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fluoride,a salt of hydrofluoric acid; see hydrogen fluoridehydrogen fluoride,
chemical compound, HF, a colorless, fuming liquid or colorless gas that boils at 19.54°C;. It is miscible with water and is soluble in benzene, toluene, and concentrated sulfuric acid.
..... Click the link for more information. . See also fluoridationfluoridation
, process of adding a fluoride to the water supply of a community to preserve the teeth of the inhabitants. Tooth enamel ordinarily contains small amounts of fluorides and when the amount is augmented through the intake of fluoridated water, especially during the
..... Click the link for more information. ; fluorinefluorine
, gaseous chemical element; symbol F; at. no. 9; at. wt. 18.9984; m.p. −219.6°C;; b.p. −188.14°C;; density 1.696 grams per liter at STP; valence −1. Fluorine is a yellowish, poisonous, highly corrosive gas.
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a compound of fluorine with other elements. The fluorides of elements in Groups I and II of Mendeleev’s periodic system are solids with an ionic element—fluorine bond; the fluorides of most elements in Groups VI–VII are gases with a covalent element—fluorine bond. Compounds containing a C—F bond form numerous classes of fluorocarbons; the higher fluorides of many metals, such as U, V, Mo, W, and Re, are volatile substances. Fluorides occur in nature as constituents of minerals. In terms of chemical properties, the fluorides of halogens, inert gases, oxygen, nitrogen, and many other elements in higher oxidation states (for example, PtF5, CoF3, and AgF2) are oxidizing agents; the fluorides of arsenic, antimony, and boron are strong Lewis acids (seeACIDS AND BASES).
Fluorides can be obtained by the interaction of fluorine with elements, by the action of hydrogen fluoride on metals, and by other methods.
Hydrogen fluoride, oxyfluorides, and nitrogen fluorine compounds are widely used. The chlorine fluorides C1F3 and C1F5 are rocket-fuel oxidizing agents; C1F3 also serves as a fluorinating agent in the preparation of uranium hexafluoride, UF6, which is used in the atomic industry for the isotope separation of uranium. The volatile fluorides of metals are used in the application of metallic coatings. The fluorides of lithium, magnesium, calcium, strontium, barium, and other metals are used as raw materials in the manufacture of optical glass. (See alsoCRYOLITE.)
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A. V. PANKRATOV