Fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...

(₉F) has 18 known

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) ...

s ranging from to (with the exception of ) and two

isomers In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Iso ...

( and ). Only fluorine-19 is stable and naturally occurring in more than trace quantities; therefore, fluorine is a monoisotopic and mononuclidic element. The longest-lived radioisotope is ; it has a half-life of . All other fluorine isotopes have half-lives of less than a minute, and most of those less than a second. The least stable known isotope is , whose half-life is , corresponding to a

resonance width In physics and engineering, the quality factor or ''Q'' factor is a dimensionless parameter that describes how underdamped an oscillator or resonator is. It is defined as the ratio of the initial energy stored in the resonator to the energy los ...

of .

List of isotopes

, - , , style="text-align:right" , 9 , style="text-align:right" , 4 , # , , p ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , 1/2+# , , , - , , style="text-align:right" , 9 , style="text-align:right" , 5 , ,
[] , p ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , 2− , , , - , , style="text-align:right" , 9 , style="text-align:right" , 6 , ,
[] , p , , 1/2+ , , , - , , style="text-align:right" , 9 , style="text-align:right" , 7 , ,
[] , p , , 0− , , , - , , style="text-align:right" , 9 , style="text-align:right" , 8 , , , Beta decay, β⁺ , , 5/2+ , , , - , Fluorine-18, Has medicinal uses , style="text-align:right" , 9 , style="text-align:right" , 9 , , , β⁺ , , 1+ , Trace , , - , style="text-indent:1em" , , colspan="3" style="text-indent:2em" , , , IT , , 5+ , , , - , , style="text-align:right" , 9 , style="text-align:right" , 10 , , colspan=3 align=center, Stable , 1/2+ , colspan=2 style="text-align:center", 1 , - , , style="text-align:right" , 9 , style="text-align:right" , 11 , , , β⁻ , , 2+ , , , - , , style="text-align:right" , 9 , style="text-align:right" , 12 , , , β⁻ , , 5/2+ , , , - , rowspan=2, , rowspan=2 style="text-align:right" , 9 , rowspan=2 style="text-align:right" , 13 , rowspan=2, , rowspan=2, , β⁻ (> ) , , rowspan=2, (4+) , rowspan=2, , rowspan=2, , - , β⁻n (< ) , , - , rowspan=2, , rowspan=2 style="text-align:right" , 9 , rowspan=2 style="text-align:right" , 14 , rowspan=2, , rowspan=2, , β⁻ (> ) , , rowspan=2, 5/2+ , rowspan=2, , rowspan=2, , - , β⁻n (< ) , , - , rowspan=2, , rowspan=2 style="text-align:right" , 9 , rowspan=2 style="text-align:right" , 15 , rowspan=2, , rowspan=2, , β⁻ (> ) , , rowspan=2, 3+ , rowspan=2, , rowspan=2, , - , β⁻n (< ) , , - , rowspan=3, , rowspan=3 style="text-align:right" , 9 , rowspan=3 style="text-align:right" , 16 , rowspan=3, , rowspan=3, , β⁻ () , , rowspan=3, (5/2+) , rowspan=3, , rowspan=3, , - , β⁻n () , , - , β⁻2n ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , - , rowspan=3, , rowspan=3 style="text-align:right" , 9 , rowspan=3 style="text-align:right" , 17 , rowspan=3, , rowspan=3, , β⁻ () , , rowspan=3, 1+ , rowspan=3, , rowspan=3, , - , β⁻n () , , - , β⁻2n ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , - , rowspan=3 style="text-indent:1em" , , rowspan=3 colspan="3" style="text-indent:2em" , , rowspan=3 , , IT () , , rowspan=3, (4+) , rowspan=3, , rowspan=3, , - , β⁻n () , , - , β⁻ ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , - , rowspan=3, , rowspan=3 style="text-align:right" , 9 , rowspan=3 style="text-align:right" , 18 , rowspan=3, , rowspan=3, , β⁻n () , , rowspan=3, 5/2+# , rowspan=3, , rowspan=3, , - , β⁻ () , , - , β⁻2n ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , - , , style="text-align:right" , 9 , style="text-align:right" , 19 , , , n , , (4−) , , , - , rowspan=3, , rowspan=3 style="text-align:right" , 9 , rowspan=3 style="text-align:right" , 20 , rowspan=3, , rowspan=3, , β⁻n () , , rowspan=3, (5/2+) , rowspan=3, , rowspan=3, , - , β⁻ () , , - , β⁻2n ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , - , rowspan=3, , rowspan=3 style="text-align:right" , 9 , rowspan=3 style="text-align:right" , 22 , rowspan=3, # , rowspan=3, # , β⁻ ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , rowspan=3, 5/2+# , rowspan=3, , rowspan=3, , - , β⁻n ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , - , β⁻2n ?Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide. , ? , -

Fluorine-18

Of the unstable nuclides of fluorine, has the longest half-life, . It decays to via β⁺ decay. For this reason is a commercially important source of

positrons The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. It has an electric charge of +1 '' e'', a spin of 1/2 (the same as the electron), and the same mass as an electron. When a positron collides w ...

. Its major value is in the production of the radiopharmaceutical fludeoxyglucose, used in

positron emission tomography Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in Metabolism, metabolic processes, and in other physiological activities including bl ...

in medicine. Fluorine-18 is the lightest unstable nuclide with equal odd numbers of protons and neutrons, having 9 of each. (See also the "magic numbers" discussion of nuclide stability.)

Fluorine-19

Fluorine-19 is the only stable

fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...

. Its abundance is ; no other isotopes of fluorine exist in significant quantities. Its binding energy is . Fluorine-19 is NMR-active with a spin of 1/2+, so it is used in fluorine-19 NMR spectroscopy.

Fluorine-20

Fluorine-20 is an unstable

. It has a half-life of and decays via beta decay to the stable nuclide . Its

specific radioactivity Specific activity is the activity per unit mass of a radionuclide and is a physical property of that radionuclide. Activity is a quantity (for which the SI unit is the becquerel) related to radioactivity, and is defined as the number of rad ...

is and has a

mean lifetime A quantity is subject to exponential decay if it decreases at a rate Proportionality (mathematics), proportional to its current value. Symbolically, this process can be expressed by the following differential equation, where is the quantity and ...

of .

Fluorine-21

Fluorine-21, as with fluorine-20, is also an unstable

of fluorine. It has a half-life of . It undergoes beta decay as well, decaying to , which is a stable nuclide. Its specific activity is .

Isomers

Only two

nuclear isomers A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy higher energy levels than in the ground state of the same nucleus. "Metastable" describes nuclei whose excited states have ha ...

(long-lived excited nuclear states), fluorine-18m and fluorine-26m, have been characterized. The half-life of before it undergoes

isomeric transition A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy higher energy levels than in the ground state of the same nucleus. "Metastable" describes nuclei whose excited states have ha ...

is . This is less than the decay half-life of any of the fluorine radioisotope nuclear ground states except for mass numbers 14–16, 28, and 31. The half-life of is ; it decays mainly to its ground state of or (rarely, via beta-minus decay) to one of high excited states of with delayed neutron emission.

External links

Information on Fluorine-21 from ''Wolframalpha.com''Information on Fluorine-20 from ''Wolframalpha.com''

References

{{Navbox element isotopes Fluorine