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
0.27
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
Density
3.2 g/cm3 200 lb/ft3
Dielectric Constant (Relative Permittivity) At 1 MHz
5.2
Light Transmission Range
0.12 to 7.0 µm
Refractive Index
1.4
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