Fluorine Reduction

Fluorine is a chemical element with symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. As the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.
Among the elements, fluorine ranks 24th in universal abundance and 13th in terrestrial abundance. Fluorite, the primary mineral source of fluorine, was first described in 1529; as it was added to metal ores to lower their melting points for smelting, the Latin verb fluo meaning “flow” became associated with it. Fluorine was first isolated using low-temperature electrolysis, a process still employed for modern production. Industrial production of fluorine gas for uranium enrichment, its largest application, began during the Manhattan Project in World War II.
Fluorine is never found uncombined and forms hydrofluoric acid when mixed with water.

Fluoride is deliberately added to most potable water supplies in the USA to help prevent dental carries (cavities). Although low concentration protect, higher concentration cause unsightly mottling. The USA MCL for fluoride is 4 mg/L.

Hydrofluoric acid is poorly ionized compared to other strong acids such as hydrochloric, nitric, sulfuric, etc. Very dangerous to handle due to extreme toxicity and adsorption thru the skin. Forms the fluorosilicic anion when sufficient silica is present. Etches glass and can diffuse through some plastics.