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  2. Sigma bond - Wikipedia

    en.wikipedia.org/wiki/Sigma_bond

    According to the sigma bond rule, the number of sigma bonds in a molecule is equivalent to the number of atoms plus the number of rings minus one. N σ = N atoms + N rings − 1. This rule is a special-case application of the Euler characteristic of the graph which represents the molecule. A molecule with no rings can be represented as a tree ...

  3. Molecular orbital diagram - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital_diagram

    This MO is called the bonding orbital and its energy is lower than that of the original atomic orbitals. A bond involving molecular orbitals which are symmetric with respect to any rotation around the bond axis is called a sigma bond (σ-bond). If the phase cycles once while rotating round the axis, the bond is a pi bond (π-bond).

  4. Category:Chemical bonding - Wikipedia

    en.wikipedia.org/wiki/Category:Chemical_bonding

    Carbon–oxygen bond; Carbon–hydrogen bond; Catch bond; Cation–π interaction; Cation–cation bond; Chalcogen bond; Charge-shift bond; Chemical bonding model; Chemical bonding of water; Chemical specificity; Compliance constants; Cooperative binding; Cooperativity; Coordinate covalent bond; Coordination geometry; Ligand isomerism ...

  5. Sigmatropic reaction - Wikipedia

    en.wikipedia.org/wiki/Sigmatropic_reaction

    Sigmatropic rearrangements are concisely described by an order term [i,j], which is defined as the migration of a σ-bond adjacent to one or more π systems to a new position (i−1) and (j−1) atoms removed from the original location of the σ-bond. [3]

  6. Carbon–carbon bond - Wikipedia

    en.wikipedia.org/wiki/Carbon–carbon_bond

    The carbon–carbon single bond is a sigma bond and is formed between one hybridized orbital from each of the carbon atoms. In ethane, the orbitals are sp 3-hybridized orbitals, but single bonds formed between carbon atoms with other hybridizations do occur (e.g. sp 2 to sp 2). In fact, the carbon atoms in the single bond need not be of the ...

  7. Bond cleavage - Wikipedia

    en.wikipedia.org/wiki/Bond_cleavage

    The triplet and singlet excitation energies of a sigma bond can be used to determine if a bond will follow the homolytic or heterolytic pathway. [2] A metal−metal sigma bond is an exception because the bond's excitation energy is extremely high, thus cannot be used for observation purposes. [2] In some cases, bond cleavage requires catalysts.

  8. Sigma complex - Wikipedia

    en.wikipedia.org/wiki/Sigma_complex

    Transition metal alkane complexes (e.g., a methane complex) that bind solely through the C–H bond are also known but structurally characterized examples are rare, as C–H σ-bonds are generally poor electron donors, and, in many cases, the weakened C–H bond cleaves completely (C–H oxidative addition) to form a complex of type M(R)(H). [1]

  9. Ring (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Ring_(chemistry)

    A simple ring contains the same number of sigma bonds as atoms, and a polycyclic ring system contains more sigma bonds than atoms. A molecule containing one or more rings is called a cyclic compound, and a molecule containing two or more rings (either in the same or different ring systems) is termed a polycyclic compound.