Crystallographic Ge ( Germanium )
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Syngony
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Cubic
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Symmetry Class
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m3m
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Lattice Constants, Angstroms
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a=5.657 c=a
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Cleavability
|
(111), non-perfect
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Refractive Index at n10.6
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4.0034
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Refractive Index, n8.0-n12.5
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0.0036
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Thermal Coefficient of Refractive Index at l=3.39 microns, îÑ-1
for +/-60îÑ
|
(35.0¸40.0)• 10-5
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Transmission Range, microns (thickness 10ìì)
|
1.8¸17
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Transmittance ti(l) vs. wavelength l
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Ge ( Germanium )
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Internal Transmittance ti(l) vs.
wavelength l
Ge ( Germanium )
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l,ìêì
|
ti(l)
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3.0
|
0.97
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|
5.0
|
0.97
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6.0
|
0.97
|
|
7.0
|
0.97
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|
8.0
|
0.97
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|
9.0
|
0.97
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|
10.0
|
0.96
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12.0
|
0.70
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15.0
|
0.56
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20.0
|
0.05
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|
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Refractive Index n vs.
wavelength l
Ge ( Germanium )
|
|
l,ìêì
|
n(l)
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|
2.0
|
4.1079
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3.0
|
4.0446
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4.0
|
4.0242
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5.0
|
4.0153
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6.0
|
4.0106
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7.0
|
4.0076
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8.0
|
4.0053
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9.0
|
4.0047
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10.0
|
4.0040
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11.0
|
4.0031
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12.0
|
4.0029
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12.5
|
4.0024
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15.0
|
4.0017
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Thermal Linear Expansion at, îÑ-1 for +/-60îÑ
|
(5.1¸5.8)• 10-6
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Thermal Conductivity, W/(m • îÑ) at 27 îÑ
|
59.8
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|
Specific Heat Capacity, J/(kg • îÑ) for 20¸100 îÑ
|
309.8
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Melting Point, îÑ
|
937
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Mechanical Ge ( Germanium )
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Density, g/cm3 at 20 îÑ
|
5.33
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Mohs Hardness
|
6
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Vickers Microhardness , Pa
|
900• 107
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Constants of Elastic Compliance, Pa-1
|
S11
|
9.69• 10-12
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S12
|
-2.65• 10-12
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S44
|
14.89• 10-12
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Poisson Ratio
|
0.278
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Young Modulus (Å), Pa
|
<100>
|
10.32• 1010
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|
<100>
|
15.56• 1010
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Shear Modulus (G), Pa
|
(100)
|
4.67• 1010
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(100)
|
6.72• 1010
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Chemical Ge ( Germanium )
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Solubility Ge
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|
in water at 20 îÑ
g/100cm3
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in acids
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insoluble
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soluble
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"Opto-Technological Laboratory" produces lenses, windows, prisms, wedges, ball lenses, cylindrical lenses and others optical components according to customers’ specifications and drawings out of crystals germanium ( Ge ) . |
