FLUORESCIN
Flu`o*res"cin, n. (Chem.)
Defn: A colorless, amorphous substance which is produced by the reduction of fluoresceïn, and from which the latter may be formed by oxidation.
FLUORIC
Flu*or"ic, a. Etym: [Cf. F. fluorique.] (Chem.)
Defn: Pertaining to, obtained from, or containing, fluorine.
FLUORIDE
Flu"or*ide ( or ; 104), n. Etym: [Cf. F. fluoride.] (Chem.)
Defn: A binary compound of fluorine with another element or radical.
Calcium fluoride (Min.), fluorite, CaF2. See Fluorite.
FLUORINE
Flu"or*ine ( or ; 104), n. Etym: [NL. fluorina: cf. G. fluorin, F.
fluorine. So called from its occurrence in the mineral fluorite.]
(Chem.)
Defn: A non-metallic, gaseous element, strongly acid or negative, or 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.
Note: 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.
FLUORITE
Flu"or*ite, n. (Min.)