| Group | 17 | Melting point | -219.67 oC, -363.406 oF, 53.48 K |
| Period | 2 | Boiling point | -188.11 oC, -306.598 oF, 85.04 K |
| Block | p | Density (kg m-3) | 1140 (73 K) |
| Atomic number | 9 | Relative atomic mass | 18.998 |
| State at room temperature | Gas | Key isotopes | 19F |
| Electron configuration | [He] 2s22p5 | CAS number | 7782-41-4 |
| ChemSpider ID | 4514530 | ChemSpider is a free chemical structure database | |
Image explanation
Image reflects the highly reactive nature of the element.
Appearance
Fluorine salts, known as fluorides, were used for centuries in welding metals and for frosting glass before the element itself was isolated. Fluorine gas is the most reactive of all the elements and quickly attacks all metals - steel wool bursts into flames when exposed to it ! Fluorine is used to make uranium hexafluoride, needed by the nuclear power industry, and sulfur hexafluoride insulating gas for high-power electricity transformers, and to treat Polythene to make it impermeable to solvents. Fluoride is an essential ion for animals, strengthening teeth and bones. It is added to drinking water in some areas and to toothpaste. The average human body contains about 3 milligrammes; too much fluoride is toxic.
Uses
There was no commercial production of fluorine until World War II, when the production of the atom bomb and other nuclear energy projects made it necessary to produce large quantities. Fluorine is used to make uranium hexafluoride, needed by the nuclear power industry, and sulfur hexafluoride insulating gas for high-power electricity transformers, and to treat Polythene to make it impermeable to solvents. The element and its compounds are used in producing uranium and many fluorochemicals, including high-temperature plastics, and especially Teflon. Hydrofluoric acid is used for etching the glass of light bulbs and in similar applications, and fluorochloro-hydrocarbons are used in air conditioning and refrigeration.
Biological role
Fluoride is an essential ion for animals, strengthening teeth and bones. The presence of fluorides below 2ppm in drinking water is believed to prevent dental cavities, but above this concentration may cause mottled enamel in children while they are acquiring permanent teeth. The average human body contains about 3 milligrammes; too much fluoride is toxic. The element fluorine in its purest form is highly toxic.
Natural abundance
Fluorine occurs chiefly in the minerals fluorspar and cryolite, but is rather widely distributed in other minerals. It can be obtained by electrolysing a solution of potassium hydrogen fluoride in anhydrous hydrogen fluoride in a vessel of metal or transparent fluorspar. Fluorine salts, known as fluorides, were used for centuries in welding metals and for frosting glass before the element itself was isolated. Fluorine gas is the most reactive of all the elements and quickly attacks all metals for example steel wool bursts into flames when exposed to it.
| Atomic radius, non-bonded (Å) | 1.470 | Covalent radius (Å) | 0.6 |
| Electron affinity (kJ mol-1) | 328.147 |
Electronegativity (Pauling scale) |
3.980 |
|
Ionisation energies (kJ mol-1) |
1st
1681.045
2nd
3374.167
3rd
6050.436
4th
8407.706
5th
11022.746
6th
15164.115
7th
17867.719
8th
92038.367
|
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| Covalent bonds |
|
|
|
| Common oxidation states | -1 | ||||
| Isotopes | Isotope | Atomic mass | Natural abundance (%) | Half life | Mode of decay |
| 19F | 18.998 | 100 | - | - | |
|
Molar heat capacity (J mol-1 K-1) |
31.304 | Young's modulus (GPa) | Unknown | |||||||||||
| Shear modulus (GPa) | Unknown | Bulk modulus (GPa) | Unknown | |||||||||||
| Vapour pressure | ||||||||||||||
| Temperature (K) |
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| Pressure (Pa) |
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Images: Visual Elements © Murray Robertson 2011
Mining and Sourcing data: British Geological Survey – natural environment research council.
Text: John Emsley Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, 2nd Edition, 2011.
Data: CRC Handbook of Chemistry and Physics, CRC Press, 92nd Edition, 2011.
G. W. C. Kaye and T. H. Laby Tables of Physical and Chemical Constants, Longman, 16th Edition, 1995.
Members of the RSC can access these books through our library.
Mining and Sourcing data: British Geological Survey – natural environment research council.
Text: John Emsley Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, 2nd Edition, 2011.
Data: CRC Handbook of Chemistry and Physics, CRC Press, 92nd Edition, 2011.
G. W. C. Kaye and T. H. Laby Tables of Physical and Chemical Constants, Longman, 16th Edition, 1995.
Members of the RSC can access these books through our library.
