Fluorine

Fluorine - F

CAS: 7782-41-4
Description: Pale yellow, corrosive gas
Classification:Halogen
Date of Discovery: 1886
Discoverer: Joseph Henri Moissan
Name Origin: Latin fluo, "flow"

Atomic Number: 9
Number of Neutrons: 10
Atomic Mass: 18.9984032(9) amu
Melting Point: -219.62 °C
Boiling Point: -188.12 °C
Density (0 °C, 1 atm): 1.696 g/cm³;
liquid at b.p. - 1.50 g/cm³
Atomic volume: 17.1 cm³/mol
Electrical resistivity:
Thermal conductivity: 0.000279 W/cmK
Enthalpy of atomization: 79.08 kJ/mol
Enthalpy of vaporization: 3.2698 kJ/mol
Enthalpy of fusion: 0.2552 kJ/mol
Specific heat capacity: 0.82 J/gK

Energy levels: 2-7
Electron configuration: [He]2s²2p⁵
Crystal Structure: Cubic
Atomic radius: 0.57 Å
Covalent radius: 0.72 Å
Oxidation States: -1
Electronegativity, Pauling: 3.98
Electron affinity: 3.401190 eV
First ionization energy: 17.422 eV
2nd ionization energy: 34.97 eV
3rd ionization energy: 62.707 eV
Polarizability: 0.557 10^-24cm³

Isotope	Natural Abundance	Atomic Mass	Half-life	Decay Mode	Spin
¹⁵F	15.0180	5 x 10^-22 s	p	(1/2-)
¹⁶F	16.01147	1 x 10^-20 s	p	0-
¹⁷F	17.0020952	64.5 s	⁺	5/2+
¹⁸F	18.000938	1.830 h	^{+, EC}	1+
¹⁹F	100.	18.9984032	Stable	1/2+
²⁰F	19.9999813	11.0 s	^-	2+
²¹F	20.999949	4.16 s	^-	5/2+
²²F	22.00300	4.23 s	^-	4+
²³F	23.00357	2.2 s	^-	5/2+
²⁴F	24.0081	0.3 s	^-
²⁵F	25.0121	0.06 s
²⁶F	26.0196	0.03 s
²⁷F	27.0269
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 1886 by Moisson after nearly 74 years of continuous effort. Fluorine occurs chiefly influor-spar (CaF₂) and cryolite (Na₂AlF₂), but is rather widely distributed in other minerals. It is a member of the halogen family of elements, and is obtained by electrolyzing a solution of potassium hydrogen fluoride in anhydrous hydrogen fluoride in a vessel of metal or transparent fluorspar. Modern commercial production methods are essentially variations on the procedures first used by Moisson. Fluorine is the most electronegative and reactive of all elements. It is a pale yellow, corrosive gas, which reacts with practically all 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 atom bomb project and nuclear energy applications, however, made it necessary to produce large quantities. Safe handling techniques have now been developed and it is possible at present to transport liquid fluorine by the ton. Fluorine 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 is extensively used for etching the glass of light bulbs, etc. Fluorochloro hydrocarbons are extensively used in air conditioning and refrigeration. It has been suggested that fluorine can be substituted for hydrogen wherever it occurs in organic compounds, which could lead to an astronomical number of new fluorine compounds. 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 said to be beneficial and used in water supplies to prevent dental cavities. Elemental fluorine has been studied as a rocket propellant as it has an exceptionally high specific impulse value. Compounds of fluorine with rare gases have now been confirmed. Fluorides of xenon, radon, and krypton are among those known. Elemental 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. Fluorine is known to have thirteen isotopes. LINKS: ATSDR ToxFAQ's - Fluorides, Hydrogen Fluoride, and Fluorine Fluorides and Fluoridation Fluorine Diffusion Dating Techniques Fluorine Specifications How do fluorocarbons destroy the ozone layer? Return Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998.

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