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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.
The fluorine–fluorine bond of the difluorine molecule is relatively weak when compared to the bonds of heavier dihalogen molecules. The bond energy is significantly weaker than those of Cl 2 or Br 2 molecules and similar to the easily cleaved oxygen–oxygen bonds of peroxides or nitrogen–nitrogen bonds of hydrazines. [8]
At a given temperature and pressure, a substance with high volatility is more likely to exist as a vapour, while a substance with low volatility is more likely to be a liquid or solid. Volatility can also describe the tendency of a vapor to condense into a liquid or solid; less volatile substances will more readily condense from a vapor than ...
Boiling-point elevation is the phenomenon whereby the boiling point of a liquid (a solvent) will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent. This happens whenever a non-volatile solute, such as a salt, is added to a pure solvent, such as water.
Fluoride volatility is the tendency of highly fluorinated molecules to vaporize at comparatively low temperatures. Heptafluorides, hexafluorides and pentafluorides have much lower boiling points than the lower-valence fluorides. Most difluorides and trifluorides have high boiling points, while most tetrafluorides and monofluorides fall in
Hydrogen fluoride does not boil until 20 °C in contrast to the heavier hydrogen halides, which boil between −85 °C (−120 °F) and −35 °C (−30 °F). [ 6 ] [ 7 ] [ 8 ] This hydrogen bonding between HF molecules gives rise to high viscosity in the liquid phase and lower than expected pressure in the gas phase.
The solid state of fluorine relies on Van der Waals forces to hold molecules together, [citation needed] which, because of the small size of the fluorine molecules, are relatively weak. Consequently, the solid state of fluorine is more similar to that of oxygen [6] [7] or the noble gases than to those of the heavier halogens. [citation needed]
The total atmospheric concentration of F-gases, CFCs, and HCFCs has grown rapidly since the mid-twentieth century; a time which marks the start of their production and use at industrial scale. As a group in year 2019, these unnatural man-made gases are responsible for about one-tenth of the direct radiative forcing from all long-lived ...