Organic Molecules with Multiple Bonds

So far, we have looked at only three types of electronic substructure occurring in molecules: atomic cores, single bonds and lone pairs. There are a lot more to be investigated. We must, therefore, continue our investigation of the different types of environment-insensitive electronic substructures in molecules. In some ways, a consideration of the presence of multiple bonds in polyatomic molecules is easier and more direct than the approach of the problem through diatomics. The rather exceptional high (cylindrical) symmetry of diatomic molecules complicates matters rather than simplifying them. There is, for example, no diatomic molecule in which there is a double bond of the type found in thousands of organic molecules: two bond pairs. Also, of course, along with lone pairs, it is the existence of multiple bonds in organic molecules which gives them their interesting and valuable chemical properties. We must, therefore, take a careful look at double and triple bonds in organic molecules.