Question

Is styrene considered aromatic?

Answer 1

One might think that because it has `8` `pi` electrons, it is antiaromatic. Actually, the `pi` electrons on the ethylene substituent aren't conjugated within the ring, but outside it. They are localized outside of the ring.

By definition...

• We need `4n + 2` `pi` electrons conjugated within the ring, and we do... `n = 1`.
• Styrene is indeed planar, and it is obviously a ring.
• All of the `p` orbitals within the ring are indeed perpendicular to the ring.

So yes, it is aromatic.

---

Here, you can see that the electrons do conjugate pretty far throughout the ring, but they don't have full mobility.

This does allow the double bond to be easily protonated, but it doesn't disrupt the aromaticity, because benzene (obviously aromatic) can do something similar: