| Transmission Range | 0.15 to 11 μm |
| Refractive Index | 1.439 at 0.55 μm (1) |
| Reflection Loss | 6.3% at 0.55 μm (2 surfaces) |
| Absorption Coefficient | <1 x 10-3 cm-1 @ 5 μm |
| Reststrahlen Peak | 46 μm |
| dn/dT | -12 x 10-6 K-1 |
| dn/dμ | n/a |
| Density | 4.24 g/cc |
| Melting Point | 1450°C |
| Thermal Conductivity | 8.3 W m-1 K-1 @ 293 K (2) |
| Thermal Expansion | 18.4 x 10-6/°C @ 293 K |
| Hardness | Knoop 154 (100) & 140 (110) |
| Specific Heat Capacity | 543 J Kg-1 K-1 |
| Dielectric Constant | 7.69 at 2 MHz |
| Young's Modulus (E) | 89.1 GPa |
| Shear Modulus (G) | 34.6 GPa |
| Bulk Modulus (K) | 24.65 GPa |
| Elastic Coefficients | C11 = 124; C12 = 45; C44 = 31.7 |
| Apparent Elastic Limit | 36.5 MPa (5300 psi) |
| Poisson Ratio | 0.25 |
| Solubility | 0.012 g/100 g water at 27°C |
| Molecular Weight | 125.62 |
| Class/Structure | Cubic Fm3m (#225), cleaves on (111) |
| μm | No | μm | No | μm | No |
|---|---|---|---|---|---|
| 0.15 | 1.594 | 0.91 | 1.43343 | 7.01 | 1.37308 |
| 0.20 | 1.504 | 1.01 | 1.43269 | 8.01 | 1.35362 |
| 0.31 | 1.45725 | 1.51 | 1.43003 | 8.10 | 1.3517 |
| 0.41 | 1.44556 | 2.01 | 1.42761 | 8.60 | 1.3405 |
| 0.51 | 1.44029 | 3.01 | 1.42159 | 9.10 | 1.3283 |
| 0.61 | 1.43740 | 4.01 | 1.41337 | 9.60 | 1.3151 |
| 0.71 | 1.43560 | 5.01 | 1.40269 | 10.6 | 1.2854 |
| 0.81 | 1.43435 | 6.01 | 1.38934 | 11.1 | 1.2686 |
Strontium fluoride is produced by the vacuum Stockbarger growth technique.
REFERENCES:
(1) Handbook of Optical Constants, ed Palik, V3, ISBN 0-12-544423-0
(2) For Thermal Conductivity (Tc) a figure of 1.42 W/(mK) is in wide circuation but is plainly incorrect based on observation of UKRI STFC (2019) plus logically the Tc should be intermediate between BaF2 and CaF2. OSTI.GOV gives (p44) 0.016 cal cm-1 s C-1 for 25°C which converts to 6.7 W m-1 K-1. OSA PUBLISHING confirms (p95) our existing Tc for CaF2 as 9.71W m-1K-1 and offers for SrF2 as 8.3 W m-1 K-1