Material Potassium Bromide (KBr)
Potassium Bromide is one of the most useful materials for general purpose spectroscopic windows and applications where sensitivity to moisture is unimportant.
Potassium Bromide is one of the most useful materials for general purpose spectroscopic windows and applications where sensitivity to moisture is unimportant. KBr is the most commonly used beamsplitter material for IR spectrophotometers. Potassium Bromide is used for windows and prisms when transmission through the 0.25 µm - 26 µm range is desired. Potassium Bromide is water soluble and must be protected against moisture degradation of polished surfaces. The material cleaves readily, and can be used at temperatures up to 300 °C. Irradiation of Potassium Bromide produces color centers. Potassium Bromide is produced in large ingots by the Kyropoulos growth method. It cleaves easily. With care it can be polished to a high standard under humidity controlled conditions.
BASE PROPERTIES
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PARAMETER |
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VALUE |
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| OPTICAL |
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Transmission Range |
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0.23 to 25 microns |
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Refractive Index |
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1.52404 (L = 11 microns) |
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Reflection Loss |
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8.4% at 11 µm (2 surfaces) |
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dn/dT |
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-40.83 x 10-6/K |
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dn/dµ = 0 |
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4.2 microns |
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Index of Absorption |
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1.6 x 10-4 cm-1 at 3.8µm |
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| PHYSICAL |
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Density |
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2.753 g/cm3 |
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Melting Point |
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730° C |
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Thermal Conductivity |
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4.816Wm-1K-1 at 319K |
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Thermal Expansion |
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43 x 10-6/К at 300 К |
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Hardness |
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Knoop 7 in <100> with 200g indenter |
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Specific Heat Capacity |
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435 J kg-1K-1 |
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Dielectric Constant |
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4.9 at 1MHz |
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Young's Modulus (E) |
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26.8 GPa |
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Shear Modulus (G) |
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5.08 GPa |
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Bulk Modulus (K) |
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15.03 GPa |
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Elastic Coefficients |
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C11=34.5 MPa, C12=5.4
MPa,
C44=5.08 MPa |
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Apparent Elastic Limit |
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1.1 MPa |
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Poisson Ratio |
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0.203 |
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| CHEMICAL |
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Solubility |
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53.48g/100g water at 273K |
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Molecular Weight |
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119.01 |
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Class/Structure |
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Cubic FCC, NaCl, Fm3m, (100) cleavage |
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REFRACTIVE INDEX
| |
Wavelength, µm |
0.39 |
0.44 |
0.49 |
0.59 |
11.0 |
1.50 |
8.50 |
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| |
Refractive Index |
1.59 |
1.58 |
1.57 |
1.56 |
1.55 |
1.54 |
1.53 |
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Wavelength, µm |
12.0 |
17.0 |
18.1 |
20.5 |
22.0 |
23.9 |
25.2 |
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| |
Refractive Index |
1.52 |
1.51 |
1.50 |
1.49 |
1.48 |
1.47 |
1.46 |
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Delivery
Maximum available size: 140 mm Dia x 30 mm Thk
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