Beginning Organic Chemistry (BOC)
1. Basic Knowledge
e. Molecular Orbitals and Bonding
1. Single Bonds

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Bonding in Methane and Ethane. Single Bonds.

Models of these two compounds.

methane ethane

Using the right mouse button (Windows) when the cursor is on one of the models look at the structures in both stick and space filling modes.

Note that the geometry at the carbon centre is tetrahedral (approximately). Because the simple atomic orbitals (s, p) are not organized in the correct geometry, hybridization is carried out to give atomic orbitals which do have the correct geometry. Hybridization is a mathematical mixing and averaging of the ground state atomic orbitals and the orbitals mixed together are those required to give the correct geometry. For a tetrahedral geometry all four s and p orbitals are mixed and the resulting four orbitals giving the tetrahedral geometry are designated sp3 orbitals. Sometimes the tetrahedral carbon is referred to as an sp3 carbon (or centre). Interaction of hybridized atomic orbitals to form bonds gives an electron wave form that is symmetrical about the bond axis and so does not hinder the rotation of one carbon with respect to the other at this bond. Such a symmetrical bond is termed a sigma (s) bond.

A model of the sp3 hybrid orbital is available on the U of Arizona web site.

Date created: 2005 06 09.