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  2. Sigma-pi and equivalent-orbital models - Wikipedia

    en.wikipedia.org/wiki/Sigma-pi_and_equivalent...

    Linus Pauling proposed that the double bond in ethylene results from two equivalent tetrahedral orbitals from each atom, [5] which later came to be called banana bonds or tau bonds. [6] Erich Hückel proposed a representation of the double bond as a combination of a sigma bond plus a pi bond.

  3. Pi bond - Wikipedia

    en.wikipedia.org/wiki/Pi_bond

    Two pi bonds are the maximum that can exist between a given pair of atoms. Quadruple bonds are extremely rare and can be formed only between transition metal atoms, and consist of one sigma bond, two pi bonds and one delta bond. A pi bond is weaker than a sigma bond, but the combination of pi and sigma bond is stronger than either bond by itself.

  4. Valence bond theory - Wikipedia

    en.wikipedia.org/wiki/Valence_bond_theory

    Sigma bonds occur when the orbitals of two shared electrons overlap head-to-head, with the electron density most concentrated between nuclei. Pi bonds occur when two orbitals overlap when they are parallel. [9] For example, a bond between two s-orbital electrons is a sigma bond, because two spheres are always coaxial. In terms of bond order ...

  5. Sigma bond - Wikipedia

    en.wikipedia.org/wiki/Sigma_bond

    There is no more than 1 sigma bond between any two atoms. Molecules with rings have additional sigma bonds, such as benzene rings, which have 6 C−C sigma bonds within the ring for 6 carbon atoms. The anthracene molecule, C 14 H 10, has three rings so that the rule gives the number of sigma bonds as 24 + 3 − 1 = 26. In this case there are 16 ...

  6. Ligand field theory - Wikipedia

    en.wikipedia.org/wiki/Ligand_field_theory

    The six bonding molecular orbitals that are formed are "filled" with the electrons from the ligands, and electrons from the d-orbitals of the metal ion occupy the non-bonding and, in some cases, anti-bonding MOs. The energy difference between the latter two types of MOs is called Δ O (O stands for octahedral) and is determined by the nature of ...

  7. Orbital hybridisation - Wikipedia

    en.wikipedia.org/wiki/Orbital_hybridisation

    In ethene, the two carbon atoms form a σ bond by overlapping one sp 2 orbital from each carbon atom. The π bond between the carbon atoms perpendicular to the molecular plane is formed by 2p–2p overlap. Each carbon atom forms covalent C–H bonds with two hydrogens by s–sp 2 overlap, all with 120° bond angles. The hydrogen–carbon bonds ...

  8. Mass spectral interpretation - Wikipedia

    en.wikipedia.org/wiki/Mass_spectral_interpretation

    The ionization of alkanes weakens the C-C bond, ultimately resulting in the decomposition. [7] As the bond breaks, a charged, even electron species (R+) and a neutral radical species (R•) are generated. Highly substituted carbocations are more stable than the nonsubstituted ones. An example is depicted below. Sigma bond cleavage of an alkane.

  9. Molecular orbital - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital

    In hydrogen fluoride HF overlap between the H 1s and F 2s orbitals is allowed by symmetry but the difference in energy between the two atomic orbitals prevents them from interacting to create a molecular orbital. Overlap between the H 1s and F 2p z orbitals is also symmetry allowed, and these two atomic orbitals have a small energy separation ...