Caesium Iodide - CsI
lenses, windows, mirrors, filters and prisms
Click here to download PDF version of this page.Caesium Iodide is a very useful material with a transmission range from the visible region out to 70 microns through to a 2mm thick window. CsI is very soft and water-soluble and when humidity is relatively high polished surfaces may be damaged by moisture in the atmosphere. Principally used for Infrared Spectroscopic windows and also for beam splitters in FTIR Instumentation. CsI is also available thallium doped for scintillation applications.
| Transmission Range | 0.25 – 55 microns |
| Crystal Structure | Caesium chloride |
| Cleavage Plane | None |
| Colour | Colourless |
| Density | 4.526 |
| Melting Point (°) | 621 |
| Reflection Loss | 13.6% (10µ) for 2 surfaces |
| Solubility index | 44gm/100gm / 0°C |
| Hardness (Knoop) | 20/200 gm indenter |
| Thermal Conductivity (cal/cm sec°C) | 0.13 Wm-1°K-1 |
| Thermal Expansion coefficient (/°C) | 50x10-6 (25-50°C) |
Whilst every effort has been made to verify the data provided, no responsibility can be accepted for its accuracy