1. Definitions

In 1788, Klaproth observed that calcium carbonate crystallized in two different forms: aragonite and calcite. In 1809, Humphrey Davy suggested that diamond and graphite corresponded to two different arrangements of carbon in the solid phase. In 1821, Mitscherlich published his observations on the existence of different crystalline forms for sodium monophosphate in French, introducing the term "polymorphism" . Shortly afterwards, he identified two allotropic forms of sulfur. From then on, the discovery of crystalline forms for given molecules became increasingly frequent. In 1832, Wöhler and Liebig discovered two different...