Which of the following species is aromatic

Options

A.
B.
C.
D.

Explanation

To determine which of the given species is aromatic, we will follow the criteria for aromaticity. Aromatic compounds must satisfy the following conditions:

1. **Cyclic Structure**: The molecule must be cyclic.
2. **Planarity**: The molecule must be planar, allowing for p-orbitals to overlap.
3. **Complete Conjugation**: There must be a continuous overlap of p-orbitals around the ring.
4. **Hückel's Rule**: The molecule must have (4n + 2) π electrons, where n is a non-negative integer (0, 1, 2, ...).

Now, let’s analyze the options step by step:

### Step 1: Identify the structure of each species
- Check if the species is cyclic and planar.

### Step 2: Count the π electrons
- Count the number of π electrons in the cyclic structure.

### Step 3: Apply Hückel's Rule
- Determine if the number of π electrons fits the (4n + 2) rule.

### Step 4: Conclusion
- If the species meets all the above criteria, it is aromatic.

### Example Analysis:
1. **Species A**: If it has 4 π electrons and is cyclic, it does not satisfy Hückel's rule (4n + 2) because 4 is not in the form of (4n + 2).
2. **Species B**: If it has 6 π electrons, it satisfies Hückel's rule (4n + 2) where n=1. Therefore, it is aromatic.
3. **Species C**: If it has 8 π electrons, it does not satisfy Hückel's rule (4n + 2) because 8 is not in the form of (4n + 2).
4. **Species D**: If it has 2 π electrons, it satisfies Hückel's rule (4n + 2) where n=0. Therefore, it is aromatic.

### Final Answer:
Based on the analysis, the species that is aromatic is **Species B** (assuming it has 6 π electrons).

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