Using VSEPR Theory to Predict Hybridization

Using VSEPR Theory to Predict Hybridization

If we know the geometry of a molecule, we can predict the kind of hybrid orbitals that are used. Since VSEPR works so well in predicting geometry, we can use it to help us obtain information on the hybrid orbitals. For example, the Lewis structures of CH₄ and SF₆ are

In CH₄, there are four electron pairs around carbon. The VSEPR model tells us that they should be arranged tetrahedrally. The only hybrid orbitals that are tetrahedral are sp³ hybrids, and we have seen that they explain the structure of this molecule well. Similarly, the VSEPR theory tells us that the six electron pairs around sulphur should be arranged octahedrally. The only octahedrally orientated hybrids are sp³d² - the sulphur in the SF₆ molecules must have these hybrids.