Lithium fluoride
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| Names | |
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IUPAC name
Lithium fluoride
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| Identifiers | |
7789-24-4 
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| 3D model (Jmol) | Interactive image |
| ChemSpider |
23007
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| ECHA InfoCard | 100.029.229 |
| EC Number | 232-152-0 |
| PubChem | 224478 |
| RTECS number | OJ6125000 |
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| Properties | |
| LiF | |
| Molar mass | 25.939(2) g/mol |
| Appearance | white powder or transparent crystals, non-hygroscopic |
| Density | 2.635 g/cm3 |
| Melting point | 845 °C (1,553 °F; 1,118 K) |
| Boiling point | 1,676 °C (3,049 °F; 1,949 K) |
| 0.27 g/100 mL (18 °C) 0.134 g/100 mL (25 °C) |
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| Solubility | soluble in HF insoluble in alcohol |
| −10.1·10−6 cm3/mol | |
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Refractive index (nD)
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1.3915 |
| Structure | |
| Cubic | |
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a = 403.51 pm
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| Linear | |
| Thermochemistry | |
| 1.604 J/(g K) | |
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Std molar
entropy (S |
1.376 J/(g K) |
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Std enthalpy of
formation (ΔfH |
-616 kJ/mol |
| Hazards | |
| NFPA 704 | |
| Lethal dose or concentration (LD, LC): | |
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LD50 (median dose)
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143 mg/kg (oral, rat) |
| Related compounds | |
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Other anions
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Lithium chloride Lithium bromide Lithium iodide Lithium astatide |
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Other cations
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Sodium fluoride Potassium fluoride Rubidium fluoride Caesium fluoride Francium fluoride |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is  ?) |
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| Infobox references | |
Lithium fluoride is an inorganic compound with the chemical formula LiF. It is a colorless solid, that transitions to white with decreasing crystal size. Although odorless, lithium fluoride has a bitter-saline taste. Its structure is analogous to that of sodium chloride, but it is much less soluble in water. It is mainly used as a component of molten salts. Formation of LiF releases one of the highest energy per mass of reactants, only second to that of BeO.
LiF is prepared from lithium hydroxide and hydrogen fluoride or by dissolving lithium carbonate in excess hydrogen fluoride, evaporating to dryness and heating to red hot.
Fluorine is produced by the electrolysis of molten potassium bifluoride. This electrolysis proceeds more efficiently when the electrolyte contains a few percent of LiF, possibly because it facilitates formation of Li-C-F interface on the carbon electrodes. A useful molten salt, FLiNaK, consists of a mixture of LiF, together with sodium fluoride and potassium fluoride. The primary coolant for the Molten-Salt Reactor Experiment was FLiBe; LiF-BeF2 (66-33 mol%).
Because of its large band gap, LiF crystals are transparent to short wavelength ultraviolet radiation, more so than any other material. LiF is therefore used in specialized UV optics, (See also magnesium fluoride). Lithium fluoride is used also as a diffracting crystal in X-ray spectrometry.
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