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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. Nitronium ion - Wikipedia

    en.wikipedia.org/wiki/Nitronium_ion

    The nitronium ion, [N O 2] +, is a cation.It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion [NH 4] +.It is created by the removal of an electron from the paramagnetic nitrogen dioxide molecule NO 2, or the protonation of nitric acid HNO 3 (with removal of H 2 O).

  4. Nitro compound - Wikipedia

    en.wikipedia.org/wiki/Nitro_compound

    The structure of an organic nitro compound. In organic chemistry, nitro compounds are organic compounds that contain one or more nitro functional groups (−NO 2). The nitro group is one of the most common explosophores (functional group that makes a compound explosive) used globally. The nitro group is also strongly electron-withdrawing.

  5. 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]

  6. Electrophilic aromatic directing groups - Wikipedia

    en.wikipedia.org/wiki/Electrophilic_aromatic...

    Structure Type of electronic effect Directing effect Strong trifluoromethylsulfonyl group [13]-SO 2 CF 3 –I, –M meta (substituted) ammonium groups [14]-NR 3 + (R = alkyl or H) –I nitro group-NO 2 –I, –M sulfonic acids and sulfonyl groups-SO 3 H, -SO 2 R cyano group-C≡N trihalomethyl groups (strongest for -CF 3 group) -CX 3 (X = F ...

  7. 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 ...

  8. 1,3-dipole - Wikipedia

    en.wikipedia.org/wiki/1,3-dipole

    They are reactants in 1,3-dipolar cycloadditions. [1] [2] The dipole has at least one resonance structure with positive and negative charges having a 1,3 relationship which can generally be denoted as + a−b−c −, where a may be a carbon, oxygen or nitrogen, b may be nitrogen or oxygen, and c may be a carbon, oxygen or nitrogen. [3]

  9. Nitrile ylide - Wikipedia

    en.wikipedia.org/wiki/Nitrile_ylide

    The 3-dimensional structure of the nitrilium ylide itself may also provide a clue as to the most appropriate resonance structure, with a linear R–C≡N–C unit supportive of the charge distribution indicated for resonance structures 1a & 1b and also consistent with the nomenclature nitrilium ylide.