Kekule Von Stradonitz, Friedrich August (1829-1896)

was a German chemist who laid the foundations of modern organic chemistry. Organic chemistry is the field of research and industry that is concerned with chemical compounds based on carbon. Because of its particular atomic structure, carbon is able to form a tremendous number and variety of compounds. Carbon atoms can link with other carbon atoms as well as with atoms of other elements. Carbon often bonds with hydrogen, oxygen, nitrogen, or various combinations of these elements. All life as we know it is based on organic chemistry. Also, all the fossil fuels that we use are organic compounds. So are many medicines, including penicillin, for instance. Today, chemical research laboratories constantly synthesize, that is, make, new organic compounds. These are used for many purposes, from plastics to insect-killing substances. Kekule' discovered several important principles of organic chemistry. First, he realized that the carbon atom is tetravalent; that is, it has four valences. A valence is the ability of one electron of an atom to combine with free electrons of other atoms. Thus, carbon has four such free electrons. Kekule' also understood that the four valences in a carbon atom are spread evenly apart. As a result, the structure of the carbon atom can be imagined as a tetrahedron (a pyramid with equal sides). This idea is helpful when examining the structure of organic compounds.
From these insights, Kekule' concluded that carbon and other elements bond together to form long chains of molecules. Kekule' then applied his new understanding to the study of benzene, an organic substance. Kekule' tried tc determine the chemical structure of benzene. He grappled with this problem with little success. Then one night in a dream, he saw the benzene molecule as a snake chasing its tail in a circle. When he woke up, Kekule' knew he had the solution for benzene's molecular structure: it is shaped like a ring. This story that often been quoted as a striking example of the subconscious (dreaming) mind helping the conscious (waking) mind solve a problem. Kekule's solution of benzene structure opened new avenues of study and research in organic chemistry.