524. Ammonium Hexafluoroaluminate

Nomenclature

CAS number: 7784-19-2
(OC-6-11)-Hexafluoroaluminate(3) ammonium (1:3); ammonium cryolite; ammonium aluminum fluoride; ammonium fluoaluminate.
AlF6H12N3; mol wt 195.09.
Al 13.83%, F 58.43%, H 6.20%, N 21.54%.
(NH4)3AlF6.

Description and references

Prepn from ammonium fluoride and aluminum hydroxide: v. Helmolt, Z. Anorg. Allg. Chem. 3, 127 (1893); Petersen, J. Prakt. Chem. [2] 40, 55 (1889); Kwasnik in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed. 1963) p 236.

Properties

Cubic crystals, d 1.78. Thermally stable to above 100°. Freely sol in water. Does not attack glass.

Use

Prepn of pure aluminum fluoride.