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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. 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 ]

  4. Bredt's rule - Wikipedia

    en.wikipedia.org/wiki/Bredt's_rule

    In organic chemistry, an anti-Bredt molecule is a bridged molecule with a double bond at the bridgehead. Bredt's rule is the empirical observation that such molecules only form in large ring systems. For example, two of the following norbornene isomers violate Bredt's rule, and are too unstable to prepare: Bridgehead atoms violating Bredt's ...

  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. Aromaticity - Wikipedia

    en.wikipedia.org/wiki/Aromaticity

    Two different resonance forms of benzene (top) combine to produce an average structure (bottom). In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected by the stabilization of conjugation alone.

  7. Mesoionic compounds - Wikipedia

    en.wikipedia.org/wiki/Mesoionic_compounds

    In chemistry, mesoionic compounds are one in which a heterocyclic structure is dipolar and where both the negative and the positive charges are delocalized. [1] A completely uncharged structure cannot be written and mesoionic compounds cannot be represented satisfactorily by any one mesomeric structure. [1] Mesoionic compounds are a subclass of ...

  8. Why OPEC's grip on oil markets will continue to weaken in 2025

    www.aol.com/why-opecs-grip-oil-markets-193512699...

    OPEC+ faces a major oil oversupply in 2025, challenging production increases. The coalition has tried to boost oil prices by holding back output. Instead, members are ceding control to non-OPEC ...

  9. Pauling's principle of electroneutrality - Wikipedia

    en.wikipedia.org/wiki/Pauling's_principle_of...

    There are two possible structures for hydrogen cyanide, HCN and CNH, differing only as to the position of the hydrogen atom. The structure with hydrogen attached to nitrogen, CNH, leads to formal charges of -1 on carbon and +1 on nitrogen, which would be partially compensated for by the electronegativity of nitrogen and Pauling calculated the net charges on H, N and C as -0.79, +0.75 and +0.04 ...