.jpg)
Fluorine is a relatively new element in human applications. In ancient times, only minor uses of fluorine-containing minerals existed. The industrial use of fluorite, fluorine's source mineral, was first described by early scientist Georgius Agricola in the 16th century, in the context of smelting. The name fluorite (and later fluorine) derives from Agricola's invented Latin terminology. In the late 18th century, hydrofluoric acid was discovered. By the early 19th century, it was recognized that fluorine was a bound element within compounds, similar to chlorine. Fluorite was determined to be calcium fluoride.
Because of fluorine's tight bonding as well as the toxicity of hydrogen fluoride, the element resisted many attempts to isolate it. In 1886, French chemist Henri Moissan, later a Nobel Prize winner, succeeded in making elemental fluorine by electrolyzing a mixture of potassium fluoride and hydrogen fluoride.
Large-scale production and use of fluorine began during World War 2 as part of the Manhattan Project. Earlier in the century, the main fluorochemicals were commercialized by the DuPont company: refrigerant gases (Freon) and polytetrafluoroethylene plastic (Teflon).
Some instances of ancient use of fluorite, main source mineral of fluorine, for ornamental use carvings exist. However, archeological finds are rare, perhaps in part because of the stone's softness. Two Roman cups made of Persian fluorite have been discovered and are currently exhibited at the British museum. Pliny the Elder described a soft stone from Persia used in cups that may have been fluorite. Fluorite carvings from about 1000 AD have been discovered in the Americas in Indian burial grounds.
The word fluorine derives from the Latin stem of the main source mineral, fluorite, which was first mentioned in 1529 by Georgius Agricola, the father of mineralogy. He described fluorite as a flux -an additive that helps melt ores and slags during smelting.
Fluorite stones were called schone flusse in the German of the time. Agricola, writing in Latin but describing 16th century industry, invented several hundred new Latin terms. For the schone flusse stones, he used the Latin noun fluores, fluxes, because they made metal ores flow when in a fire. After Agricola, the name for the mineral evolved to fluorspar (still commonly used) and then to fluorite.
After 74 years of effort by many chemists, on 26 June 1886, Henri Moissan isolated elemental fluorine. Moissan's report to the French Academy of making fluorine showed appreciation for the feat: One can indeed make various hypotheses on the nature of the liberated gas; the simplest would be that we are in the presence of fluorine.
Moissan's 1887 publication documents reaction attempts of fluorine gas with several substances: sulfur (flames), hydrogen (explosion), carbon (no reaction), etc. Later, Moissan devised a less expensive apparatus for making fluorine: copper equipment coated with copper fluoride.
Moissan also constructed special apparatus -5m long platinum tubes with fluorite windows- to determine the slight yellow color of fluorine gas. The gas appears transparent in small tubes or when allowed to escape. The colour observation was not repeated until the 1980s, when his result was confirmed.
More information: UNT Digital Library
Will fluorine ever have practical applications?
It is very difficult to answer this question.
I may, however, say in all sincerity
that I gave this subject little thought
when I undertook my researches,
and I believe that all the chemists
whose attempts preceded mine gave it
no more consideration.
A scientific research is a search after truth,
and it is only after discovery
that the question of applicability can be usefully considered.
Henri Moisson
No comments:
Post a Comment