Fluorine
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a pale yellow diatomic gas. Extremely reactive and highly toxic in its elemental form, fluorine reacts with all other elements except for the light noble gases.
- symbol
- F
- atomic_number
- 9
- discoverer
- Henri Moissan
- element_category
- Halogen
- natural_isotope
- 19F
Lore & Background
Fluorine atoms have nine electrons, one fewer than neon, with an electron configuration of 1s²2s²2p⁵. Its first ionization energy is third-highest among all elements, behind helium and neon, and it has the highest electronegativity of any reactive element. The bond energy of difluorine is much lower than that of Cl₂ or Br₂, accounting for fluorine's easy dissociation and high reactivity. Reactions with metals require varying conditions: alkali metals cause explosions, while most other metals must be powdered to prevent passivation. Hydrogen reacts explosively with fluorine, and even normally unreactive substances like powdered steel, glass fragments, and asbestos fibers react quickly with cold fluorine gas.
Reader's Guide
Fluorine ranks 24th in cosmic abundance and 13th in crustal abundance. Its industrial production for uranium enrichment began during the Manhattan Project in World War II. Owing to the expense of refining pure fluorine, most commercial applications use fluorine compounds: about half of mined fluorite is used in steelmaking, and the rest is converted into hydrogen fluoride or cryolite for aluminium refining. Organofluorine compounds are widely used as refrigerants, electrical insulation, and PTFE (Teflon). The fluoride ion from dissolved fluoride salts inhibits dental cavities and finds use in toothpaste and water fluoridation. Global fluorochemical sales amount to more than US$15 billion a year. Fluorocarbon gases are potent greenhouse gases, with SF₆ having the highest global warming potential of any known substance. Fluorine has no known metabolic role in mammals, but a few plants and marine sponges synthesize organofluorine poisons that help deter predation.
Did You Know?
- Fluorine is the lightest halogen and exists as a pale yellow diatomic gas at standard conditions.
- Several early experimenters died or sustained injuries attempting to isolate fluorine from its compounds.
- Natural fluorine consists entirely of the stable isotope 19F, which is highly suited for NMR and magnetic resonance imaging.
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