Materials Chart

Click on a material to see it's properties
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Chart Key:

1.  SWL-  Highest wavenumber for which transmission is greater than 50% for 1mm thickness

2.  LWL-  Lowest wavenumbers for which transmission is greater than 50% for 1mm thickness and 4 mm thickness

3.  RI-  Refractive index at indicated wavelength in microns

4.  S/D-  Scratch and dig surface polish achievable with normal polishing techniques.  High quality UV-Vis optics are usually 20/10 and IR optics 40/20.  Each level is approximately 2 times worse than the lower numbers.

5.  Flatness-  Routine polishing can yield flatness as measured in wavelengths of 6328Å (HeNe laser).  1 wave flat or better generally  required for high quality optical components such as lenses and beamsplitters

6.  Pe-  Yield strength in atmospheres for a 25 mm x 1 mm thick window with
a safety factor of 4.  To calculate thickness required for a given pressure                     

7.    GRAS-  US FDA Generally Recognized As Safe, may be used to measure food products.

8.    *-  UV grade material required to achieve this limit

9.   Restrahlen-  Frequencies at which the materials exhibit high resonance reflection.  Apparent in reflection measurements

10.  BBAR Coat-  Coating on material to increase energy transmission and/or reduce interference fringing.  Number is the approximate gain in signal per window.

11.  Hard Coat-  Coating to increase abrasion resistance and/or humidity and chemical resistance.  Number is the approximate increase in abrasion, humidity or chemical resistance.

fp  =  Flash point

Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

AgBr

22000

255

292

2.22@10

80/50

5

0.56

88

6.5

1.2E-05

432

7

N

N
Comments: Insoluble in water, slightly soluble in sodium hydroxide and some amines.  Migrates into base metals.  Will blacken under UV radiation. Cold flows and should not be used above 200°C.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

AgCl

24500

353

404

1.90@10

80/50

5

0.56

123

5.6

5.2E-02

457

10

N

N
Comments: Insoluble in water, slightly soluble in sodium hydroxide and some amines.  Migrates into base metals.  Will blacken under UV radiation. Cold flows and should not be used above 200°C.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

AI2O3

40000

1608

1834

1.76@0.6

1.77@0.6

40/20

l/2

6.1

741

4.0

0

2040

1370

Y

1.05

N
Comments: GRAS.  Resistant to strong acids and bases.  Bi-refringent.  Very durable and may be used at high temperatures.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

AMTIR

11000

593

625

2.50@10

80/50

l

0.27

  

4.4

0

370

170

Y

1.3

Y

2
Comments: Amorphous Material which Transmits Infrared Radiation. A chalcogenide glass which although relatively hard is also brittle. Insoluble in water and resistant to acids, it is attacked by alkalis.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

BaF2

66600*

691

782

1.45@5

40/20

l/20

0.56

213

4.9

0.17

1280

82

N

Y

3
Comments: A hard  material suitable for higher pressure applications, it is extremely vulnerable to thermal shock. Almost insoluble in water, it should not be used with ammonium hydroxide, ammonium salts, complex agents such as EDTA, and acids.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

CaF2

79500*

896

1025

1.40@5

40/20

l/20

0.77

286

3.2

0.0017

1360

158

N

Y

3
Comments: A very hard material similar to BaF2, but less water soluble. Still vulnerable to thermal shock and attacked by nitric acid and strong hydroxides, ammonium salts, complexing reagents such as EDTA.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

CdTe

17000

313

340

2.67@10

80/50

l

0.12

  

6.2

0

1092

45

Y

1.35

Y

2
Comments: A hard but brittle material, CdTe is insoluble in water but is attacked by HNO3.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

Cleartran

22000

690

722

2.2@10

40/20

l/20

2.2

328

4.1

0

1830

240

Y

1.25

Y

2
Comments: GRAS. A water-clear form of ZnS. Properties similar to ZnS.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

CsI

42000

172

1.73@10

80/50

l/10

0.12

69

4.5

44

621

20

N

Y

6
Comments: Soft and hygroscopic, CsI is generally selected for its far-IR cut-off.  Should only be exposed to anhydrous solvents; must not be used with lower alcohols or aqueous solutions. Can react with many organic compounds.  A hard optical coating can help protect the surface from humidity.  In powdered form can be used to make pellets.  Store CsI in a desiccator or a heated cabinet.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

Diamond

30000

< 2

2.41@0.6

20/10

l

10.9

None

3.5

0

550fp

5700

Y

1.25

N
Comments: GRAS. Hard and chemically resistant, the Type IIA diamond is often chosen for high pressure applications. Due to its high intrinsic value, diamonds sizes are typically between 1 and 9mm. Has a characteristic absorption doublet between 1800 & 2700 cm-1.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

Ge

5500

432

574

4.00@10

60/40

l/8

1.0

None

5.3

0

936

780

Y

2.0

Y

2
Comments: Hard and very brittle, germanium is temperature sensitive. Loses transmission when heated; material becomes optically opaque at about 190C.  Attacked by hot H2SO4 and aqua regia. Because of it's high RI, it suffers from large reflection losses; these can be reduced by an anti-reflection coating.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

KBr

48800

345

388

1.52@10

60/40

l/20

0.02

129

2.8

53

730

6

N

Y

4
Comments: Probably the most popular material used in IR spectroscopy, KBr is hygroscopic and must be used with anhydrous solvents. It withstands thermal and mechanical shock well, but must not be used with aqueous samples, glycerol and the lower alcohols. A hard optical coating can provide additional protection from humidity. In powdered form can be used to make pellets.  Store KBr in a desiccator or a heated cabinet.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

KCl

55600

385

439

1.45@10

60/40

l/20

0.05

158

2.0

35

776

7

N

Y

4
Comments: Hygroscopic and must be used with anhydrous solvents.  It withstands thermal and mechanical shock well, but must not be used with lower molecular weight alcohols.  A hard optical coating can provide additional protection from humidity.  When anti-reflection coated, is a good CO2 laser window.  Store KCl in a desiccator or a heated cabinet.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

KRS-5

17900

204

232

2.37@10

60/40

l/1

0.56

74

7.4

0.05

414.5

40

Y

1.2

Y

2
Comments: Extremely toxic, even by skin contact, KRS-5 should be handled with gloves or finger cots. A soft material, it cold flows and deforms under pressure, and this process is enhanced above 200C. It is attacked by complexing agents, and is slightly water soluble.  Because of its high toxicity, KRS-5 should be re-polished professionally.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

LiF

96150*

1105

1286

1.39@0.5

40/20

l/10

0.23

400

2.6

0.27

870

105

N

Y

2
Comments: Slightly water soluble, LiF is a hard, brittle material.  Should not be employed over 400°C; this material is sensitive to thermal shock.
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Material

SWL

cm-1

LWL

cm-1

RI

S/D

Flatness

Pe

atm

Restrahlen

cm-1

Density

gm/cc

Solubility

g/100g

Melting

Point °C

Hardness

kg/mm2

BBAR
Coat

Hard
Coat

MgF2

90900*

1271

1457

1.38@0.5

1.39@0.5

40/20

l/20

1.0

500

3.2

0.0002

1255

415

N

Y

2
Comments: Almost insoluble in water, MgF2 is a hard material suited to relatively high pressure applications. Bi-refringent, and subject to thermal shock.  MgF2 should not be used above 500°C.
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Material