Flu"or*ine (flū"&obreve;r*&ibreve;n or -ēn;
104), n. [NL. fluorina: cf. G.
fluorin, F. fluorine. So called from its occurrence in
the mineral fluorite.] (Chem.) A non-metallic,
gaseous element, strongly acid or negative, and associated with
chlorine, bromine, and iodine, in the halogen group of which it is
the first member. It always occurs combined, is very active
chemically, and possesses such an avidity for most elements, and
silicon especially, that it can neither be prepared nor kept in glass
vessels. If set free it immediately attacks the containing material,
so that it was not isolated until 1886. It is a pungent, corrosive,
colorless gas. Symbol F. Atomic weight 19.
&fist; Fluorine unites with hydrogen to form hydrofluoric
acid, which is the agent employed in etching glass. It occurs
naturally, principally combined as calcium fluoride in
fluorite, and as a double fluoride of aluminium and sodium in
cryolite.
