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  2. Mesomeric effect - Wikipedia

    en.wikipedia.org/wiki/Mesomeric_effect

    The effect is used in a qualitative way and describes the electron withdrawing or releasing properties of substituents based on relevant resonance structures and is symbolized by the letter M. [2] The mesomeric effect is negative ( –M ) when the substituent is an electron-withdrawing group , and the effect is positive ( +M ) when the ...

  3. Nitrogen dioxide - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_dioxide

    Nitrogen dioxide is a chemical compound with the formula NO 2.One of several nitrogen oxides, nitrogen dioxide is a reddish-brown gas.It is a paramagnetic, bent molecule with C 2v point group symmetry.

  4. Nitrosonium - Wikipedia

    en.wikipedia.org/wiki/Nitrosonium

    The nitrosonium ion is NO +, in which the nitrogen atom is bonded to an oxygen atom with a bond order of 3, and the overall diatomic species bears a positive charge. It can be viewed as nitric oxide with one electron removed.

  5. 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.

  6. Electrophilic aromatic directing groups - Wikipedia

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

    On the other hand, the nitrobenzene resonance structures have positive charges around the ring system: The nitro group can withdraw electron density through resonance. Attack occurs at the meta position, since the (partial) formal positive charges at the ortho and para positions indicate electron deficiency at these positions.

  7. 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).

  8. 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.

  9. 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 ...