Page 36 - Curriculum Visions Dynamic Book

Fluorine
Fluorine, the 13th most abundant element, gets its name from the Latin fluo, meaning to flow. This is because, until recent times, fluorine compounds were used as a flux, a material that helps molten metal flow.
Compounds containing fluorine are found in all living things, from plant tissues to animal bones and blood. They are also widely found in water and in rocks. Fluorspar, often called Blue John, is the most common compound of fluorine and contains beautiful crystals (page 8).
Fluorine is a tiny atom and the most reactive of all the elements in the universe, which is why it never occurs
in nature on its own. It can only be separated from compounds using large amounts of electrical energy.
The fluorine thus produced is a pale yellow gas, highly poisonous and so corrosive that it is extremely difficult to store. Usually a vessel containing fluorine has to be coated inside with a plastic itself made with fluorine.
Compounds of fluorine are called fluorides. Most fluorides do not dissolve in water or oil and they do not catch fire. Uranium hexafluoride was used in making the first atomic bomb.
Tetrafluoroethene
Tetrafluoroethene is a material containing fluorine that has proved very popular. It is a polymer made from an extract of crude oil (ethene) and fluorine.
Polytetrafluoroethene is a soft white plastic (polymer) that virtually
nothing sticks to. It is nonreactive with most chemicals (that is, it resists corrosion), heat resistant, and a very good electrical insulator. It is the nonstick surface used on many household cooking utensils and cookware.
Fluorine Carbon
 The monomer tetrafluoroethene that is polymerised to make polytetrafluoroethene, known as Teflon.
Because of all these useful properties, tetrafluoroethene is used worldwide for tubes, gaskets and seals that must not deteriorate. It is also used for making bearings and as a coating on saw blades.
This material is one of the main sources of demand for fluorine.
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