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  2. 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 ...

  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. Natural resonance theory - Wikipedia

    en.wikipedia.org/wiki/Natural_Resonance_Theory

    Below is an example of how NRT may generate a list of resonance structures. (1) Given an input wavefunction, NRT creates a list of reference Lewis structures. The LEWIS option tests each structure and rejects those that do not conform to the Lewis bonding theory (i.e., those that do not fulfill the octet rule, pose unreasonable formal charges ...

  5. Natural bond orbital - Wikipedia

    en.wikipedia.org/wiki/Natural_bond_orbital

    In resonance structures, major and minor contributing structures may exist. For amides, for example, NBO calculations show that the structure with a carbonyl double bond is the dominant Lewis structure. However, in NBO calculations, "covalent-ionic resonance" is not needed due to the inclusion of bond-polarity effects in the resonance ...

  6. Linnett double-quartet theory - Wikipedia

    en.wikipedia.org/wiki/Linnett_Double-Quartet_Theory

    One of the main benefits is that many molecular structures, such as molecular oxygen and ozone, can be represented using a single LDQ structure without invoking any resonance structures. This lesser reliance on resonance structures is favourable as, according to Linnett, resonance structures are not satisfactory descriptions of bonding as the ...

  7. Tetrahedral molecular geometry - Wikipedia

    en.wikipedia.org/wiki/Tetrahedral_molecular_geometry

    In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron.The bond angles are arccos(− ⁠ 1 / 3 ⁠) = 109.4712206...° ≈ 109.5° when all four substituents are the same, as in methane (CH 4) [1] [2] as well as its heavier analogues.

  8. 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 ...

  9. Mesomeric effect - Wikipedia

    en.wikipedia.org/wiki/Mesomeric_effect

    It is important to note that the energy of the actual structure of the molecule, i.e. the resonance hybrid, may be lower than that of any of the contributing canonical structures. The difference in energy between the actual inductive structure and the (most stable contributing structures) worst kinetic structure is called the resonance energy ...