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 054 (OTTO) Lithium fluoride, optical windows, 40 mm dia, 10 mm thick (with Al coated on one face for working wavelength 1550nm) - used to isolate different physical environments while allowing a light beam to pass.