Cesium Iodide (CsI) Optical Material
Cesium iodide is a non-glass, inorganic optical material. It has a fairly low heat capacity among non-glass optical ceramics. In addition, it has a fairly low thermal conductivity and a moderately low melting temperature. The graph bars on the material properties cards below compare cesium iodide 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
4.0 GPa 0.58 x 106 psi
Knoop Hardness
20
Poisson's Ratio
0.21
Shear Modulus
6.2 GPa 0.9 x 106 psi
Thermal Properties
Melting Onset (Solidus)
620 °C 1150 °F
Specific Heat Capacity
200 J/kg-K 0.048 BTU/lb-°F
Thermal Conductivity
1.1 W/m-K 0.64 BTU/h-ft-°F
Thermal Expansion
48 µm/m-K
Otherwise Unclassified Properties
Density
4.5 g/cm3 280 lb/ft3
Light Transmission Range
0.25 to 55 µm
Refractive Index
1.9
Common Calculations
Stiffness to Weight: Axial
0.49 points
Stiffness to Weight: Bending
12 points
Thermal Diffusivity
1.2 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