蓝宝石 Sapphire (Al2O3)

Syngony

Tetragon

Symmetry Class

3m

Lattice Constants

a = 4.758 Å

c = 12.991 Å

Cleavability

(1011), (1120) imperfect

Refractive Index at n_e

1.7771

Refractive Index at n_F' - n_C'

0.0107

Thermal Coefficient of Refractive Index at 3.39 microns for ±60 °C

β_o = (0.88 ... 1.28) x 10^-5 β_e = (0.99 ... 1.39) x 10^-5

Spectral Range, microns

0.17 - 5.0

Thermal Linear Expansion, °C^-1 for ±60 °C

⊥ to c-axis

(3.24 ... 5.66) x 10^-6

Thermal Conductivity, W/(m * °C) at 46 °C

⊥ to c-axis

25.2

|| to c-axis

23.1

Specific Heat Capacity, J/(kg * °C)

0.7610 x 10³

Thermal Stability, °C

162 ±8

Melting Point, °C

2030

Density, g/cm³ at 20 °C

3.98

Mohs Hardness

9

Vickers Microhardness, Pa

⊥ to c-axis

2200

|| to c-axis

1940

Constants of Elastic Compliance, Pa^-1

S₁₁ = 2.3 x 10^-12 S₁₂ = -0.7 x 10^-12 S₁₃ = 0.4 x 10^-12 S₃₃ = 2.2 x 10^-12 S₄₄ = -6.8 x 10^-12 S₁₄ = 0.5 x 10^-12

Young Modulus (E), Pa

⊥ to c-axis

46.26 x 10¹⁰

|| to c-axis

42.64 x 10¹⁰

Shear Modulus (G), Pa

⊥ to c-axis

14.43 x 10¹⁰

|| to c-axis

16.29 x 10¹⁰

Poisson Ratio || to c-axis

0.309

Molecular Weight

101.96

Solubility

in water, gram/100 cm³

98 x 10¹⁰

Wavelength, Microns

Refractive Index no

Refractive Index ne

1.0

1.7545

1.7460

2.0

1.7374

1.7299

3.0

1.7015

1.6920

4.0

1.6748

1.6679

Wavelength, Microns

Internal Transmittance

0.2

0.79

0.5

0.97

1.0

0.97

3.0

0.97

5.0

0.45