King of Carbon Bondage

Today is the birthday of Friedrich Kekulé, a German chemist born in 1829 who laid the foundations of structural organic chemistry. In 1858 Kekulé, who initially studied architecture, set out his theories that carbon atoms tend to form four bonds and will readily link together in chains. He later described his vision of a tetrahedral carbon atom, in which the four bonds are directed as if toward the corners of a tetrahedron.

In 1865, Kekulé also proposed a structure for benzene, a hexagonal ring of six interconnected carbon atoms with alternating single and double bonds. Several years later he introduced the concept of resonance--the average of several possible molecular structures--explaining that benzene oscillates between two different structural forms in which the single and double bonds shift position.

[Source: Roy Porter, Ed., The Biographical Dictionary of Scientists (Oxford University Press, 2nd ed., 1994).]

Posted in Chemistry