Why is benzene extra ordinarily stable though it contains three double bonds?

Explanation

To understand why benzene is extraordinarily stable despite containing three double bonds, we can break down the explanation into several key points:

### Step 1: Structure of Benzene
Benzene is represented as a hexagonal ring consisting of six carbon atoms (C6) and six hydrogen atoms (H6). It has alternating single and double bonds, which can be depicted as:

```
C
/ \
H C
| |
C C
\ /
C
```

### Step 2: Aromatic Nature
Benzene is classified as an aromatic compound. For a compound to be aromatic, it must satisfy Huckel's rule, which states that a compound must have a certain number of π (pi) electrons. Specifically, it must have \(4n + 2\) π electrons, where \(n\) is a non-negative integer.

### Step 3: Application of Huckel's Rule
In benzene, there are a total of 6 π electrons (one from each carbon-carbon double bond). By setting \(n = 1\) in Huckel's rule:

\[ 4n + 2 = 4(1) + 2 = 6 \]

This confirms that benzene follows Huckel's rule, thus qualifying it as aromatic.

### Step 4: Planarity of Benzene
Benzene is a planar molecule. This planarity allows for effective overlap of p-orbitals, which is essential for the delocalization of π electrons across the ring.

### Step 5: Delocalization of Electrons
The extraordinary stability of benzene arises from the delocalization of its π electrons. Instead of being localized between specific carbon atoms, the electrons are spread out over the entire ring. This delocalization can be illustrated by resonance structures:

- One resonance structure shows the double bonds in one arrangement.
- Another resonance structure shows the double bonds shifted to different positions.

This continuous shifting of electrons contributes to the overall stability of the molecule.

### Conclusion
The extraordinary stability of benzene, despite having three double bonds, is due to its aromatic nature, which is a result of satisfying Huckel's rule, being planar, and having delocalized π electrons throughout the ring. This delocalization minimizes the energy of the molecule, making it more stable than expected.

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