Noun
lithium fluoride (uncountable)
(inorganic chemistry) A salt that may be prepared by the action of hydrofluoric acid on many lithium compounds, occurring naturally as griceite; its crystals are used in optical instruments, and in radiation dosimetry (based on its radiothermoluminescence).
Lithium fluoride is exceptionally chemically stable and LiF-BeF 2 mixtures have low melting points. Source: Internet