Refractive index database

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Optical constants of NaCl (Sodium chloride)
Li 1976: n 0.20–30 µm

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula [ i ]



297 K (24 °C).


H. H. Li. Refractive index of alkali halides and its wavelength and temperature derivatives. J. Phys. Chem. Ref. Data 5, 329-528 (1976) and references therein.
* Sellmeier formula is derived by critical analysis of experimental data from several sources.


[Expressions for n]   [CSV - comma separated]   [TXT - tab separated]   [Full database record]


Sodium chloride, NaCl

Sodium chloride (NaCl), commonly known as table salt, is a white crystalline compound. In its purified form, it is transparent and can be shaped into clear optical windows. With its wide transparency range that extends from the ultraviolet through to the infrared spectrum, NaCl finds significant utility in the optics field. It's particularly well-suited for infrared spectroscopy. However, being hygroscopic, it readily absorbs moisture from the air, which can degrade its optical performance. Thus, careful handling and storage are essential when using it for optical applications.

Other names

  • Salt
  • Common salt
  • Table salt
  • Rock salt


  • Halite

External links