How 1970s deodorant is still doing harm
By Laurence Knight
Fluorine is an evil gas. And it is also used to manufacture a string of other artificial gases, some of which nearly left mankind exposed to burning ultraviolet light - and are even now warming the planet.
"Fluorine is the tyrannosaurus rex of the periodic table," says chemistry professor Andrea Sella. "It will react spontaneously with every other element except for helium, neon and argon."
If you ever happen to lay eyes on pure, elemental fluorine, it looks fairly innocuous - a pale yellow gas - but in truth it is so dangerous that Sella's department at University College London does not even keep it in stock.
It produces a smell similar to chlorine, he says, "but generally, if you smell fluorine what you do is run away as fast as you can".
Sella does have a jar of another frightening material - hydrofluoric acid or HF. Its acidity - that is, the reactiveness of the hydrogen ions it contains - is not actually quite as strong as that of the better known hydrochloric or sulphuric acids.
But it is nonetheless an exceptionally vicious chemical, because the ferocious fluorine ions can penetrate deep into your body. "It's an unbelievably painful burn, and one that you cannot really treat, because it's gone inside," says Sella.
Once inside, the fluoride gobbles up the body's calcium, which can lead to heart failure in extreme cases.
HF's corrosiveness does have its uses, such as etching glass or microchip circuitry. Yet this noxious acid is mainly used to produce an array of other chemicals that have one surprising thing in common - they are exceptionally un-reactive.
"The result of this extreme reactivity of the element fluorine itself means that its compounds are staggeringly stable," explains Sella. "Molecules surrounded by fluorine are like a tortoise surrounded by a carapace that you cannot break through."
Consider Teflon, which comprises long chains of carbon atoms surrounded by fluorine. The carbon-fluorine bond is particularly strong and chemically impenetrable, making this plastic the perfect inert substance for non-stick pans.
Then there's toothpaste. It contains tiny amounts of those aggressive fluoride ions. But once in your mouth, the ions combine with calcium in your teeth to provide a protective coating of chemically resilient calcium fluoride.
Fluorine is an evil gas. And it is also used to manufacture a string of other artificial gases, some of which nearly left mankind exposed to burning ultraviolet light - and are even now warming the planet."Fluorine is the tyrannosaurus rex of the periodic table," says chemistry professor Andrea Sella. "It will react spontaneously with every other element except for helium, neon and argon."
If you ever happen to lay eyes on pure, elemental fluorine, it looks fairly innocuous - a pale yellow gas - but in truth it is so dangerous that Sella's department at University College London does not even keep it in stock.
It produces a smell similar to chlorine, he says, "but generally, if you smell fluorine what you do is run away as fast as you can".
Sella does have a jar of another frightening material - hydrofluoric acid or HF. Its acidity - that is, the reactiveness of the hydrogen ions it contains - is not actually quite as strong as that of the better known hydrochloric or sulphuric acids.
But it is nonetheless an exceptionally vicious chemical, because the ferocious fluorine ions can penetrate deep into your body. "It's an unbelievably painful burn, and one that you cannot really treat, because it's gone inside," says Sella.
Once inside, the fluoride gobbles up the body's calcium, which can lead to heart failure in extreme cases.
HF's corrosiveness does have its uses, such as etching glass or microchip circuitry. Yet this noxious acid is mainly used to produce an array of other chemicals that have one surprising thing in common - they are exceptionally un-reactive.
"The result of this extreme reactivity of the element fluorine itself means that its compounds are staggeringly stable," explains Sella. "Molecules surrounded by fluorine are like a tortoise surrounded by a carapace that you cannot break through."
Consider Teflon, which comprises long chains of carbon atoms surrounded by fluorine. The carbon-fluorine bond is particularly strong and chemically impenetrable, making this plastic the perfect inert substance for non-stick pans.Then there's toothpaste. It contains tiny amounts of those aggressive fluoride ions. But once in your mouth, the ions combine with calcium in your teeth to provide a protective coating of chemically resilient calcium fluoride.
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10:02 AM
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