Search results
Results From The WOW.Com Content Network
Fluorine is a chemical element; it has symbol F and atomic number 9. It is the lightest halogen [note 1] and exists at standard conditions as pale yellow diatomic gas. Fluorine is extremely reactive as it reacts with all other elements except for the light inert gases. It is highly toxic.
PET scan using fluorine-18. Fluorine may interact with biological systems in the form of fluorine-containing compounds. Though elemental fluorine (F 2) is very rare in everyday life, fluorine-containing compounds such as fluorite occur naturally as minerals. Naturally occurring organofluorine compounds are extremely rare. Man-made fluoride ...
And any created fluorine within stars is rapidly eliminated through strong nuclear fusion reactions—either with hydrogen to form oxygen and helium, or with helium to make neon and hydrogen. [ 2 ] [ 3 ] The presence of fluorine at all—outside of temporary existence in stars—is somewhat of a mystery because of the need to escape these ...
fluorine: 9: 3a: Affects bone density in humans; creates fluoroapatite, which makes tooth enamel hard and relatively impervious to chemical action, compared to bone. [11] Improves growth in rats; has pharmacologic effects – helps to treat other deficiencies, e.g. of iron. Absence of fluorine has no clear adverse consequences in animals. [21]
Moissan's fluorine cell, from his 1887 publication. Fluorine is a relatively new element in human applications. In ancient times, only minor uses of fluorine-containing minerals existed. The industrial use of fluorite, fluorine's source mineral, was first described by early scientist Georgius Agricola in the 16th century, in the context of ...
Fluorine is an important element for biological systems. From a mammalian health perspective, it is notable as a component of fluorapatite , a key mineral in the teeth of humans that have been exposed to fluorine, as well as shark and fish teeth. [ 4 ]
The fluorine–fluorine bond of the difluorine molecule is relatively weak when compared to the bonds of heavier dihalogen molecules. The bond energy is significantly weaker than those of Cl 2 or Br 2 molecules and similar to the easily cleaved oxygen–oxygen bonds of peroxides or nitrogen–nitrogen bonds of hydrazines. [8]
The World Health Organization, looking at global public health, identifies fluoride as one of a few chemicals for which the contribution from drinking-water to overall intake is an important factor in preventing disease. This is because there is clear evidence that optimal concentrations of fluoride provide protection against cavities, both in ...