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  2. Aromaticity - Wikipedia

    en.wikipedia.org/wiki/Aromaticity

    Aromaticity is found in ions as well: the cyclopropenyl cation (2e system), the cyclopentadienyl anion (6e system), the tropylium ion (6e), and the cyclooctatetraene dianion (10e). Aromatic properties have been attributed to non-benzenoid compounds such as tropone. Aromatic properties are tested to the limit in a class of compounds called ...

  3. Specific ultraviolet absorbance - Wikipedia

    en.wikipedia.org/wiki/Specific_ultraviolet...

    Aromatic character is used in the study of dissolved organic matter, from mineral soils, or organic soils, to use as an assay to whether or not dissolved organic carbon in the water is labile, a ready source of energy, or is from a relatively old source of carbon (recalcitrant).

  4. Clar's rule - Wikipedia

    en.wikipedia.org/wiki/Clar's_rule

    Clar's rule states that for a benzenoid polycyclic aromatic hydrocarbon (i.e. one with only hexagonal rings), the resonance structure with the largest number of disjoint aromatic π-sextets is the most important to characterize its chemical and physical properties. Such a resonance structure is called a Clar structure. In other words, a ...

  5. Homoaromaticity - Wikipedia

    en.wikipedia.org/wiki/Homoaromaticity

    Homoaromaticity, in organic chemistry, refers to a special case of aromaticity in which conjugation is interrupted by a single sp 3 hybridized carbon atom. Although this sp 3 center disrupts the continuous overlap of p-orbitals, traditionally thought to be a requirement for aromaticity, considerable thermodynamic stability and many of the spectroscopic, magnetic, and chemical properties ...

  6. Aromatic compound - Wikipedia

    en.wikipedia.org/wiki/Aromatic_compound

    Heteroarenes are aromatic compounds, where at least one methine or vinylene (-C= or -CH=CH-) group is replaced by a heteroatom: oxygen, nitrogen, or sulfur. [3] Examples of non-benzene compounds with aromatic properties are furan, a heterocyclic compound with a five-membered ring that includes a single oxygen atom, and pyridine, a heterocyclic compound with a six-membered ring containing one ...

  7. Aromatization - Wikipedia

    en.wikipedia.org/wiki/Aromatization

    Aromatization is a chemical reaction in which an aromatic system is formed from a single nonaromatic precursor. Typically aromatization is achieved by dehydrogenation of existing cyclic compounds, illustrated by the conversion of cyclohexane into benzene. Aromatization includes the formation of heterocyclic systems.

  8. Hückel's rule - Wikipedia

    en.wikipedia.org/wiki/Hückel's_rule

    8 (cyclooctatetraenide anion), with ten π electrons obeys the 4n + 2 rule for n = 2 and is planar, while the 1,4-dimethyl derivative of the dication, with six π electrons, is also believed to be planar and aromatic. [8] The Cyclononatetraenide anion (C 9 H – 9) is the largest all-cis monocyclic annulene/annulenyl system that is planar and ...

  9. Aromatic amino acid - Wikipedia

    en.wikipedia.org/wiki/Aromatic_amino_acid

    Animals obtain aromatic amino acids from their diet, but nearly [a] all plants and some micro-organisms must synthesize their aromatic amino acids through the metabolically costly shikimate pathway in order to make them. Histidine, phenylalanine, tryptophan, are essential amino acids for animals. Since they are not synthesized in the human body ...