Fluorine named the acidic product "fluss-spats-syran" (fluorspar acid). In 1810, the French physicist André-Marie Ampère suggested that hydrogen and an element analogous to chlorine constituted hydrofluoric acid. Sir Humphry Davy proposed that this then-unknown substance be named "fluorine" from fluoric acid and the "-ine" suffix of other halogens. This word, with modifications, is used in most European languages; Greek, Russian, and some others (following Ampère's suggestion) use the name "ftor" or derivatives, from the Greek φθόριος ("phthorios", destructive). The New Latin name "fluorum" gave the element its current symbol F; Fl was used in early papers. Initial studies on fluorine were
Fluorine is used as a defense against herbivores by at least 40 plants in Africa, Australia and Brazil. Other examples include terminally fluorinated fatty acids, fluoroacetone, and 2-fluorocitrate. An enzyme that binds fluorine to carbon – adenosyl-fluoride synthase – was discovered in bacteria in 2002. Elemental fluorine is highly toxic to living organisms. Its effects in humans start at concentrations lower than hydrogen cyanide's 50 ppm and are similar to those of chlorine: significant irritation of the eyes and respiratory system as well as liver and kidney damage occur above 25 ppm, which is the immediately dangerous to life and health