H. H. Li. Refractive index of alkali halides and its wavelength and temperature derivatives. J. Phys. Chem. Ref. Data5, 329-528 (1976) and references therein. * Sellmeier formula derivation is based on a single data point and knowledge of the dielectric constants and the characteristic absorption peaks.
Lithium chloride (LiCl) is a salt with a range of applications, from hygroscopic uses in air conditioning and industrial drying to a role as a brazing flux for aluminum in metallurgy. In the realm of optics, lithium chloride is employed as a crystal for IR, THz, and far-IR spectroscopy. It has a broad transmission range and is relatively inert, making it useful for specialized applications that require transparency in those wavelength ranges. However, it is highly hygroscopic and must be carefully handled and stored to maintain its optical properties.