Crystallographic
Syngony	Tetragonal
Symmetry Class	4/mmm
Lattice Constants	a = 4.64 Å c = 3.06
Cleavability	(100),(110) perfect

Optical
Refractive Index at ne	1.3786
Refractive Index at nF' - nC'	1.3904
Refractive Index at n10.6	0.0034
Refractive Index at n8.0 - n12.5	0.0110
Thermal Coefficient of Refractive Index at 3.39 microns for ±60 °C	bo = (0.15 ... 0.10) x 10-5 be = (0.15 ... 0.10) x 10-5
Transmission Range, microns	0.13 - 7.0

Thermal
Thermal Linear Expansion, °C-1 for ±60 °C
^ 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 * °C)	0.9200 x 103
Melting Point, °C	1255

Mechanical
Density, g/cm3 at 20 °C	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

Chemical
Molecular Weight	62.32
Solubility
in water, gram/100 cm3	0.0076
in acids	soluble

Ref. Index vs. Wavelength l
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

Internal Transmittance t i (l) vs. Wavelength l
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

Custom sizes and specifications are available on request.