Difficulties in isolating 'Fluorine'

What is 'Fluorine' ?

The element Fluorine is a pale greenish-yellow gas. It occures naturally within some fluorite crystals.

Difficulties in isolating Fluorine

The main difficulty in isolating Fluorine was that it reacted with any element it came in contact with. Hence, when isolating it with electrolysis, it reacted with the electrodes itself. The french chemist, Ferdinand Frederic Henri Moissan found a solution to this by experimenting with different elements, alloys and minerals.

His work was interrupted 4 times because of Fluorine poisoning. Eventually he found, electrodes made from an alloy of platinum and iridium. These were sealed into a platinum U-tube closed with caps made from the mineral fluorspar, the caps being covered with a layer of gum-lac. The U-tube was chilled to -10°F to reduce the rate of the action of the fluorine on the platinum.

An account of his experiments of 1886:

"I obtained the fluorine from a fluorine compound that had been added to a mineral having a low melting point and in which the fluorine compound dissolved readily. The use of electricity produced the fluorine at the positive terminal. Difficulty was experienced in getting any material for that terminal that would resist the chemical action of the gas. After some failures, and four interruptions of work caused by severe poisoning, the following arrangement of apparatus proved fairly satisfactory. Two electrodes were made from an alloy of platinum and iridium. These were sealed into a platinum U-tube closed with caps made from the mineral fluorspar, the caps being covered with a layer of gum-lac. The U-tube was chilled to 10 degrees below zero Fahrenheit to reduce the rate of the action of the fluorine on the platinum. The first test made with the gas was to bring it in contact with the element silicon. There was an immediate burst of flame, a gaseous product being formed."

Ferdinand Frederic Henri Moissan died, aged 55, in 1907; a year after recieving the Nobel prize for chemistry.

Other Fluorine chemists :
Humphrey Davy of England: poisoned, recovered.
George and Thomas Knox of Ireland: both poisoned, one bedridden 3 years, recovered.
P. Louyet of Belgium: poisoned, died.
Jerome Nickels of Nancy, France: poisoned, died.
George Gore of England: fluorine / hydrogen explosion, narrowly escaped injury.
Henri Moissan of France: poisoned several times, success, but shortened lifespan.

Source : LateralScience - Web Archive
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