Fluoride Day:
Fluoride is basically a type of ion of the element fluorine.
1.
The element's name comes from the fact that it was used to lower
the melting points for metal ores (first documented by Georgius Agricola in
1529), making them easier to work with. Hence the Latin verb fluo meaning
"flow" became associated with it. It was Sir Humphrey Davy who first
proposed the name.
2.
Andreas Sigismund Marggraf described another early use in 1764. He
heated fluorite with sulphuric acid. The resulting solution corroded its glass
container, so hydrofluoric acid became an agent used for glass etching.
3.
Fluorine is highly reactive and forms bonds easily with other
elements. It wasn't until 1810 that scientists began to suspect that fluorine
was an element. It took until 1886 before anyone managed to prove it. Fluorine
proved difficult and dangerous to isolate from its compounds and several
scientists died in the attempt. They became known as "fluorine
martyrs".
4.
In 1886, French chemist Henri Moissan managed to isolate elemental
fluorine using low-temperature electrolysis. He won the 1906 Nobel Prize in
Chemistry for this, for, as the citation read, "the great services
rendered by him in his investigation and isolation of the element fluorine ...
The whole world has admired the great experimental skill with which you have
studied that savage beast among the elements".
5.
Fluorine's symbol is F and its atomic number is 9. Its melting
point is 53.48 K (−219.67 °C, −363.41 °F) and its boiling point is 85.03 K
(−188.11 °C, −306.60 °F).
6.
It's the 24th most common element in the universe and the 13th
most common on Earth.
7.
In normal conditions, it is a pale Yellow gas with a pungent
odour. In liquid form it is bright yellow.
8.
Fluorine has no known metabolic role in mammals. Some plants make
organofluorine poisons to deter herbivores. That said, studies in the 20th
century found that it did have the effect of reducing tooth decay in areas
where it was naturally present in drinking Water, so since the 1940s 6% of the
world's population have small amounts of fluorine added to their drinking
water.
9.
At least 17,000 metric tons of fluorine are produced each year.
Industrial production of the stuff dates back to World War II when the
Manhattan Project used huge quantities for uranium enrichment. Meanwhile, Germany used high-temperature electrolysis to make incendiary chlorine
trifluoride.
10.
Today it is used to make fluorosurfactants which are small
flourine compounds which repel water and can be added to fabric as
waterproofing. It's also used in about 20% of modern drugs, because the bond
between fluorine and the active ingredients is slow to break down, so it
lengthens dosage periods.