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Antiaromaticity — Wikipedia (en)

Source: Wikipedia (en)
Original: https://en.wikipedia.org/wiki/Antiaromaticity
License (as archived): CC-BY-SA-4.0
Archived: 2026-11-09T14:20:42.104Z
SHA-256 of the archived text: 6741601fe8c217175585881f52218fa2f96077907f145fade6125d4f6012255a
Stable URL of this page: https://metraipolis.com/documento/dc_0638d96ec022

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Antiaromaticity — Wikipedia (en) — Wikipedia (en), https://en.wikipedia.org/wiki/Antiaromaticity (CC-BY-SA-4.0); archived copy: https://metraipolis.com/documento/dc_0638d96ec022 (Metraipolis archive dc_0638d96ec022, sha256 6741601fe8c217175585881f52218fa2f96077907f145fade6125d4f6012255a)

BibTeX

@misc{dc0638d96ec022,
  title = {Antiaromaticity — Wikipedia (en)},
  howpublished = {Wikipedia (en)},
  url = {https://en.wikipedia.org/wiki/Antiaromaticity},
  note = {License CC-BY-SA-4.0; archived copy https://metraipolis.com/documento/dc_0638d96ec022; sha256 6741601fe8c217175585881f52218fa2f96077907f145fade6125d4f6012255a},
  year = {2026}
}

Archived text

Reproduced under CC-BY-SA-4.0. Attribution: Wikipedia (en), https://en.wikipedia.org/wiki/Antiaromaticity. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

Antiaromaticity is a chemical property of a cyclic molecule with a π electron system that has higher energy, i.e., it is less stable due to the presence of 4n delocalised (π or lone pair) electrons in it, as opposed to aromaticity. Unlike aromatic compounds, which follow Hückel's rule ([4n+2] π electrons) and are highly stable, antiaromatic compounds are highly unstable and highly reactive. To avoid the instability of antiaromaticity, molecules may change shape, becoming non-planar and therefore breaking some of the π interactions. In contrast to the diamagnetic ring current present in aromatic compounds, antiaromatic compounds have a paramagnetic ring current, which can be observed by NMR spectroscopy. Examples of antiaromatic compounds are pentalene (A), biphenylene (B), cyclopentadienyl cation (C). The prototypical example of antiaromaticity, cyclobutadiene, is the subject of debate, with some scientists arguing that antiaromaticity is not a major factor contributing to its destabilization. Cyclooctatetraene is an example of a molecule adopting a non-planar geometry to avoid the destabilization that results from antiaromaticity. If it were planar, it would have a single eight-electron π system around the ring, but it instead adopts a boat-like shape with four individual π bonds. Because antiaromatic compounds are often short-lived and difficult to work with experimentally, antiaromatic destabilization energy is often modeled by simulation rather than by experimentation.

Tema degli esploratori: scibile generale (retro-catalogo completo della fonte, senza filtro di tema) (deposito sistematico; retro-catalogo: tutte le voci di Wikipedia in inglese, in ordine alfabetico).
Fonte: Wikipedia in inglese, voce «Antiaromaticity» — https://en.wikipedia.org/wiki/Antiaromaticity
Wikidata Q574842: «characteristic of a cyclic molecule with a π electron system that has higher energy» (dati Wikidata in CC0 1.0) — https://www.wikidata.org/wiki/Q574842
Autori: i contributori di Wikipedia (cronologia: https://en.wikipedia.org/wiki/Antiaromaticity?action=history).
Licenza: Creative Commons Attribuzione-Condividi allo stesso modo 4.0 (CC BY-SA 4.0) — https://creativecommons.org/licenses/by-sa/4.0/. Il riuso richiede attribuzione e stessa licenza.
Estratto dell'introduzione non modificato nel contenuto; revisione 1362849261, consultata il 2026-11-09T14:17:16.228Z tramite l'API ufficiale di Wikipedia. Impronta SHA-256 dell'estratto: 7e9ef5cc7bb00426ee83e707a233888b1157674c426b8045ee146ca573c3fcd5