Absolutely Small, Chapter 18: Aromatic Molecules

Here the bonding and properties of a very important class of molecules is described. These are called aromatic molecules because they smell sweet and are the basis for perfumes. Aromatic molecules are important in biology, chemistry, and materials science. They have many double bonds that combine together to form what are called delocalized molecular orbitals. Such molecules can absorb light strongly and are responsible for the colors of many things from green leaves to the dyes used to color clothes. The ideas presented about aromatic molecules, that is, delocalized molecular orbitals, are necessary for the next chapter to explain metals, insulators, and semiconductors.