Von Liebig, Justus
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Justus von Liebig (1803–1873) and Friedrich Wöhler (1800–1882) 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.
Liebig's five-bulbed apparatus, seen lying on the table in the portrait photograph. It was filled with a solution of caustic potash and used to collect carbon dioxide after burning a weighed sample to determine the percentage of carbon. Over the years it became the insignia of Liebig's students.
Liebig learned to perform chemical operations as a child in his father's small laboratory, which was maintained to support the family drug and painting-materials business in Darmstadt, Germany. After Liebig finished his university studies in Germany, his ambitions led him to work in Paris with Joseph Louis Gay-Lussac, who was in the forefront of chemical research at that time. Liebig was soon appointed to the University of Giessen where he created a model laboratory for training graduate students that was widely imitated in Europe and later on in the United States. From Giessen, he also edited the journal that was to become the preeminent publication in chemistry—Annalen der Chemie und Pharmacie. After 25 years at Giessen Liebig moved on to the University of Munich.
The friendship between Liebig and Wöhler 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. Among Liebig's new passions were agricultural chemistry and physiology—interests that influenced a number of his American students, who founded agricultural experimental stations and agricultural education in the United States.
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