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  2. Resonance (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Resonance_(chemistry)

    Contributing structures of the carbonate ion. In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, [1] also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.

  3. Mesomeric effect - Wikipedia

    en.wikipedia.org/wiki/Mesomeric_effect

    In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound.It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. [1]

  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. Valence bond theory - Wikipedia

    en.wikipedia.org/wiki/Valence_bond_theory

    A valence bond structure resembles a Lewis structure, but when a molecule cannot be fully represented by a single Lewis structure, multiple valence bond structures are used. Each of these VB structures represents a specific Lewis structure. This combination of valence bond structures is the main point of resonance theory.

  6. Lewis structure - Wikipedia

    en.wikipedia.org/wiki/Lewis_structure

    Expressing resonance when drawing Lewis structures may be done either by drawing each of the possible resonance forms and placing double-headed arrows between them or by using dashed lines to represent the partial bonds (although the latter is a good representation of the resonance hybrid which is not, formally speaking, a Lewis structure ...

  7. Natural resonance theory - Wikipedia

    en.wikipedia.org/wiki/Natural_Resonance_Theory

    In computational chemistry, natural resonance theory (NRT) is an iterative, variational functional embedded into the natural bond orbital (NBO) program, commonly run in Gaussian, GAMESS, ORCA, Ampac and other software packages.

  8. Transition-metal allyl complex - Wikipedia

    en.wikipedia.org/wiki/Transition-metal_allyl_complex

    Structure of allylpalladium chloride dimer. Transition-metal allyl complexes are coordination complexes with allyl and its derivatives as ligands.Allyl is the radical with the connectivity CH 2 CHCH 2, although as a ligand it is usually viewed as an allyl anion CH 2 =CH−CH 2 −, which is usually described as two equivalent resonance structures.

  9. Nitromethane - Wikipedia

    en.wikipedia.org/wiki/Nitromethane

    Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula CH 3 NO 2.It is the simplest organic nitro compound.It is a polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent.