25 January: Fluoride Day

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.