Joseph Louis Gay-Lussac
It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. Prussian blue lent its name to prussic acid (hydrogen cyanide) derived from it. In German, hydrogen cyanide is called ("blue acid"). French chemist Joseph Louis Gay-Lussac gave cyanide its name, from the Ancient Greek word (, "blue"), because of its Prussian blue color.