锗 Germanium (Ge)

Syngony

Cubic

Symmetry Class

m3m

Lattice Constants

a = 5.657 Å

c = a

Cleavability

(111), perfect

Refractive Index at n_10.6

4.0034

Refractive Index at n8.0 - n_12.5

0.0036

Thermal Coefficient of Refractive Index at 3.39 microns for ±60 ℃

35 - 40 x 10^-5

Transmission Range, microns

2 - 17

Thermal Linear Expansion, ℃_-1 for ±60 ℃

(5.1 ... 5.8) x 10^-6

Thermal Conductivity, W/(m * ℃) at 27 ℃

59.8

Specific Heat Capacity, J/(kg * ℃)

0.310

Melting Point, ℃

937

Absorbance μ(λ) , cm^-1

at 10.6 microns

0.027

Density, g/cm³ at 25 ℃

5.33

Mohs Hardness

6

Vickers Microhardness, Pa

900 x 10⁷

Constants of Elastic Compliance, Pa-1

S11 = 9.69 x 10^-12 S12 = -2.65 x 10^-12

S44 = 14.89  x 10^-12

Young Modulus (E), Pa

in <100> direction

10.32x 10¹⁰

in <111> direction

15.56 x 10¹⁰

Shear Modulus (G), Pa

in <100> direction

6.72 x 10¹⁰

in <111> direction

4.67 x 10¹⁰

Poisson Ratio

0.278

Molecular Weight

72.61

Solubility

in water, gram/100 cm³

insoluble

Wavelength, Microns

Refractive Index

2.0

4.1079

3.0

4.0446

4.0

4.0242

5.0

4.0153

6.0

4.0106

7.0

4.0076

8.0

4.0053

9.0

4.0047

10.0

4.0040

11.0

4.0031

12.0

4.0029

12.5

4.0024

15.0

4.0017

Wavelength, Microns

Internal Transmittance

3.0

0.97

5.0

0.97

6.0

0.97

7.0

0.97

8.0

0.97

9.0

0.97

10.0

0.96

12.0

0.70

15.0

0.56