Organic chemistry is the study of carbon and its compounds. Because of carbon's unique position in the periodic table (second period, group IV), it is able to form a very large number of stable compounds due to its size and ability to form single, double, and triple bonds with other elements. Organic molecules and functionalized organic molecules span an enormous range of types and functionalities. These include familiar compounds such as simple hydrocarbons that underly the oil-based economy, conjugated systems, which are currently being studied extensively for their potential use in molecular electronics and organic semiconductors, fullerenes, for their ability to confine molecules and molecular wires, and a whole host of other fascinating yet relatively simple systems.
In this chapter, we will apply the quantum mechanical concepts we have
introduced for chemical bonding to study how chemical bonding in organic
molecules and their derivatives works. Generally, this requires combining
ideas from the valence bond theory and the LCAO theories, as we will
demonstrate below.