Elemental fluorine in Earth’s atmosphere would easily react with atmospheric water vapor, precluding its natural occurrence, it is found only in combined mineral forms, such as: Fluorite (CaF2), Fluorapatite (Ca5(PO4)3F), Cryolite (Na3AlF6).
Fluorides, unlike other halides, are insoluble and do not occur in commercially favorable concentrations in saline waters.
It is lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions.
The most electronegative element, it is extremely reactive. Almost all other elements including some noble gases, form compounds with fluorine.
Industrial synthesis of fluorine gas for uranium enrichment, its largest application.
Fluorine’s first ionization energy is third-highest among all elements, behind helium and neon, which complicates the removal of electrons.
