enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  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. Hyperconjugation - Wikipedia

    en.wikipedia.org/wiki/Hyperconjugation

    In organic chemistry, hyperconjugation (σ-conjugation or no-bond resonance) refers to the delocalization of electrons with the participation of bonds of primarily σ-character. Usually, hyperconjugation involves the interaction of the electrons in a sigma (σ) orbital (e.g. C–H or C–C) with an adjacent unpopulated non-bonding p or ...

  4. 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 ...

  5. Conjugated system - Wikipedia

    en.wikipedia.org/wiki/Conjugated_system

    Cinnamaldehyde is a naturally-occurring compound that has a conjugated system penta-1,3-diene is a molecule with a conjugated system Diazomethane conjugated pi-system. In theoretical chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in a molecule, which in general lowers the overall energy of the molecule and increases stability.

  6. Hydrogen bond - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_bond

    Consequently, hydrogen bonds between or within solute molecules dissolved in water are almost always unfavorable relative to hydrogen bonds between water and the donors and acceptors for hydrogen bonds on those solutes. [44] Hydrogen bonds between water molecules have an average lifetime of 10 −11 seconds, or 10 picoseconds. [45]

  7. Negative hyperconjugation - Wikipedia

    en.wikipedia.org/wiki/Negative_hyperconjugation

    In organic chemistry, negative hyperconjugation is the donation of electron density from a filled π- or p-orbital to a neighboring σ *-orbital. [1] This phenomenon, a type of resonance, can stabilize the molecule or transition state. [2] It also causes an elongation of the σ-bond by adding electron density to its antibonding orbital. [1]

  8. 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 ]

  9. Markovnikov's rule - Wikipedia

    en.wikipedia.org/wiki/Markovnikov's_rule

    The hydroxyl group (OH) bonds to the carbon that has the greater number of carbon-carbon bonds, while the hydrogen bonds to the carbon on the other end of the double bond, that has more carbon–hydrogen bonds. The chemical basis for Markovnikov's Rule is the formation of the most stable carbocation during the addition process. Adding the ...