Isotopes of fluorine

Short description: Nuclides with atomic number of 9 but with different mass numbers

Fluorine (9F) has 18 known isotopes ranging from 13F to 31F (with the exception of 30F) and two isomers (18mF and 26mF). 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 18F; it has a half-life of 109.734(8) min. 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 14F, whose half-life is 500(60) yoctoseconds,[1] corresponding to a resonance width of 910(100) keV.

## Contents

* 1 List of isotopes
* 2 Fluorine-18
* 3 Fluorine-19
* 4 Fluorine-20
* 5 Fluorine-21
* 6 Isomers
* 7 External links
* 8 References
* 9 Sources

## List of isotopes

Nuclide
[n 1] | Z | N | Isotopic mass (u)
[n 2][n 3] | Half-life
[n 4] | Decay
mode
[n 5] | Daughter
isotope
[n 6] | Spin and
parity
[n 7][n 4] | Physics:Natural abundance (mole fraction)

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Excitation energy  | Normal proportion  | Range of variation
13F[2] | 9  | 4  | 13.045120(540)#  |  | p ?[n 8] | 12O ?  | 1/2+#  |  |
14F | 9  | 5  | 14.034320(40) | 500(60) ys
[910(100) keV]  | p ?[n 8] | 13O ?  | 2−  |  |
15F | 9  | 6  | 15.017785(15) | 1.1(3) zs
[376 keV]  | p  | 14O | 1/2+  |  |
16F | 9  | 7  | 16.011460(6) | 21(5) zs
[21.3(5.1) keV]  | p  | 15O | 0−  |  |
17F[n 9] | 9  | 8  | 17.00209524(27) | 64.370(27) s | β+ | 17O | 5/2+  |  |
18F[n 10] | 9  | 9  | 18.0009373(5) | 109.734(8) min | β+ | 18O | 1+  | Trace  |
18mF | 1121.36(15) keV | 162(7) ns | IT  | 18F | 5+  |  |
19F | 9  | 10  | 18.998403162067(883) | Stable | 1/2+  | 1
20F | 9  | 11  | 19.99998125(3) | 11.0062(80) s | β− | 20Ne | 2+  |  |
21F | 9  | 12  | 20.9999489(19) | 4.158(20) s | β− | 21Ne | 5/2+  |  |
22F | 9  | 13  | 22.002999(13) | 4.23(4) s | β− (> 89%)  | 22Ne | (4+)  |  |
β−n (< 11%)  | 21Ne
23F | 9  | 14  | 23.003530(40) | 2.23(14) s | β− (> 86%)  | 23Ne | 5/2+  |  |
β−n (< 14%)  | 22Ne
24F | 9  | 15  | 24.008100(100) | 384(16) ms | β− (> 94.1%)  | 24Ne | 3+  |  |
β−n (< 5.9%)  | 23Ne
25F | 9  | 16  | 25.012170(100) | 80(9) ms | β− (76.9(4.5)%)  | 25Ne | (5/2+)  |  |
β−n (23.1(4.5)%)  | 24Ne
β−2n ?[n 8] | 23Ne ?
26F | 9  | 17  | 26.020050(110) | 8.2(9) ms | β− (86.5(4.0)%)  | 26Ne | 1+  |  |
β−n (13.5(4.0)%)  | 25Ne
β−2n ?[n 8] | 24Ne ?
26mF | 643.4(1) keV | 2.2(1) ms | IT (82(11)%)  | 26F | (4+)  |  |
β−n (12(8)%)  | 25Ne
β− ?[n 8] | 26Ne ?
27F | 9  | 18  | 27.026980(130) | 5.0(2) ms | β−n (77(21)%)  | 26Ne | 5/2+#  |  |
β− (23(21)%)  | 27Ne
β−2n ?[n 8] | 25Ne ?
28F | 9  | 19  | 28.035860(130) | 46 zs | n  | 27F | (4−)  |  |
29F | 9  | 20  | 29.043100(560) | 2.5(3) ms | β−n (60(40)%)  | 28Ne | (5/2+)  |  |
β− (40(40)%)  | 29Ne
β−2n ?[n 8] | 27Ne ?
31F | 9  | 22  | 31.06020(570)#  | 2 ms# [> 260 ns]  | β− ?[n 8] | 31Ne ?  | 5/2+#  |  |
β−n ?[n 8] | 30Ne ?
β−2n ?[n 8] | 29Ne ?

