Nomenclature
CAS number: 7784-18-1
Aluminum trifluoride.
AlF
3; mol wt 83.98.
Al 32.13%, F 67.87%.
Description and 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
Monohydrate.
Properties
Orthorhombic crystals, d 2.17.Derivative
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.