|Molar mass||62.3018 g/mol|
|Appearance||white tetragonal crystals|
|Melting point||1,263 °C (2,305 °F; 1,536 K)|
|Boiling point||2,260 °C (4,100 °F; 2,530 K)|
|0.013 g/100 mL|
Solubility product (Ksp)
|Solubility||soluble in nitric acid
insoluble in ethanol
Refractive index (nD)
|Crystal structure||Rutile (tetragonal), tP6|
|Space group||P42/mnm, No. 136|
Std enthalpy of
Gibbs free energy (ΔfG˚)
LD50 (Median lethal dose)
|2330 (rat, oral)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is: / ?)(|
Magnesium fluoride is an inorganic compound with the formula MgF2. The compound is a white crystalline salt and is transparent over a wide range of wavelengths, with commercial uses in optics that are also used in space telescopes. It occurs naturally as the rare mineral sellaite.
Production and structure
- MgO + (NH4)HF2 → MgF2 + NH3 + H2O
Related metathesis reactions are also feasible.
Magnesium fluoride is transparent over an extremely wide range of wavelengths. Windows, lenses, and prisms made of this material can be used over the entire range of wavelengths from 0.120 μm (vacuum ultraviolet) to 8.0 μm (infrared). High quality synthetic VUV grade MgF2 is quite expensive, in the region of $3000/kg (2007) but the real cost of optics in this material is due to relatively low volume manufacture. However, with lithium fluoride it is one of the two materials that will transmit in the vacuum ultraviolet range at 121 nm (Lyman alpha) and this is where it finds its application. Lower grade MgF2 is sometimes used in the infrared but here it is inferior to calcium fluoride. MgF2 is tough and works and polishes well, but it is slightly birefringent and should be cut with the optic axis perpendicular to the plane of the window or lens.
- Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, FL: CRC Press, pp. 4–67; 1363, ISBN 0-8493-0594-2
- Aigueperse, Jean; Paul Mollard, Didier Devilliers, Marius Chemla, Robert Faron, Renée Romano, Jean Pierre Cuer (2005), "Fluorine Compounds, Inorganic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a11_307
- J. Chem. Soc., Faraday Trans., 1996, 92, 2753 - 2757. doi:10.1039/FT9969202753
- A java applet showing the effect of MgF2 on a lens
- Infrared windows at Lawrence Berkeley National Laboratory
- National Pollutant Inventory - Fluoride and compounds fact sheet
- Crystran Data Crystran MSDS