Yellowish in color, almost invisible, fluorine (F2) is distinguished by its repulsive odor , detectable from 0.02 ppm. It is a very toxic gas by inhalation (R26) and corrosive to the point of causing burns (R35) to the skin and eyes. Fluorine is an oxidizer , which means that it promotes the ignition of combustible materials (R8). Being one of the most reactive elements in all of chemistry , it reacts with almost all mineral and organic substances.