Fluorine

Fluorine, ₉F

Liquid fluorine (F2 at extremely low temperature)
Fluorine
Pronunciation	/ˈflʊəriːn/ /ˈflɔːriːn/ (FLOR-een)
Allotropes	alpha, beta (see Allotropes of fluorine)
Appearance	gas: very pale yellow liquid: bright yellow solid: alpha is opaque, beta is transparent
Standard atomic weight Ar°(F)
	18.998403162±0.000000005[1] 18.998±0.001 (abridged)[2]
Fluorine in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson – ↑ F ↓ Cl oxygen ← fluorine → neon
Atomic number (Z)	9
Group	group 17 (halogens)
Period	period 2
Block	p-block
Electron configuration	[He] 2s2 2p5[3]
Electrons per shell	2, 7
Physical properties
Phase at STP	gas
Melting point	(F2) 53.48 K ​(−219.67 °C, ​−363.41 °F)[4]
Boiling point	(F2) 85.03 K ​(−188.11 °C, ​−306.60 °F)[4]
Density (at STP)	1.696 g/L[5]
when liquid (at b.p.)	1.505 g/cm3[6]
Triple point	53.48 K, ​.252 kPa[7]
Critical point	144.41 K, 5.1724 MPa[4]
Heat of vaporization	6.51 kJ/mol[5]
Molar heat capacity	Cp: 31 J/(mol·K)[6] (at 21.1 °C) Cv: 23 J/(mol·K)[6] (at 21.1 °C)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 38 44 50 58 69 85
Atomic properties
Oxidation states	common: −1
Electronegativity	Pauling scale: 3.98[3]
Ionization energies	1st: 1681 kJ/mol 2nd: 3374 kJ/mol 3rd: 6147 kJ/mol (more)[8]
Covalent radius	64 pm[9]
Van der Waals radius	135 pm[10]
Spectral lines of fluorine
Other properties
Natural occurrence	primordial
Crystal structure	​cubic
Thermal conductivity	0.02591 W/(m⋅K)[11]
Magnetic ordering	diamagnetic (−1.2×10−4)[12][13]
CAS Number	7782-41-4[3]
History
Naming	after the mineral fluorite, itself named after Latin fluo (to flow, in smelting)
Discovery	André-Marie Ampère (1810)
First isolation	Henri Moissan[3] (June 26, 1886)
Named by	Humphry Davy André-Marie Ampère
Isotopes of fluorine v e
Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct 18F trace 109.734 min β+ 18O 19F 100% stable [14]
Category: Fluorine view talk edit | references

Fluorine is a chemical element; it has symbol F and atomic number 9. It is the lightest halogen^{[note 1]} and exists at standard conditions as pale yellow diatomic gas. Fluorine is extremely reactive as it reacts with all other elements except for the light inert gases. It is highly toxic.

Among the elements, fluorine ranks 24th in cosmic abundance and 13th in crustal abundance. Fluorite, the primary mineral source of fluorine, which gave the element its name, was first described in 1529; as it was added to metal ores to lower their melting points for smelting, the Latin verb fluo meaning 'to flow' gave the mineral its name. Proposed as an element in 1810, fluorine proved difficult and dangerous to separate from its compounds, and several early experimenters died or sustained injuries from their attempts. Only in 1886 did French chemist Henri Moissan isolate elemental fluorine using low-temperature electrolysis, a process still employed for modern production. Industrial production of fluorine gas for uranium enrichment, its largest application, began during the Manhattan Project in World War II.

Owing to the expense of refining pure fluorine, most commercial applications use fluorine compounds, with about half of mined fluorite used in steelmaking. The rest of the fluorite is converted into hydrogen fluoride en route to various organic fluorides, or into cryolite, which plays a key role in aluminium refining. The carbon–fluorine bond is usually very stable. Organofluorine compounds are widely used as refrigerants, electrical insulation, and PTFE (Teflon). Pharmaceuticals such as atorvastatin and fluoxetine contain C−F bonds. The fluoride ion from dissolved fluoride salts inhibits dental cavities and so finds use in toothpaste and water fluoridation. Global fluorochemical sales amount to more than US$15 billion a year.

Fluorocarbon gases are generally greenhouse gases with global-warming potentials 100 to 23,500 times that of carbon dioxide, and SF₆ has the highest global warming potential of any known substance. Organofluorine compounds often persist in the environment due to the strength of the carbon–fluorine bond. Fluorine has no known metabolic role in mammals; a few plants and marine sponges synthesize organofluorine poisons (most often monofluoroacetates) that help deter predation.^[15]

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