Organic Chemistry/Foundational concepts of organic chemistry/Atomic structure/Hybridization

From Wikibooks, open books for an open world
Jump to: navigation, search

Hybridization refers to the combining of the orbitals of two or more covalently bonded atoms. Depending on how many free electrons a given atom has and how many bonds it is forming, it will hybridize in a certain manner. The electrons in the s and the p orbitals combine in certain manners to form the bonds. In particular, for most of the atoms of interest in organic chemistry (which form at most four bonds), the more free electrons an atom has, the less "p" character the hybridized bond will have, because the free electrons will take up some space of the p orbitals.

It is easy to determine the hybridization of an atom given a Lewis structure. First, you count the number of pairs of free electrons and the number of sigma bonds (single bonds). Do not count double bonds, since they do not affect the hybridization of the atom. Once the total of these two is determined, the hybridization pattern is as follows:

Sigma Bonds + Electron Pairs     Hybridization
              2                       sp
              3                       sp2
              4                       sp3

The pattern here is the same as that for the electron orbitals, which serves as a memory guide.