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Calcium Fluoride is used for optical windows, lenses and prisms in transmision range 0.15-9mkm. Degradation due to to moisture in the atmosphere is minimal, and polished surfaces of the CaF2 windows may be expected to withstand several years exposure to normal atmospheric conditions.
Since they are nonaxial, CaF2 crystals do not require consideration of axial direction. Because of CaF2 low refractive index, Calcium Fluoride windows can be used without an anti-reflection coating.
Calcium Fluoride is attacked by atmospheric
moisture at
Typical applications: VUV - UV - IR imaging systems, excimer laser windows, Spectroscopic windows and lenses.
Chemical Formula |
CaF2 |
Crystal Class |
Cubic, cleaves [111] plane |
Lattice Constant, Å |
5.46 |
Density, g/cm3 ( |
3.18 |
Molecular Weight |
78.08 |
Dielectric Constant for 105 Hz |
6.76 |
Melting Temperature, K |
1630 |
Thermal Conductivity, W/(m K) at 273 K |
10 |
Thermal Expansion, 1/K at 300 K |
18.9 x 10-6 |
Specific Heat, cal/(g K) at 273 K |
0.204 |
Debye Temperature, K |
510 |
Young's Modulus, GPa |
75.79 |
Rupture Modulus, GPa |
0.0365 |
Shear Modulus, GPa |
33.76 |
Bulk Modulus, GPa |
83.03 |
Poisson's Ratio |
0.28 |
Knoop Hardness, kg/mm2 |
178 [100], 160 [110] |
µm |
No |
µm |
No |
µm |
No |
0.149 |
1.5800 |
0.161 |
1.5490 |
0.195 |
1.5000 |
0.200 |
1.4950 |
0.222 |
1.4800 |
0.248 |
1.4680 |
0.266 |
1.4621 |
0.280 |
1.4584 |
0.300 |
1.454 |
0.337 |
1.4481 |
0.400 |
1.4419 |
0.486 |
1.4370 |
0.588 |
1.4339 |
0.656 |
1.4325 |
0.687 |
1.4320 |
0.728 |
1.4314 |
0.884 |
1.4298 |
1.014 |
1.4288 |
1.100 |
1.4283 |
1.250 |
1.4275 |
1.650 |
1.4256 |
1.900 |
1.4244 |
2.058 |
1.4236 |
2.450 |
1.4214 |
2.700 |
1.4199 |
2.800 |
1.4192 |
3.050 |
1.4175 |
3.400 |
1.4149 |
4.000 |
1.4096 |
4.400 |
1.4057 |
4.800 |
1.4014 |
5.000 |
1.3991 |
5.304 |
1.3952 |
5.893 |
1.3871 |
6.483 |
1.3782 |
7.072 |
1.3681 |
7.661 |
1.357 |
8.251 |
1.3444 |
8.840 |
1.3308 |
9.429 |
1.3161 |
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