Fluorine is a very reactive element and is incredibly dangerous in its pure state. The gas is pale yellow. Moreover, it reacts with all kinds of materials, bricks, glass and steel, piercing them directly. Because it is so dangerous, in its pure state it is stored in containers made of nickel that can withstand its attack. Minerals such as cryolite and fluorspar contain this element. This gas and its less harmful compounds have a wide variety of uses. Hydrofluoric acid, HF, is a toxic liquid used to etch patterns on glass. Some glazes used to coat ceramics contain fluorine minerals. When heated, these glazes release fluorine, which hardens the ceramic. Another derivative, polytetrafluoroethylene (PTFE), is commonly used to make nonstick pans. Also, PTFE fibers are used to make lightweight, waterproof clothing. One of the most common uses of fluorine compounds is as an additive in toothpaste, as it hardens teeth and prevents tooth decay.

Summary of properties (F)

Atomic weight18.998403163(6)
Discoverer (year)Moissan, Henri (1886)
Natural formgas (F2)
Electron configuration[He] 2s2 2p5
Melting point (ºC)-220
Boiling point (ºC)-188
Abundance in earth's crust (ppm)585
Isotope (abundance)19F (100))
Density g/cm31.7
Van der Waals radius (pm)147
Covalent radius (pm)60
Electronegativity (Pauling)3.98
Vaporization enthalpy (kJ/mol)6.62
Enthalpy of fusion (kJ/mol)0.51
Specific heat capacity (J/g·K) at 25ºC and 1 atm0.82
Thermal conductivity (W/cm·K) at 25ºC and 1 atm<0.001 (F2)
Oxidation state-1
Electron affinity (eV)3.40
1st Ionization potential (eV)17.4228

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