Barium fluorid ( BaF2 )

Crystal properties   Barium fluorid
Crystal Type. cubic, CaF2 type structure
Transmission Range 0.15 ... 15 µm
Refractive Index no = 1,6654
ne = 1,4898 @ 509 nm
Density 4.89 g/cm3
Melting Point 1280, 1355 °C  
Molecular Weight 175.3368  
Thermal Conductivity 11.72 W/(m K) @ 13 °C  
Specific Heat 410 J/(kg K) @ 27 °C  
Thermal Expansion 18.1 × 10–6 / K @ –110...120 °C  
Hardness (Knoop) 82 (indenter load: 500 g)  
Young’s Modulus 56.4 GPa  
Shear Modulus 25.4 GPa  
Bulk Modulus 268.89 GPa  
Rupture Modulus 26.2 Mpa  
Elastic Coefficient C11 = 90.4  
C12 = 40.6    
C44 = 25.3 Gpa    
Dielectric Constant 7.33 @ f = 2 MHz  
Solubility in Water 0.17 g / 100 g @ 23 °C  
Crystal Structure single crystal, synthetic  
Cleavage Planes (111)  
Application Scintillation material
correction part in lens systems
 
Remarks radiation resistant
susceptible to thermal shock
laser damage threshold: 27,5 GW/cm2,
@ 3.8 µm, 75 ns pulse length
 
List of Optical Crystals
Materials TDRefractive Index TDTransmission
Range (mm)
Density
(g/cm³)
TDThermal Expansion 
Coefficient (10-6/K) 
BK7 glass 1.5164 (588 nm) 0.330 – 2.1 2.51 7.5 
SF11 glass 1.78472 (588 nm) 0.370 – 2.5 4.74 6.8 
F2 glass 1.62004 (588 nm) 0.420 – 2.0 3.61 8.2 
Fused Silica 1.4858 (308 nm) 0.185 – 2.5 2.20 0.55 
CaF2 1.399 (5.0 mm) 0.170 – 7.8 3.18 8.85 
BaF2 1.460 (3.0 um) 0.15 – 12.0 4.88 18.4 
Sapphire 1.755 (1.0mm) 0.180 – 4.5 3.98 8.4 
Silicon 3.4179 (10mm) 1.200 – 7.0 2.33 4.15 
Ge 4.003 (10 mm) 1.900 – 16 5.33 6.1 
ZnSe 2.40  (10 mm) 0.630 – 18 5.27 7.8 
ZnS 2.2 (10mm) 0.380 –14 4.09 6.5 
LiF 1.39 (500 nm) [0.150 – 5.2 2.64 37 
KBr 1.526 (10 mm) [0.280 – 22 2.75 43 
MgF2 no = 1.3836 
ne = 1.3957 (405 nm)
0.130 – 7.0 7.37 a: 13.7
b: 8.48
YVO4 no = 1.9500
ne = 2.1554 (1.3 mm)
0.400 – 5.0 4.22 a: 4.46
b: 11.37
Calcite no = 1.6557
ne = 1.4852 (633 nm)
0.210 – 2.3 2.75 a: 24.39
b: 5.68
Quartz no = 1.5427
ne = 1.5518 (633 nm)
0.200 – 2.3 2.65 7.07
α-BBO no = 1.6749
ne = 1.5555 (532 nm)
0.190 – 3.5 3.85 a: 4.0
c: 36
LiNbO3 no = 2.2863
ne = 2.2027 (633 nm)
0.370 – 4.5 4.64 a: 16.7
c: 2.0