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Cesium Iodide is used for prisms and cell windows in the infrared out to 50mkm. Its refractive index ranges from about 1.8 to 1.6 in its useful transmission range from 0.5 to 50mkm. Cesium Iodide is highly soluble in water and must be protected from moisture.
This material is relatively soft, does not cleave and can withstand shock and rapid temperature changes.
Caesium Iodide (Cesium Iodide) is the material with the deepest known IR transmission, and is sometimes used for components in the widest range spectrophotometers. An extremely soft material, Caesium Iodide is extremely difficult to polish, and so performance is compromised for range. Doped with Thallium, CsI(Tl) is a useful scintillator which emits at a wavelength that is a good match for Silicon photodiodes. Arrays of Caesium Iodide are used in security imaging systems.
| Transmission Range : |
0.25 to 55 μm (1) |
| Refractive Index : |
1.73916 at 10 μm (1)(2) |
| Reflection Loss : |
13.6% at 10 μm |
| Absorption Coefficient : |
n/a |
| Reststrahlen Peak : |
145.8 μm |
| dn/dT : |
-99.3 x 10-6 /°C (2) |
| dn/dμ = 0 : |
6 μm |
| Density : |
4.51 g/cc |
| Melting Point : |
621 °C |
| Thermal Conductivity : |
1.1 W m-1 K-1 at 298 K (3) |
| Thermal Expansion : |
48.3 x 10-6 /°C at 293 K (3) |
| Hardness : |
Knoop 20 with 200g indenter |
| Specific Heat Capacity : |
201 J Kg-1 K-1 (4) |
| Dielectric Constant : |
5.65 at 1 MHz |
| Youngs Modulus (E) : |
5.3 GPa |
| Shear Modulus (G) : |
6.24 GPa |
| Bulk Modulus (K) : |
12.67 GPa |
| Elastic Coefficients : |
C11=24.6 C126.7 C44=6.24 |
| Apparent Elastic Limit : |
5.6 MPa (810psi) |
| Poisson Ratio : |
0.214 |
| Solubility : |
44 g/100 g water at 0 °C |
| Molecular Weight : |
259.83 |
| Class/Structure : |
Cubic CsCl, Pm3m, no cleavage, deforms |
|
Wavelength, µm |
0.29 |
0.32 |
0.35 |
0.39 |
0.46 |
0.52 |
0.64 |
0.92 |
9.0 |
24.4 |
33.0 |
39.5 |
44.7 |
49.3 |
|
Refractive Index |
1.98 |
1.94 |
1.90 |
1.86 |
1.82 |
1.80 |
1.78 |
1.76 |
1.74 |
1.72 |
1.70 |
1.68 |
1.66 |
1.64 |
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