Lithium Fluoride ( LiF ) - Properties and Applications

Lithium Fluoride (LiF) has the lowest refractive index of all common infrared materials. It also possesses the highest UV transmission of any material, being able to transmit significantly into the VUV region at the hydrogen Lyman-alpha line (121nm).

It is slightly soluble in water, while being soluble in HDF and other acids. However, it can be cleaned with alcohol.


Lithium fluoride is most widely used as a flux in the production of ceramics, such as enamels, glasses and glazes. Similarly it is also used in brazing and welding fluxes and molten salt chemistry in metallurgy.

It is also used for:

        X-Ray monochromator plates as an analysis crystal

        Heat sink materials

        UV transmission windows

Key Properties

Property Value
Density (g/cm3) 6.51
Melting Point (°C) 2310
Co-Efficient of Thermal Expansion (x10-6 /°C) 37
Dielectric Constant 9.1
Young’s Modulus (GPa) 64.8
Refractive Index at 1.0µm 1.38711



  1. Mesfin Getachew Mesfin Getachew Poland says:

    Can ask you please the appropriate thickness of LiF crystal used for  X-ray contact microscopy application?

  2. maha Alzaak maha Alzaak U.A.E. says:

    what is the chemical and physical properties of lithium fluoride ?

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