For questions about the concept of aromaticity. Do not use for reactions of aromatic compounds.
Scope
This tag should only be applied to questions about the concept of aromaticity itself. For properties and reactions of aromatic compounds, please use the tag aromatic-compounds instead.
Overview
Aromaticity is defined in the IUPAC Gold Book (DOI: 10.1351/goldbook.A00442) as:
The concept of spatial and electronic structure of cyclic molecular systems displaying the effects of cyclic electron delocalization which provide for their enhanced thermodynamic stability (relative to acyclic structural analogues) and tendency to retain the structural type in the course of chemical transformations.
Traditionally, Hückel's rule is used to determine whether a compound is aromatic or not. Compounds with 4n + 2 pi electrons, where n is a natural number, are considered to be aromatic. Benzene, which has six pi electrons (n = 1), is the classic example of an aromatic compound.
However, the identification and quantification of aromaticity using experimental parameters is still an ongoing area of research.
Further reading
- Carey, F. A.; Sundberg, R. J. Chapter 8: Aromaticity. Advanced Organic Chemistry, Part A: Structure and Mechanisms, 5th ed.; Springer: New York, 2007.
- Advanced: Gleiter, R.; Haberhauer, G. Aromaticity and Other Conjugation Effects; Wiley-VCH: Weinheim, Germany, 2012.
