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Magnesium Fluoride (MgF2) Optical Material

Magnesium fluoride is a non-glass, inorganic optical material. It has a fairly high heat capacity and a fairly high thermal conductivity among non-glass optical ceramics. The graph bars on the material properties cards below compare magnesium 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

130 GPa 18 x 106 psi

Poisson's Ratio


Shear Modulus

76 GPa 11 x 106 psi

Thermal Properties

Melting Onset (Solidus)

1260 °C 2300 °F

Specific Heat Capacity

980 J/kg-K 0.23 BTU/lb-°F

Thermal Conductivity

28 W/m-K 16 BTU/h-ft-°F

Thermal Expansion

11 µm/m-K

Other Material Properties


3.2 g/cm3 200 lb/ft3

Dielectric Constant (Relative Permittivity) At 1 MHz


Light Transmission Range

0.12 to 7.0 µm

Refractive Index


Common Calculations

Stiffness to Weight: Axial

22 points

Stiffness to Weight: Bending

52 points

Thermal Diffusivity

8.8 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