Friedrich Wöhler wrote a letter to J. J. Berzelius stating that he had synthesized urea, making an organic compound from inorganic materials, 1828. Wöhler and colleague Justus von Liebig were friends who helped make organic chemistry a field of systematic study.
The most significant result of Wöhler’s and Liebig’s collaboration was their discovery of certain stable groupings of atoms in organic compounds that retain their identity, even when those compounds are transformed into others.
The first such grouping they identified was the “benzoyl radical,” found in 1832 during a study of oil of bitter almonds (benzaldehyde) and its derivatives. Their original objective was to buttress Berzelius’s dualism theory in the realm of organic chemistry by thinking of radicals as organic chemical equivalents of inorganic atoms. But they gradually recognized that the substitutions that chemists effected within radicals—of electropositive hydrogen by electronegative chlorine, for example—seriously threatened dualism as a comprehensive explanation of bonding in organic chemistry. In the long run their identification of radicals can be seen as an early step along the path to structural chemistry.
Visit Chemistry in History to read more about Friedrich Wohler and Justus von Liebig.
Excerpted with permission, Chemical Heritage Foundation