Stories About Chemistry
12. The “Omnivorous”
That is what the prominent Soviet scientist A. E. Fersman called it. For the world knows no element more ferocious, nature has produced no substance chemically more active than the main character of this story.
You will never find it in nature in the native state, but only in the form of compounds. Its English name is fluorine from the Latin fluo meaning “flow”. But its Russian name ftor is derived from the Greek for “destructive.” This is a second, no less forceful term characterizing the main feature of this representative of the seventh group of the Mendeleyev Table.
It has been said that “the path to free fluorine led through human tragedy.” These are not just fine words. Man has discovered 104 elements. In the hunt for new simple substances researchers overcame a multitude of difficulties, knew many disappointments, became the victims of curious errors.
The pursuit of traces of unknown elements has cost scientists a great deal of effort. Fluorine, the element fluorine in its free form, has cost lives.
Long is the doleful list of casualties incurred in attempts to obtain free fluorine. Knox, a member of the Irish Academy of Science, the French chemist Niklesse, the Belgian researcher Layette, all fell victim to the “omnivorous.” And many more scientists suffered severe injuries.
Among them were the prominent French chemists GayLussac and Thénard and the English chemist Humphry Davy. There were no doubt also unknown investigators on whom fluorine took revenge for insolent attempts to isolate it from its compounds.
When on June 28, 1886, Henri Moissan reported to the Paris Academy of Science that he had finally succeeded in obtaining free fluorine, he had a black bandage over one of his eyes.
The French scientist Moissan was the first to find out what the element fluorine was like in the free state. And it must be owned that many chemists were afraid to work with this element.
Twentieth-century scientists have found methods of bridling the fury of fluorine, have hunted out ways of making it serve mankind. The chemistry of this elements has now become a large independent field of inorganic chemistry. The terrible “genius” of the bottle has been subdued. And the efforts of the numerous fighters for free fluorine have been well repaid.
Many types of modern refrigerators use freon as their cooling agent. Chemists have a more complex name for this substance: difluorodichloromethane. Fluorine is an indispensable constituent of this compound. Itself “destructive,” fluorine can form compounds which practically nothing can destroy. They will not burn nor rot and are insoluble in alkalis and acids; free fluorine does not attack them, and they are almost wholly indifferent to arctic cold and to sudden sharp temperature changes. Some of them are liquids, others solids.
Their common name is fluorocarbons, compounds which nature herself was unable to invent. They were produced by man. The union of carbon and fluorine was found very useful. Fluorocarbons are employed as cooling fluids in motors, for impregnating special fabrics, as very long-lived lubricants, insulators and structural materials for various kinds of equipment in the chemical industry.
When the scientists were searching for ways of harnessing nuclear energy, it became necessary to separate the uranium isotopes uranium235 and uranium-238. And as has already been said above, investigators succeeded in accomplishing this very complicated task with the aid of a very interesting compound called uranium hexafluoride.
It was fluorine which helped chemists to prove that the inert gases were not at all chemical sloths as had been thought for decades. The first compound of the inert gas xenon brought to life was its compound with fluorine. Such is fluorine’s work record.