氟化镁 Magnesium Fluoride (MgF2)

Syngony

Tetragonal

Symmetry Class

4/mmm

Lattice Constants

a = 4.64 Å

c = 3.06

Cleavability

(100),(110) perfect

Refractive Index at n_e

1.3786

Refractive Index at n_F' - n_C'

1.3904

Refractive Index at n_10.6

0.0034

Refractive Index at n_8.0 - n_12.5

0.0110

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

β_o = (0.15 ... 0.10) x 10^-5

β_e = (0.15 ... 0.10) x 10^-5

Transmission Range, microns

0.13 - 7.0

Thermal Linear Expansion, ℃-1 for ±60 ℃

⊥ to c-axis

(6.23 ... 9.25) x 10^-6

|| to c-axis

(10.86 ... 14.54) x 10^-6

Specific Heat Capacity, J/(kg * ℃)

0.9200 x 10³

Melting Point, ℃

1255

Density, g/cm³ at 20 ℃

3.18

Mohs Hardness

6

Vickers Microhardness, Pa

⊥ to c-axis

441 x 10⁷

|| to c-axis

289 x 10⁷

Constants of Elastic Compliance, Pa^-1

S11 = 12.45 x 10^-12 S12 = -7.16 x 10^-12

S13 = -1.66 x 10^-12 S33 = 5.94 x 10^-12

S44 = 17.54 x 10^-12 S66 = 10.53 x 10^-12

Young Modulus (E), Pa

⊥ to c-axis

16.91 x 10¹⁰

|| to c-axis

7.97 x 10¹⁰

Shear Modulus (G), Pa

⊥ to c-axis

5.71 x 10¹⁰

|| to c-axis

9.52 x 10¹⁰

Poisson Ratio

|| to c-axis

0.577

Molecular Weight

62.32

Solubility

in water, gram/100 cm³

0.0076

in acids

soluble

Wavelength, Microns

Refractive Index no

Refractive Index ne

0.2

1.4231

1.4367

0.5

1.3797

1.3916

1.0

1.3736

1.3852

2.0

1.3686

1.3797

3.0

1.3618

1.3724

4.0

1.3525

1.3622

5.0

1.3400

1.3487

6.0

1.3242

1.3315

7.0

1.3044

1.3101

Wavelength, Microns

Internal Transmittance

0.2

0.95

0.5

0.97

1.0

0.97

3.0

0.97

5.0

0.97

6.0

0.91

7.0

0.54

8.0

0.12