Isotopes of fluorine

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Isotopes of fluorine  (9F)
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
18F trace 109.734 min β+ 18O
19F100% stable
[1]
Standard atomic weight Ar°(F)

Fluorine (9F) has 19 known isotopes ranging from 13
F
 to 31
F
 and two isomers (18m
F
 and 26m
F
). Only fluorine-19 is stable and naturally occurring in more than trace quantities; therefore, fluorine is a monoisotopic and mononuclidic element.

Contents

The longest-lived radioisotope is 18
F
; 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 14
F
, whose half-life is 500(60) yoctoseconds, [4] corresponding to a resonance width of 910(100) keV.

List of isotopes

Nuclide
[n 1] 		Z N Isotopic mass (Da) [5]
[n 2] [n 3] 		Half-life [4]
[n 4] 		Decay
mode [4]
[n 5] 		Daughter
isotope
[n 6] 		Spin and
parity [4]
[n 7] [n 4] 		Isotopic
abundance
Excitation energy
13
F
 [6] 		9413.045120(540)# p  ? [n 8] 12
O
 ?		1/2+#
14
F
9514.034320(40)500(60) ys
[910(100) keV]		 p  ? [n 8] 13
O
 ?		2−
15
F
9615.017785(15)1.1(3) zs
[376 keV]		p14
O
1/2+
16
F
9716.011460(6)21(5) zs
[21.3(5.1) keV]		p15
O
0−
17
F
 [n 9] 		9817.00209524(27)64.370(27) s β+ 17
O
5/2+
18
F
 [n 10] 		9918.0009373(5)109.734(8) minβ+18
O
1+Trace
18m
F
1121.36(15) keV162(7) ns IT 18
F
5+
19
F
91018.998403162067(883)Stable1/2+1
20
F
91119.99998125(3)11.0062(80) sβ−20
Ne
2+
21
F
91220.9999489(19)4.158(20) sβ−21
Ne
5/2+
22
F
91322.002999(13)4.23(4) sβ− (> 89%)22
Ne
(4+)
β−n (< 11%)21
Ne
23
F
91423.003530(40)2.23(14) sβ− (> 86%)23
Ne
5/2+
β−n (< 14%)22
Ne
24
F
91524.008100(100)384(16) msβ− (> 94.1%)24
Ne
3+
β−n (< 5.9%)23
Ne
25
F
91625.012170(100)80(9) msβ− (76.9(4.5)%)25
Ne
(5/2+)
β−n (23.1(4.5)%)24
Ne
β−2n ? [n 8] 23
Ne
 ?
26
F
91726.020050(110)8.2(9) msβ− (86.5(4.0)%)26
Ne
1+
β−n (13.5(4.0)%)25
Ne
β−2n ? [n 8] 24
Ne
 ?
26m
F
643.4(1) keV2.2(1) msIT (82(11)%)26
F
(4+)
β−n (12(8)%)25
Ne
β− ? [n 8] 26
Ne
 ?
27
F
91827.026980(130)5.0(2) msβ−n (77(21)%)26
Ne
5/2+#
β− (23(21)%)27
Ne
β−2n ? [n 8] 25
Ne
 ?
28
F
91928.035860(130)46 zsn27
F
(4−)
29
F
92029.043100(560)2.5(3) msβ−n (60(40)%)28
Ne
(5/2+)
β− (40(40)%)29
Ne
β−2n ? [n 8] 27
Ne
 ?
30
F
 [7] 		92130.05256(54)#0.96+0.56
−0.41 zs		n29
F
31
F
92231.06020(570)#2 ms# [> 260 ns]β− ? [n 8] 31
Ne
 ?		5/2+#
β−n ? [n 8] 30
Ne
 ?
β−2n ? [n 8] 29
Ne
 ?
This table header & footer:
  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. 1 2 # – 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. 1 2 3 4 5 6 7 8 9 10 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

Of the unstable nuclides of fluorine, 18
F
 has the longest half-life, 109.734(8) min. It decays to 18
O
 via β+ decay. For this reason 18
F
 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.) [8]

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 20
Ne
. 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 21
Ne
, 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. [4] The half-life of 18m
F
 before it undergoes isomeric transition is 162(7)  nanoseconds . [4] 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. [9] The half-life of 26m
F
 is 2.2(1) milliseconds; it decays mainly to its ground state of 26
F
 or (rarely, via beta-minus decay) to one of high excited states of 26
Ne
 with delayed neutron emission. [4]

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References

  1. ↑ Chisté & Bé 2011.
  2. ↑ "Standard Atomic Weights: Fluorine". CIAAW. 2021.
  3. ↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN   1365-3075.
  4. 1 2 3 4 5 6 7 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  5. ↑ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  6. ↑ 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. Bibcode:2021PhRvL.126m2501C. doi:10.1103/PhysRevLett.126.132501. OSTI   1773500. PMID   33861136. S2CID   233259561 . Retrieved 5 April 2021.
  7. ↑ Kahlbow, J.; et al. (SAMURAI21-NeuLAND Collaboration) (2024-08-23). "Magicity versus Superfluidity around 28O viewed from the Study of 30F". Physical Review Letters. 133 (8). doi: 10.1103/PhysRevLett.133.082501 . ISSN   0031-9007.
  8. ↑ National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
  9. ↑ Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.

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