Friedrich Wöhler and Justus von Liebig prove by experiment that a group of carbon, hydrogen, and oxygen atoms can behave like an element, take the place of an element, and be exchanged for elements in chemical compounds, in their published investigation of the oil of bitter almonds in 1834.

Thus the foundation is laid of the doctrine of compound radicals, a doctrine which is to have a profound influence on the development of chemistry.

Wöhler, the first to synthesize urea, is also known for being a co-discoverer of beryllium, silicon and silicon nitride, as well as the synthesis of calcium carbide, among others.