Lithium fluoride is an inorganic compound with the chemical formula LiF. It is a colorless solid, that transitions to white with decreasing crystal size. Although odorless, lithium fluoride has a bitter-saline taste. Its structure is analogous to that of sodium chloride, but it is much less soluble in water
LW 045 (OTTO) Lithium fluoride, optical windows, 40 mm dia, 5 mm thick - used to isolate different physical environments while allowing a light beam to pass.