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  2. 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 ]

  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. 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.

  5. Pi electron donor-acceptor - Wikipedia

    en.wikipedia.org/wiki/Pi_electron_donor-acceptor

    The pEDA parameter for a given substituent is calculated by means of quantum chemistry methods. The model molecule is the monosubstituted benzene. First the geometry should be optimized at a suitable model of theory, then the natural population analysis within the framework of Natural Bond Orbital theory is performed. The molecule have to be ...

  6. 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 ...

  7. Resonance fluorescence - Wikipedia

    en.wikipedia.org/wiki/Resonance_fluorescence

    Resonance fluorescence is the process in which a two-level atom system interacts with the quantum electromagnetic field if the field is driven at a frequency near to the natural frequency of the atom.

  8. Nitric oxide - Wikipedia

    en.wikipedia.org/wiki/Nitric_oxide

    Nitric oxide (nitrogen oxide or nitrogen monoxide [1]) is a colorless gas with the formula NO.It is one of the principal oxides of nitrogen.Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula (• N=O or • NO).

  9. Formal charge - Wikipedia

    en.wikipedia.org/wiki/Formal_charge

    Formal charges in ozone and the nitrate anion. In chemistry, a formal charge (F.C. or q*), in the covalent view of chemical bonding, is the hypothetical charge assigned to an atom in a molecule, assuming that electrons in all chemical bonds are shared equally between atoms, regardless of relative electronegativity.