Calcium fluoride
Encyclopedia : C : CA : CAL : Calcium fluoride
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General
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| Name | Calcium fluoride |
| Chemical formula | CaF2 |
| Solid state structure (note that this is the same as uranium dioxide) | 
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| SMILES | |
| CAS registry number | 7789-75-5 |
| Appearance | White (or colored by impurities) crystalline solid. |
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Physical properties
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| Formula weight | 78.07 amu |
| Melting point | 1675 K (1402 °C) |
| Boiling point | 2770 K (2500 °C) |
| Density | 3.18 ×103 kg/m3 (solid) |
| Solubility | virtually none in water |
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SI units were used where possible. Unless otherwise stated, standard conditions were used.
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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)
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 optmimizing 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.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.
See also
Related materials
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)
- For a full list of external links to MSDSs, spectroscopic data, commercial chemicals suppliers etc. for this compound, see [Chemical sources].
Suppliers
- [Goodfellow Corporation]
- [Crystan] (UK)
- [Almaz Optics, Inc.] (USA)
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