Atomic number: 9

Symbol: F

Category: Non-metal - Halogen

Density at 25°C: gas, but 1.3 denser than air.

Fluorine is the first of a group (period) category called halogens. These are all very reactive elements as you follow them down the periodic table. They are so reactive that F even as F2 is very reactive.


Liquid fluorine below -188°C, just to be safe. image: wikipedia

Use, natural applications or common combinations: 

  • mostly present in minerals like fluorite
  •  Polytetrafluoroethylene (Teflon) is the most common fluoropolymer
  • Around half of all mined fluorite is used directly in steel-making.

Basic characteristics:

  • Standard atomic weight: 18.998 4032(5)
  • Melting point: −219.62 °C
  • Boiling point: −188.12 °C
  • Radioactivity: almost all stable
    • 19F is stable but 18F only has a half life of 109minutes