Strontium fluoride
Names | |
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Other names
Strontium difluoride
Strontium(II) fluoride | |
Identifiers | |
3D model (
JSmol ) |
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ChemSpider | |
ECHA InfoCard
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100.029.091 |
EC Number |
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PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
SrF2 | |
Molar mass | 125.62 g/mol |
Density | 4.24 g/cm3 |
Melting point | 1,473 °C (2,683 °F; 1,746 K) |
Boiling point | 2,460 °C (4,460 °F; 2,730 K) |
0.117 g/100 mL | |
Solubility product (Ksp)
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4.33×10−9[1] |
−37.2·10−6 cm3/mol | |
Refractive index (nD)
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1.439 @0.58 μm |
Structure | |
cubic crystal system, cF12 | |
Fm3m, #225 | |
a = 5.80 Å, b = 5.80 Å, c = 5.80 Å α = 90°, β = 90°, γ = 90°
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Sr, 8, cubic F, 4, tetrahedral | |
Hazards | |
Flash point | Non-flammable |
Related compounds | |
Other anions
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Strontium chloride Strontium bromide Strontium iodide |
Other cations
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beryllium fluoride magnesium fluoride calcium fluoride barium fluoride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Strontium fluoride, SrF2, also called strontium difluoride and strontium(II) fluoride, is a fluoride of strontium. It is a brittle white crystalline solid. In nature, it appears as the very rare mineral strontiofluorite.[2][3]
Preparation
Strontium fluoride is prepared by the action of hydrofluoric acid on strontium carbonate.[4]
Structure
The solid adopts the fluorite structure. In the vapour phase the SrF2 molecule is non-linear with an F−Sr−F angle of approximately 120°.[5] This is an exception to VSEPR theory which would predict a linear structure. Ab initio calculations have been cited to propose that contributions from d orbitals in the shell below the valence shell are responsible.[6] Another proposal is that polarization of the electron core of the strontium atom creates an approximately tetrahedral distribution of charge that interacts with the Sr−F bonds.[7]
Properties
It is almost insoluble in water (its
It irritates eyes and skin, and is harmful when inhaled or ingested.
Similar to CaF2 and BaF2, SrF2 displays superionic conductivity at elevated temperatures.[8]
Strontium fluoride is transparent to light in the wavelengths from
Uses
Strontium fluoride is used as an optical material for a small range of special applications, for example, as an optical coating on lenses and also as a thermoluminescent dosimeter crystal.
Another use is as a carrier of
References
- ISBN 978-1138561632.
- ^ "Strontiofluorite".
- ^ "List of Minerals". 21 March 2011.
- ^ W. Kwasnik (1963). "Strontium Fluoride". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY, NY: Academic Press. p. 234.
- ISBN 978-0-08-037941-8.
- doi:10.1063/1.459748
- ^ "Newmet Koch - Strontium". Archived from the original on 2005-12-14.
- ^ Mediatopia Ltd. "Strontium Fluoride (SrF2) Optical Material". Crystran.co.uk. Retrieved 2012-08-18.