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Lithium Fluoride (LiF) Optical Material

Lithium fluoride is a non-glass, inorganic optical material. It has the highest heat capacity and a fairly low density among non-glass optical ceramics. The graph bars on the material properties cards below compare lithium fluoride to other non-glass optical ceramics (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

120 GPa 17 x 106 psi

Poisson's Ratio


Shear Modulus

52 GPa 7.5 x 106 psi

Thermal Properties

Melting Onset (Solidus)

870 °C 1600 °F

Specific Heat Capacity

1560 J/kg-K 0.37 BTU/lb-°F

Thermal Conductivity

12 W/m-K 6.9 BTU/h-ft-°F

Thermal Expansion

32 µm/m-K

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz


Electrical Dissipation At 1 MHz


Otherwise Unclassified Properties


2.6 g/cm3 160 lb/ft3

Light Transmission Range

0.12 to 6.5 µm

Refractive Index


Common Calculations

Stiffness to Weight: Axial

24 points

Stiffness to Weight: Bending

62 points

Thermal Diffusivity

2.9 mm2/s

Followup Questions

Further Reading

Handbook of Optical Materials, Marvin J. Weber, 2003

Handbook of Optical Constants of Solids, Edward D. Palik (editor), 1998

Ceramics and Composites: Processing Methods, Narottam P. Bansal and Aldo R. Boccaccini (editors), 2012