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  2. Clar's rule - Wikipedia

    en.wikipedia.org/wiki/Clar's_rule

    Phenanthrene can be thought of as a benzene moiety with two fused rings; a third ring can be fused to obtain triphenylene, with three aromatic π-sextets in its Clar structure. The chemical stability of these molecules is greatly influenced by the degree of aromaticity of their Clar structures.

  3. Hückel's rule - Wikipedia

    en.wikipedia.org/wiki/Hückel's_rule

    Hückel's rule can also be applied to molecules containing other atoms such as nitrogen or oxygen. For example pyridine (C 5 H 5 N) has a ring structure similar to benzene, except that one -CH- group is replaced by a nitrogen atom with no hydrogen. There are still six π electrons and the pyridine molecule is also aromatic and known for its ...

  4. Benzene - Wikipedia

    en.wikipedia.org/wiki/Benzene

    Benzene is an organic chemical compound with the molecular formula C 6 H 6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a natural constituent of petroleum and is ...

  5. Inductive effect - Wikipedia

    en.wikipedia.org/wiki/Inductive_effect

    The inductive effect can be used to determine the stability of a molecule depending on the charge present on the atom and the groups bonded to the atom. For example, if an atom has a positive charge and is attached to a - I group its charge becomes 'amplified' and the molecule becomes more unstable.

  6. Aromaticity - Wikipedia

    en.wikipedia.org/wiki/Aromaticity

    Two different resonance forms of benzene (top) combine to produce an average structure (bottom). In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected by the stabilization of conjugation alone.

  7. Chemical stability - Wikipedia

    en.wikipedia.org/wiki/Chemical_stability

    In chemistry, chemical stability is the thermodynamic stability of a chemical system, in particular a chemical compound or a polymer. [ 1 ] Thermodynamic stability occurs when a system is in its lowest energy state , or in chemical equilibrium with its environment.

  8. Ortho effect - Wikipedia

    en.wikipedia.org/wiki/Ortho_effect

    This is caused by steric effects and bonding interactions along with polar effects caused by the various substituents which are in a given molecule, resulting in changes in its chemical and physical properties. The ortho effect is associated with substituted benzene compounds. There are three main ortho effects in substituted benzene compounds:

  9. Ring strain - Wikipedia

    en.wikipedia.org/wiki/Ring_strain

    In alkanes, optimum overlap of atomic orbitals is achieved at 109.5°. The most common cyclic compounds have five or six carbons in their ring. [6] Adolf von Baeyer received a Nobel Prize in 1905 for the discovery of the Baeyer strain theory, which was an explanation of the relative stabilities of cyclic molecules in 1885.