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  2. Cycloalkane - Wikipedia

    en.wikipedia.org/wiki/Cycloalkane

    In organic chemistry, the cycloalkanes (also called naphthenes, but distinct from naphthalene) are the monocyclic saturated hydrocarbons. [1] In other words, a cycloalkane consists only of hydrogen and carbon atoms arranged in a structure containing a single ring (possibly with side chains), and all of the carbon-carbon bonds are single.

  3. Cyclic compound - Wikipedia

    en.wikipedia.org/wiki/Cyclic_compound

    Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size (e.g., < 17 total atoms) numbers in the many billions. Cyclic compound examples: All-carbon (carbocyclic) and more complex natural cyclic compounds

  4. Hückel's rule - Wikipedia

    en.wikipedia.org/wiki/Hückel's_rule

    The (4n+2) rule is a consequence of the degeneracy of the π orbitals in cyclic conjugated hydrocarbon molecules. As predicted by Hückel molecular orbital theory, the lowest π orbital in such molecules is non-degenerate and the higher orbitals form degenerate pairs. For benzene the lowest π orbital is non-degenerate and can hold 2 electrons ...

  5. Polycyclic aromatic hydrocarbon - Wikipedia

    en.wikipedia.org/.../Polycyclic_aromatic_hydrocarbon

    A Polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. Most are produced by the incomplete combustion of organic matter — by engine exhaust fumes, tobacco, incinerators, in roasted meats and cereals, [ 1 ] or when biomass burns at lower temperatures as in forest fires .

  6. Heterocyclic compound - Wikipedia

    en.wikipedia.org/wiki/Heterocyclic_compound

    A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). [1] Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles .

  7. 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 ...

  8. Hückel method - Wikipedia

    en.wikipedia.org/wiki/Hückel_method

    In fact, all cyclic conjugated hydrocarbons with a total of 4n π-electrons share this molecular orbital pattern, and this forms the basis of Hückel's rule. Dewar reactivity numbers deriving from the Hückel approach correctly predict the reactivity of aromatic systems with nucleophiles and electrophiles.

  9. 1,5-Cyclooctadiene - Wikipedia

    en.wikipedia.org/wiki/1,5-Cyclooctadiene

    1,5-Cyclooctadiene (also known as cycloocta-1,5-diene) is a cyclic hydrocarbon with the chemical formula C 8 H 12, specifically [−(CH 2) 2 −CH=CH−] 2.. There are three configurational isomers with this structure, that differ by the arrangement of the four C–C single bonds adjacent to the double bonds.