Title: Aluminum Fluoride
CAS Registry Number: 7784-18-1
Additional Names: Aluminum trifluoride
Molecular Formula: AlF3
Molecular Weight: 83.98
Percent Composition: Al 32.13%, F 67.87%
Literature References: Prepd by heating (NH4)3AlF6 to red heat in a stream of nitrogen: Witt, Barrow, Trans. Faraday Soc. 55, 730 (1959); Kwasnik in Handbook of Preparative Inorganic Chemistry Vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 225. Review: Kemmitt, Sharp, Adv. Fluorine Chem. 4, 154-155 (1965).
Properties: Hexagonal crystals. Sublimes (760 mm) 1272°. Soly in water (25°) 0.559 g/100 ml. Sparingly sol in acids and alkalies, even hot concd H2SO4 has little effect. Hydrolyzed by superheated steam at 300-400°.
Derivative Type: Monohydrate
Additional Names: Fluellite
Properties: Orthorhombic crystals, d 2.17.
Density: d 2.17
Derivative Type: Trihydrate
Properties: Usually AlF3.3.1H2O. Prepn: Ehret, Frere, J. Am. Chem. Soc. 67, 64 (1945). Loses water at 100°, more at 200°. It does not seem possible to obtain the anhydrous compd free from oxides by dehydration of the hydrates.
CAUTION: Less toxic on ingestion than other fluorides because of slight solubility.
Use: In ceramics, as flux in metallurgy, in aluminum manufacture, as inhibitor of fermentation, as catalyst in organic reactions. |