatic.

#### Compound D:
- **Cyclic**: Yes
- **Planar**: No (not flat)
- **Conjugation**: Not applicable due to lack of planarity.
- **Conclusion**: Not aromatic.

### Step 3: Final Conclusion
Based on the analysis, **Compound C** is the only aromatic compound among the options provided.