Why there is an unhybrid orbital in sp2 hybridization?

looney_tunes

(This has to be quite simplified to be intelligible - reference to an organic chemistry text will proved much more detail.) sp hybridization is a model used to explain the bond formation in carbon compounds (chosen as the simplest example as it only has a few electrons - in transition metals things get a lot more complicated), in which electrons behave as it they are partially in s orbitals and partially in p orbitals. When carbon forms 4 'single bonds', all four electrons act the same, and this is referred to as sp3 hybridization. When it forms a double bond, two of the electrons form the carbon-carbon bond ( called a sigma bond) by overlapping two sp hybrid orbitals; this is referred to as sp2 hybridization. The other two bonds are formed by overlapping of an s and an sp orbital. This is only a model to help visualize what is going on at an atomic/molecular level. "Why" the different types of hybrid formed can only be explained using more sophisticated mathematical techniques, way beyond the scope of trivia. http://en.wikipedia.org/wiki/Orbital_hybridisation Nov 13 09, 2:25 PM