Absolute Indices of Refraction List, Index of Refraction of Various Materials
Index of refraction of any material is strongly dependent on the wavelength (frequency) of light used to measure it. Standard index of refraction measurements are taken at the "yellow doublet" sodium D line, with a wavelength of 589 nanometers (509 THz).
Material
Index of Refraction
State
Vacuum
1
(by definition)
Helium
1.000036
Gas
(0°C and 1 atm)
Hydrogen
1.000132
Gas
(0°C and 1 atm)
Air
1.000277
Gas
(at STP*)
Air
1.000293
Gas
(0°C and 1 atm)
Carbon Dioxide
1.001
Gas
(0°C and 1 atm)
Liquid Helium
1.025
Liquid
(at -270°C)
Water Ice
1.31
Solid
(at 0°C)
Water
1.330
Liquid
(at 20°C)
Acetone
1.36
Liquid
(at 20°C)
Ethanol
1.361
Liquid
(at 20°C)
Kerosene
1.39
Liquid
(at 20°C)
Corn Oil
1.47
Liquid
(at 20°C)
Glycerol
1.4729
Liquid
(at 20°C)
Acrylic Glass
1.490–1.492
Solid
(at 20°C)
Benzene
1.501
Liquid
(at 20°C)
Crown Glass (pure)
1.50–1.54
Solid
(at 20°C)
Plate Glass (window glass)
1.52
Solid
(at 20°C)
Sodium Chloride (table salt)
1.544
Solid
(at 20°C)
Amber
1.55
Solid
(at 20°C)
Polycabonate
1.60
Solid
(at 20°C)
Flint Glass (pure)
1.60–1.62
Solid
(at 20°C)
Bromine
1.661
Liquid
(at 20°C)
Sapphire
1.762–1.778
Solid
(at 20°C)
Cubic Zirconia
2.15–2.18
Solid
(at 20°C)
Diamond
2.417
Solid
(at 20°C)
Silicon
3.42–3.48
Solid
(at 20°C)
Germanium
4.05–4.01
Solid
(at 20°C)
*STP is defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 105 Pa (100 kPa, 1 bar).
'Physics is mathematical not because we know so much about the physical world, but because we know so little; it is only its mathematical properties that we can discover.'