Title: Calcium Fluoride
CAS Registry Number: 7789-75-5
Molecular Formula: CaF2
Molecular Weight: 78.07
Percent Composition: Ca 51.34%, F 48.67%
Literature References: Occurs in nature as the mineral fluorite or fluorspar. Prepd from CaCO3 + HF: O. Ruff, Die Chemie des Fluors (Berlin, 1920) p 89; Emeleus in Fluorine Chemistry vol. I, J. H. Simons, Ed. (Academic Press, 1950) p 36; Kwasnik in Handbook of Preparative Inorganic Chemistry Vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 233. Toxicity study: K.-R. Stratmann, Dtsch. Zahnaerztl. Z. 34, 484 (1979).
Properties: White powder or cubic crystals. When F ions are pptd with Ca 2+ in the absence of CO3 ions, a gel is obtained. For the crystals: d 3.18; mp 1403°; bp 2500°; Mohs' hardness: 4. Becomes luminous when heated. Practically insol in water (soly at 18°: 0.0015 g/100 ml). Slightly sol in dil mineral acids; dissolved by concd mineral acids with liberation of HF. LD50 i.p. in mice: 2638.27 mg/kg (Stratmann).
Melting point: mp 1403°
Boiling point: bp 2500°; Mohs' hardness: 4
Density: d 3.18
Toxicity data: LD50 i.p. in mice: 2638.27 mg/kg (Stratmann)
Use: Fluorspar is the main primary source of fluorine and its compds. In ferrous metallurgy it is used as a flux to increase the fluidity of the slag. The steel industry is the largest consumer; the chemical industry, second and glass and ceramics, third. Synthetic fluorspar is used in the optical industry (transmits u.v. rays), and pure calcium fluoride is used as catalyst in dehydration and dehydrogenations. Used to fluoridate drinking water. |