mesoionic compound

Fetched 2026-10-26 (cache).

Datamuse reports no synonyms or antonyms for this word.

Noun

1. {{lb|en|chemistry}} any of a class of compounds having five-membered [[ring]] [[heterocycle]]s (or their [[benzo]] derivatives) which possess a [[sextet]] of π-[[electron]]s in association with the [[atom]]s comprising the ring, but which cannot be represented by any one [[covalent]] or [[polar]] [[structure]]; typically the ring structure contains both positive and negative [[delocalised]] [[charges]] which cannot be associated with any one ring atom, and the negative charge can also be associated with a [[conjugated]] [[exocyclic]] atom (typically oxygen, sulfur, or nitrogen).

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