Almaz Optics, Inc.
12 Chadsford Ct.  Marlton, NJ 08053, USA
Tel:  856 797-0491, Fax: 856 797-0228
e-mail: mail@almazoptics.com

 

LITHIUM FLUORIDE LiF

Lithium Fluoride is used for windows, prisms, and lenses in the vacuum UV, UV, visible and infrared where desired transmission is in the 0.104 µm - 7 µm range. Modest precautions should be taken against moisture and high energy radiation damage. LiF is attacked by atmospheric moisture at 400 °C and softens at 600 °C. LiF is sensitive to thermal shock. Irradiation produces color centers. The material can be cleaved. VUV grade is available.
Maximum available size: 100 mm Dia x 40 mm Thk.



Main Properties

Chemical Formula LiF
Crystal Class Cubic
Lattice Constant, Å 4.03
Molecular Weight 25.94
Density, g/cm3 (20 °C) 2.60
Reflection Loss, % for two surfaces at 4 µm 4.4
Dielectric Constant for 102-1010 Hz at 298 K 9.0
Melting Temperature, K 1140
Thermal Conductivity, W/(m K) at 314 K 11.3
Thermal Expansion, 1/K at 300 K 34.4 x 10-6
Specific Heat, cal/(g K) at 283 K 0.37
Debye Temperature, K 732
Bandgap, eV 13.6
Solubility, g/100 g H2O at 291 K 0.27
Knoop Hardness, kg/mm2 100
Young's Modulus, GPa 64.77
Apparent Elastic Limit, MPa 11.2
Shear Modulus, GPa 55.12
Bulk Modulus, GPa 62.0
Poisson Ratio 0.326

Refractive Index

Wavelength, µm 0.20 0.22 0.24 0.29 0.39 0.60 1.75 2.75 3.40
Refractive Index 1.44 1.43 1.42 1.41 1.40 1.39 1.38 1.37 1.36