Calcium fluoride

Disclaimer and references </font> </th></tr> </table> Calcium fluoride (CaF₂) is an insoluble ionic compound of calcium and fluorine. It occurs naturally as the mineral fluorite (also called fluorspar), and it is the source of most of the world's fluorine. It reacts with concentrated sulfuric acid to produce hydrogen fluoride: CaF₂(s) + H₂SO₄(l) → CaSO₄(s) + 2 HF(g)

[edit] Applications

Calcium fluoride is commonly used as a window material for both infrared and ultraviolet wavelengths, since it is transparent in these regions (about 0.15 µm to 9 µm) and exhibits extremely weak birefringence. Nevertheless, at wavelengths as low as 157 nm, which are interesting to semiconductor manufacturers, the birefringence of calcium fluoride exceeds tolerable limits. This may be overcome by minimizing birefringence by optimimizing the growth process. It is particularly important as an ultraviolet optical material for integrated circuit lithography. Canon also uses artificially-crystallized calcium fluoride elements in some of its L-series lenses to reduce light dispersion. As an infrared optical material, calcium fluoride is sometimes known by the Eastman Kodak trademarked name Irtran-3, although this designation is long since obsolete.

Uranium-doped calcium fluoride was the second type of solid state laser invented, in the 1960s. Peter Sorokin and Mirek Stevenson at IBM's laboratories in Yorktown Heights, New York, achieved lasing at 2.5 µm shortly after Maiman's ruby laser.

[edit] See also

• List of laser types
• Photolithography

[edit] Related materials

• Barium fluoride
• Magnesium fluoride
• Calcium chloride

[edit] External links

• NIST webbook thermochemistry data
• Uranium doped CaF₂ laser (pdf file)
• Charles Townes on the history of lasers
• National Pollutant Inventory - Flouride and compounds fact sheet
• MSDS (University of Oxford)

• Link page to external chemical sources.

[edit] Suppliers

• Goodfellow Corporation
• Crystan (UK)
• Almaz Optics, Inc. (USA)de:Kalziumfluorid