fluorine

Fluorine is the chemical element with the symbol F and the atomic number 9. It is the lightest halogen, the most electronegative element, and the most reactive of all elements. At room temperature it is a pale yellow diatomic gas (F2) with a boiling point of −188.1°C. Fluorine forms compounds with almost all other elements; its chemistry is dominated by the strong attraction of the fluorine atom for electrons, making many fluorides highly stable and many reactions fiercely exothermic. In nature, fluorine occurs only in minerals, most commonly as fluoride ions in fluorite (CaF2) and related minerals. Free fluorine gas is not found in nature and is produced industrially.

Industry obtains fluorine by the electrolysis of molten salts containing fluorine, typically a mixture of hydrogen fluoride (HF) and potassium fluoride (KF). The process requires highly corrosion-resistant equipment and stringent safety controls due to the gas’s reactivity and toxicity.

Fluorine forms hydrogen fluoride (HF) and a wide range of metal fluorides. Organofluorine compounds are widespread, including refrigerants, solvents, agrochemicals, and pharmaceuticals. Fluorine is essential in the manufacture of uranium hexafluoride (UF6) for uranium enrichment, and fluoropolymers such as polytetrafluoroethylene (PTFE, Teflon).

Safety: Fluorine gas is extremely reactive and toxic; exposure can cause severe respiratory, ocular, and dermal injuries. Hydrogen fluoride, when dissolved in water to form HF, is highly corrosive and penetrates tissue, and exposures require immediate medical treatment, including calcium gluconate for skin or eye burns.