Friedrich Wöhler (1800–1882) and [[von Liebig, Justus|Justus von Liebig] (1803–1873) were friends who helped make organic chemistry a field of systematic study within the framework of known chemical laws. Years after their work, the insights gained from organic chemistry about how atoms bond were applied to the whole of chemistry.
Wöhler, driven by a need to obtain the finest education in chemistry, went to Sweden to study with Jons Jakob Berzellus after taking his medical degree at the University of Heidelberg. Even after returning to Germany, Wöhler remained Berzelius's loyal supporter for many years, translating several editions of Berzelius's textbook into German as well as his annual reports on chemical progress. The University of Göttingen, where Wöhler taught for nearly 50 years, became an international mecca for chemistry graduate students.
Perhaps the most famous creation of an isomeric compound was Wöhler's accidental synthesis of urea in 1828, when he was attempting to prepare ammonium cyanate (which he later succeeded in preparing by allowing the crystals to form at room temperature instead of by evaporating the solution). The feat of imitating nature in the laboratory was a truly exciting experience—as Wöhler expressed it in his often-quoted letter to Berzelius: "I can no longer, so to speak, hold my chemical water and must tell you that I can make urea without needing a kidney, whether of man or dog; the ammonium salt of cyanic acid is urea."
The friendship between Wöhler and Liebig began in 1825 after they amicably resolved a dispute over two substances that had apparently the same composition—cyanic acid and fulminic acid—but very different characteristics: the silver compound of fulminic acid, investigated by Liebig, was explosive, whereas silver cyanate, as Wöhler found, was not. These and similar substances, called "isomers," led chemists to suspect that substances are defined not simply by the number and kind of atoms in the molecule but also by the arrangement of those atoms.
The most significant result of Liebig and Wöhler'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, an early step along the path to structural chemistry.
In the 1840s Liebig and Wöhler moved away from fundamental research in organic chemistry. Wöhler returned to his early inorganic chemistry interests, having successfully extracted aluminum and beryllium from their compounds by chemical means in 1827, the same year he synthesized urea. Among other contributions he prepared calcium carbide and discovered various silicon compounds, demonstrating close analogies to the chemistry of carbon.