Fluorine is an extremely reactive chemical element with atomic number 9. At standard conditions, pure fluorine is a toxic pale yellow diatomic gas. Fluorite, the element's primary mineral source, was first described in 1529, and fluorine was proposed as an element in 1810. As the lightest halogen and most electronegative reactive element, it is difficult to separate from its compounds, and several early experimenters died or were injured in the attempt. French chemist Henri Moissan finally succeeded in 1886 using low-temperature electrolysis, a process still used today. Global fluorochemical sales amount to more than US$15 billion a year, including in toothpaste and water fluoridation, refrigerants, Teflon for electrical insulation and cookware, pharmaceuticals, aluminium refining and steelmaking. Fluorocarbon gases are generally greenhouse gases. Fluorine has no known metabolic role in mammals, but a few plants and sea sponges synthesize poisonous fluorocarbons to deter predators.

Read more: https://en.wikipedia.org/wiki/Fluorine

_______________________________ Today's selected anniversaries:

1536:

King Henry VIII of England suffered a serious accident while jousting, receiving injuries which may have caused his later obesity and erratic personality. https://en.wikipedia.org/wiki/Henry_VIII

1848:

James W. Marshall discovered gold at Sutter's Mill in Coloma, California, leading to the California gold rush. https://en.wikipedia.org/wiki/California_gold_rush

1972:

Japanese soldier Shoichi Yokoi was found in the jungles of Guam, where he had been hiding since the end of World War II. https://en.wikipedia.org/wiki/Shoichi_Yokoi

1977:

During the Spanish transition to democracy, neo-fascists attacked an office in Madrid, killing five people and injuring four others. https://en.wikipedia.org/wiki/1977_Atocha_massacre

_____________________________ Wiktionary's word of the day:

rhombicosidodecahedron: (geometry) An Archimedean solid with 62 regular faces (20 triangles, 30 squares, and 12 pentagons), 60 vertices and 120 edges. https://en.wiktionary.org/wiki/rhombicosidodecahedron

___________________________ Wikiquote quote of the day:

If you don’t want to be replaced by a machine, don’t try to act like one!   --Arno Allan Penzias https://en.wikiquote.org/wiki/Arno_Allan_Penzias