 Occurrence
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| Fluorine in the form of fluorspar (also called fluorite) (calcium fluoride) was described in 1530 by Georgius Agricola for its use as a flux, which is a substance that is used to promote
the fusion of metals or minerals. In 1670 Schwanhard found that glass was etched when it was exposed to fluorspar that was
treated with acid. Karl Wilhelm Scheele and many later researchers, including Humphry Davy, Gay-Lussac, Antoine Lavoisier, and Louis Thenard all would experiment with hydrofluoric acid, easily obtained by treating
calcium fluoride (fluorspar) with concentrated sulfuric acid.
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| It was eventually realized that hydrofluoric acid contained a previously unknown element. This element was not isolated for
many years after this, due to its extreme reactivity; fluorine can only be prepared from its compounds electrolytically, and
then it immediately attacks any susceptible materials in the area. Finally, in 1886, elemental fluorine was isolated by Henri
Moissan after almost 74 years of continuous effort by other chemists. It was an effort which cost several researchers their
health or even their lives. The derivation of elemental fluorine from hydrofluoric acid is exceptionally dangerous, killing
or blinding several scientists who attempted early experiments on this halogen. These men came to be referred to as "fluorine martyrs." For Moissan, it earned him the 1906 Nobel Prize in chemistry (Moissan
himself lived to be 54, and it is not clear whether his fluorine work shortened his life).
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| The first large-scale production of fluorine was needed for the atomic bomb Manhattan project in World War II where the compound
uranium hexafluoride (UF6) was needed as a gaseous carrier of uranium to separate the 235U and 238U isotopes of uranium. Today both the gaseous diffusion process and the gas centrifuge process use gaseous UF6 to produce enriched uranium for nuclear power applications. In the Manhattan Project, it was found that elemental fluorine was present whenever UF6 was, due to the spontaneous decomposition of this compound into UF4 and F2. The corrosion problem due to the F2 was eventually solved by electrolytically coating all UF6 carrying piping with nickel metal, which resists fluorine's attack. Joints and flexible parts were made from Teflon, then a very recently-discovered
fluorine-containing plastic which was not attacked by F2.
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