Nomenclature
CAS number: 15096-52-3
Kryolith; ice spar; sodium aluminum fluoride.
AlF
6Na
3; mol wt 209.94.
Al 12.85%, F 54.30%, Na 32.85%.
3NaF.AlF
3.
Description and references
A mineral named for its resemblance to ice;
large deposits existed in Greenland and in the Urals. Synthetic cryolite
is usually made from NaAlO2, NaHCO3 and NaF.
See the review by Vogel, Chem.
Ztg. 75, 603 (1951).
Properties
Snow-white, semi-opaque masses, vitreous fracture.
Monoclinic crystals with cubic habit, perfect cleavage (001) (110)
(101). The natural form may be colored reddish or brown or even black,
but loses this discoloration on heating. d 2.95. Mohs' hardness 2.5-3. Fuses fairly
easily, mp 1000°.
Sol in concd H2SO4. Dec by boiling with aq
alkali hydroxides or aq calcium hydroxide.Caution
Potential symptoms of overexposure
are irritation of eyes and respiratory system; nausea, abdominal pain,
diarrhea; salivation, thirst and sweating; stiff spine; dermatitis;
calcification of ligaments of ribs and pelvis. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH
97-140, 1997) p 280.