History of Chemical Notations from Alchemy to Psycho-Chemistry

Writing involves the transformation of ideas, emotions and sounds into graphic form. Ideagrams help clarify complex ideas and can be considered to be forms of stored memory. The emergence of chemistry from alchemy involved the adaptation of graphic notations to comprehend the invisible atomic and molecular structures of complex matter, and to spread and store that knowledge. This culminated in the molecular representations of chemical reactions and chemical compounds such as natural products, sugars, polymers, proteins and metal complexes. We review the development of textual and graphic notations of chemical structures from circa-1700 to now. We present a Timeline that graphically summarizes the salient stages in the evolution of chemical notations (“chemography”) from alchemy, leading to modern “psycho-chemistry”. The Timeline correlates the emergence of new chemical notations with crucial technological inventions.