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| Atomic Number: | 9 | Atomic Symbol: | F | | Atomic Weight: | 18.999840 | Electron Configuration: | 2-7 | | Shells: | 2,7 | Filling Orbital: | 2p5 | | Melting Point: | -219.62oC | Boiling Point: | -188.14oC | | Uses: | Toothpaste, refrigerant and other chloroflurocarbons (CFC) |
History(L. and F. fluere, flow or flux) In 1529, Georigius Agricola
described the use of fluorspar as a flux, and as early as 1670 Schwandhard found
that glass was etched when exposed to fluorspar treated with acid. Scheele and
many later investigators, including Davy, Gay-Lussac, Lavoisier, and Thenard,
experimented with hydrofluoric acid, some experiments ending in tragedy.
The element was finally isolated in 1866 by Henry Moissan of France after
nearly 74 years of continuous effort.
PropertiesFluorine is the most electronegative and reactive of all
elements. It is a pale yellow, corrosive gas, which reacts with most organic and
inorganic substances. Finely divided metals, glass, ceramics, carbon, and even
water burn in fluorine with a bright flame.
Until World War II, there was no commercial production of elemental fluorine.
The nuclear bomb project and nuclear energy applications, however, made it
necessary to produce large quantities.
UsesFluorine and its compounds are used in producing uranium (from the
hexafluoride) and more than 100 commercial fluorochemicals, including many well
known high-temperature plastics. Hydrofluoric acid etches the glass of light
bulbs, etc. Fluorochlorohydrocarbons are extensively used in air conditioning
and refrigeration.
The presence of fluorine as a soluble fluoride in drinking water to the
extent of 2 ppm may cause mottled enamel in teeth, when used by children
acquiring permanent teeth; in smaller amounts, however, fluorides are added to
water supplies to prevent dental cavities.
Elemental fluorine has been studied as a rocket propellant as it has an
exceptionally high specific impulse value.
CompoundsOne hypothesis says that fluorine can be substituted for
hydrogen wherever it occurs in organic compounds, which could lead to an
astronomical number of new fluorine compounds. Compounds of fluorine with rare
gases have now been confirmed in fluorides of xenon, radon, and krypton.
HandlingElemental fluorine and the fluoride ion are highly toxic. The
free element has a characteristic pungent odor, detectable in concentrations as
low as 20 ppb, which is below the safe working level. The recommended maximum
allowable concentration for a daily 8-hour time-weighted exposure is 1 ppm.
Safe handling techniques enable the transport liquid fluorine by the ton.
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