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  2. Brooker's merocyanine - Wikipedia

    en.wikipedia.org/wiki/Brooker's_merocyanine

    As shown in the structural formula, MOED can be depicted using two resonance structures: neutral and zwitterionic. Research indicates that the zwitterionic structure is the major contributor to resonance hybrid when the compound exists in polar solvents such as water, and the neutral form when it exists in nonpolar solvents such as chloroform. [2]

  3. 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.

  4. Hydronium - Wikipedia

    en.wikipedia.org/wiki/Hydronium

    In chemistry, hydronium (hydroxonium in traditional British English) is the cation [H 3 O] +, also written as H 3 O +, the type of oxonium ion produced by protonation of water.It is often viewed as the positive ion present when an Arrhenius acid is dissolved in water, as Arrhenius acid molecules in solution give up a proton (a positive hydrogen ion, H +) to the surrounding water molecules (H 2 O).

  5. 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).

  6. 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 ]

  7. Organic azide - Wikipedia

    en.wikipedia.org/wiki/Organic_azide

    The azide functional group can be shown by two resonance structures. An organic azide is an organic compound that contains an azide (– N 3) functional group. [1] Because of the hazards associated with their use, few azides are used commercially although they exhibit interesting reactivity for researchers.

  8. Phosphinidene - Wikipedia

    en.wikipedia.org/wiki/Phosphinidene

    Phospha-Wittig compounds can be viewed as a phosphinidene stabilized by a phosphine. These compounds have been given the label of "phospha-Wittig" as they have two dominant resonance structures (a neutral form and a zwitterionic form) that are analogous to those of the phosphonium ylides that are used in the Wittig reaction.

  9. Meldrum's acid - Wikipedia

    en.wikipedia.org/wiki/Meldrum's_acid

    However, while dimedone exists in solution predominantly as the mono-enol tautomer, Meldrum's acid is almost entirely as the diketone form. [ 2 ] The unusually high acidity of this compound was long considered anomalous—it is 8 orders of magnitude more acidic than the closely related compound dimethyl malonate .