5531. Lithium Fluoride

Nomenclature

CAS number: 7789-24-4
FLi; mol wt 25.94.
F 73.24%, Li 26.76%.
LiF.

Description and references

Prepd from LiOH and HF or by dissolving Li2CO3 in excess HF, evaporating to dryness, and heating to red heat: v. Wartenberg, Schultz, Z. Elektrochem. 27, 568 (1921); Kwasnik in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 235. Review of toxicology of fluoride compounds: G. L. Waldbott, Acta Med. Scand. Suppl. 400, 1-44 (1963).

Properties

Cubic crystals (NaCl lattice) or white fluffy powder. d20 2.640. mp 848°; bp 1681°. Volatilizes at 1100-1200°. Soly in water (25°): 0.13 g/100 ml. Soluble in acids. With hydrofluoric acid it forms lithium bifluoride, LiHF2. With lithium hydroxide it forms a double salt LiF.LiOH, mp 462°. LD in guinea pigs (mg/kg): 200 orally, 2000 s.c. (Waldbott).

Use

As flux for soldering and welding aluminum, in the manuf of vitreous enamels and glazes. Lithium fluoride prisms are used in infrared spectrophotometers.