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Fluorine can be removed from the ocean by deposition of terrigenous or authigenic sediments, or subduction of the oceanic lithosphere. The fluorine cycle is the series of biogeochemical processes through which fluorine moves through the lithosphere, hydrosphere, atmosphere, and biosphere. Fluorine originates from the Earth’s crust, and its ...
Perfluoroalkanes are very stable because of the strength of the carbon–fluorine bond, one of the strongest in organic chemistry. [4] Its strength is a result of the electronegativity of fluorine imparting partial ionic character through partial charges on the carbon and fluorine atoms, which shorten and strengthen the bond (compared to carbon-hydrogen bonds) through favorable covalent ...
A special numbering system is to be used for fluorinated alkanes, prefixed with Freon-, R-, CFC- and HCFC-, where the rightmost value indicates the number of fluorine atoms, the next value to the left is the number of hydrogen atoms plus 1, and the next value to the left is the number of carbon atoms less one (zeroes are not stated), and the ...
Broadly speaking, all PFAS have a chain of carbon atoms bonded to fluorine atoms. Some substances have every carbon-hydrogen bond replaced by a fluorine atom (per-fluorinated) others have only ...
Ozone is a highly reactive molecule that easily reduces to the more stable oxygen form with the assistance of a catalyst. Cl and Br atoms destroy ozone molecules through a variety of catalytic cycles. In the simplest example of such a cycle, [18] a chlorine atom reacts with an ozone molecule (O
Fluorine has the lowest polarizability of all atoms: 0.56 10 −24 cm 3. [1] This causes very weak dispersion forces between polyfluorinated molecules and is the reason for the often-observed boiling point reduction on fluorination as well as for the simultaneous hydrophobicity and lipophobicity of polyfluorinated compounds whereas other ...
They are frequently used in air conditioning and as refrigerants; R-134a (1,1,1,2-tetrafluoroethane) is one of the most commonly used HFC refrigerants. In order to aid the recovery of the stratospheric ozone layer, HFCs were adopted to replace the more potent chlorofluorocarbons (CFCs), which were phased out from use by the Montreal Protocol ...
Isotopes are atoms of the same element that have a different number of neutrons in their nuclei. Air , freshwater and seawater contain mostly oxygen-16 ( 16 O). Oxygen-18 ( 18 O) occurs in approximately one oxygen atom in every five hundred and has a slightly higher mass than oxygen-16, as it has two extra neutrons.