Caesium Iodide


The material with the deepest known IR transmission, CsI is often used for components in wide range spectrophotometers. A soft material that is rugged and shock resistant, slightly hydroscopic. Doped with thallium, CsI(Tl) is a useful scintillator.


Apparent Elastic Limit (MPa): 5.6
Bulk Modulus (K) (GPa): 12.67
Cleavage Planes: None
Density ( 4.51
Dielectric Constant: 5.65 at 1MHz
Elastic Coefficient C11: 24.6
Elastic Coefficient C12: 6.7
Elastic Coefficient C44: 6.24
Hardness (knoop): 20
Melting Point (K): 894
Poisson Ratio: 0.214
Reflection Loss (%): 13.6 at 10µ
Refractive Index: 1.74 at 10µ
Restrahlen Peak (µ): 145.8
Shear Modulus (G) (GPa): 6.24
Solubility (g/100g H2O): 44.0 at 273K
Specific Heat Capacity (J·kg·m-1·K-1): 201
Stability: Slightly Hygroscopic
Structure: Cubic
Thermal Conductivity (W·m-1·K-1): 1.1 at 298K
Youngs Modulus (E) (GPa): 5.3
Thermal Expansion (K-1 at 300K): 48.3x10-6
Transmission Range (µ): 0.25-55.0