a corrosive, toxic, greenish-yellow gaseous chemical element, one of the halogens and the most reactive nonmetallic element, forming fluorides with almost all known elements: symbol, F; at. no., 9
fluor + -ine
See fluorine in American Heritage Dictionary 4
noun Symbol F
A pale-yellow, highly corrosive, poisonous, gaseous halogen element, the most electronegative and most reactive of all the elements, used in a wide variety of industrially important compounds. Atomic number 9; atomic weight 18.9984; freezing point -219.62°C; melting point -223°C; boiling point -188.14°C; specific gravity of liquid 1.108 (at boiling point); valence 1. See Table at element.