1. ↑ mF - Excited nuclear isomer.
2. ↑ ( ) - Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. ↑ # - Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. ↑ 4.0 4.1 # - Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. ↑ Modes of decay:  EC: | Electron capture

|

IT: | Isomeric transition
n: | Neutron emission
p: | Proton emission
6. ↑ Bold symbol as daughter - Daughter product is stable.
7. ↑ ( ) spin value - Indicates spin with weak assignment arguments.
8. ↑ 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.
9. ↑ Intermediate product of various CNO cycles in stellar nucleosynthesis as part of the process producing helium from hydrogen
10. ↑ Has medicinal uses

## Fluorine-18

Main article: Physics:Fluorine-18

Of the unstable nuclides of fluorine, 18F has the longest half-life, 109.734(8) min. It decays to 18O via β+ decay. For this reason 18F is a commercially important source of positrons. Its major value is in the production of the radiopharmaceutical fludeoxyglucose, used in positron emission tomography 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.)[3]

## Fluorine-19

Fluorine-19 is the only stable isotope of fluorine. Its abundance is 100%; no other isotopes of fluorine exist in significant quantities. Its binding energy is 147801.3648(38) keV. 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 isotope of fluorine. It has a half-life of 11.0062(80) s and decays via beta decay to the stable nuclide 20Ne. Its specific radioactivity is 1.8693(14)×10+21 Bq/g and has a mean lifetime of 15.879(12) s.

## Fluorine-21

Fluorine-21, as with fluorine-20, is also an unstable isotope of fluorine. It has a half-life of 4.158(20) s. It undergoes beta decay as well, decaying to 21Ne, which is a stable nuclide. Its specific activity is 4.781(23)×10+21 Bq/g.

## Isomers

Only two nuclear isomers (long-lived excited nuclear states), fluorine-18m and fluorine-26m, have been characterized.[1] The half-life of 18mF before it undergoes isomeric transition is 162(7) nanoseconds.[1] 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. [4] The half-life of 26mF is 2.2(1) milliseconds; it decays mainly to its ground state of 26F or (rarely, via beta-minus decay) to one of high excited states of 26Ne with delayed neutron emission.[1]

## External links

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

## References

1. ↑ 1.0 1.1 1.2 1.3 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties". Chinese Physics C 45 (3). doi:10.1088/1674-1137/abddae. https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf.
2. ↑ Charity, R. J. (2 April 2021). "Observation of the Exotic Isotope 13 F Located Four Neutrons beyond the Proton Drip Line". Physical Review Letters 126 (13): 2501. doi:10.1103/PhysRevLett.126.132501. PMID 33861136. Bibcode: 2021PhRvL.126m2501C. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.132501. Retrieved 5 April 2021.
3. ↑ National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/.
4. ↑ Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties". Chinese Physics C 41 (3): 030001. doi:10.1088/1674-1137/41/3/030001. Bibcode: 2017ChPhC..41c0001A. https://www-nds.iaea.org/amdc/ame2016/NUBASE2016.pdf.

## Sources

* Chisté, V.; Bé, M. M. (2011). Bé, M. M.. ed. ﻿Table de radionucléides﻿ (Report). CEA (Commissariat à l'énergie atomique et aux énergies alternatives), LIST, LNE-LNHB (Laboratoire National Henri Becquerel/Commissariat à l'Energie Atomique).

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