Aromatic, Anti-Aromatic, and Non-Aromatic Compounds

Aromatic Compounds

Conditions for Aromaticity:
- Must be cyclic.
- Every atom must have a p orbital, thus no sp3 carbons allowed (sp2 or sp carbons are permitted).
- Must be conjugated: pi electrons need to be free to move around in the ring.
- Must be planar (flat, 2D structure).
- Must follow Huckel's Rule: 4n + 2 pi electrons (where n = 0, 1, 2, 3,...) resulting in 2, 6, 10, 14, etc. pi electrons.

Conditions for Anti-Aromaticity:
- Must be cyclic, no sp3 carbons.
- Must be conjugated and planar.
- Follows 4n rule (where n = 1, 2, 3,...), resulting in 4, 8, 12, etc. pi electrons.

Conditions for Non-Aromaticity:
- If any of the conditions for aromatic or anti-aromatic compounds are not met, the compound is non-aromatic.
- Examples include linear molecules, having sp3 carbons, not being conjugated, non-planar molecules, or having an odd number of pi electrons.
Stability:
- Aromatic compounds are very stable.
- Anti-aromatic compounds are unstable.
- Non-aromatic compounds are regular and not particularly stable or unstable.

Properties:
- Cyclic, conjugated, sp2 hybridized, planar.
- Contains 6 pi electrons, follows Huckel's Rule (4n + 2).
- Conclusion: Aromatic, very stable.

Properties:
- Cyclic, conjugated, planar.
- Contains 4 pi electrons, follows 4n rule.
- Conclusion: Anti-aromatic, unstable.

Properties:
- Cyclic, conjugated, sp2 hybridized, planar.
- Contains 10 pi electrons, follows Huckel's Rule.
- Conclusion: Aromatic.

Properties:
- Cyclic, conjugated, planar.
- Contains 14 pi electrons, follows Huckel's Rule.
- Conclusion: Aromatic.

Properties:
- Cyclic but not fully conjugated due to presence of sp3 carbon.
- Conclusion: Non-aromatic.