FOR ENQUIRIES
+44(0) 1202 307650
Designed and manufactured in the UK

Caesium Iodide (Cesium Iodide) (CsI)

Caesium Iodide (CsI) Data Sheet     ♦ Caesium Iodide (CsI) MSDS

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

To download this data or our MSDS safety data sheet as a pdf, please click on the links at the top of the page.  To expand the transmission graphs, please click on the image.

Click to access current Caesium Iodide Stock Windows
 

µm   Noµm   Noµm   No
0.5    1.8064 1.0    1.7572 2.0    1.7466
3.0    1.7440 4.0    1.7431 5.0    1.7424
6.0    1.7418 7.0    1.7412 8.0    1.7406
9.0    1.7399 10.0    1.7392 11.0    1.7384
12.0    1.7375 13.0    1.7365 14.0    1.7355
15.0    1.7344 16.0    1.7332 17.0    1.7319
18.0    1.7306 19.0    1.7291 20.0    1.7276
21.0    1.7260 22.0    1.7244 23.0    1.7226
24.0    1.7207 25.0    1.7188 26.0    1.7168
27.0    1.7147 28.0    1.7125 29.0    1.7101
30.0    1.7077 31.0    1.7052 32.0    1.7027
33.0    1.7000 34.0    1.6972 35.0    1.6943
36.0    1.6913 37.0    1.6882 38.0    1.6849
39.0    1.6816 40.0    1.6781 41.0    1.6746
42.0    1.6709 43.0    1.6671 44.0    1.6631
45.0    1.6591 46.0    1.6549 47.0    1.6505
48.0    1.6460 49.0    1.6414 50.0    1.6366

Caesium Iodide is grown by sealed ampoule Stockbarger techniques with ingots of approximately 70mm diameter. CsI is very soft and pliable.

REFERENCES:
(1) Handbook Optical Constants, ed Palik, V2, ISBN 0-12-544422-2
(2) Rodney, J.Opt.Soc.Am. V45, p987, 1955
(3) Combes et al, J.Opt.Soc.Am. V41, p215, 1951
(4) Kelly, Bureau of Mines Bulletin, No371, p51, 1934