Isotopes of fluorine

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Isotopes of fluorine  (9F)
Main isotopes [1] Decay
Isotope abun­dance half-life (t1/2) mode pro­duct
17F synth 64.37 s β+ 17O
18F trace 109.734 minβ+18O
19F100% stable
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 a mononuclidic element.

Contents

The longest-lived radioisotope is 18
F
with a half-life of 109.734 minutes, followed by 17
F
with 64.37 seconds. These unstable isotopes participate in the CNO cycle within stars. All other fluorine isotopes have half-lives of less than 12 seconds, and most of those less than 1/2 second.

List of isotopes

Nuclide
[n 1]
Z N Isotopic mass (Da) [4]
[n 2] [n 3]
Half-life [1]
[n 4]
Decay
mode
[1]
[n 5]
Daughter
isotope

[n 6]
Spin and
parity [1]
[n 7] [n 4]
Isotopic
abundance
Excitation energy
13
F
[5]
9413.045120(540)# p  ?12
O
1/2+#
14
F
9514.034320(40)500(60) ys
[910(100) keV]
p  ?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 8]
9817.00209524(27)64.370(27) s β+ 17
O
5/2+
18
F
[n 9]
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) sβ20
Ne
2+
21
F
91220.9999489(19)4.158(20) sβ21
Ne
5/2+
22
F
91322.002999(13)4.23(4) sβ (> 89%)22
Ne
(4+)
βn (< 11%)21
Ne
23
F
91423.003530(40)2.23(14) sβ (> 86%)23
Ne
5/2+
βn (< 14%)22
Ne
24
F
91524.008100(100)384(16) msβ (> 94.1%)24
Ne
3+
βn (< 5.9%)23
Ne
25
F
91625.012170(100)80(9) msβ (76.9(4.5)%)25
Ne
(5/2+)
βn (23.1(4.5)%)24
Ne
β2n ?23
Ne
 ?
26
F
91726.020050(110)8.2(9) msβ (86.5(4.0)%)26
Ne
1+
βn (13.5(4.0)%)25
Ne
β2n ?24
Ne
 ?
26m
F
643.4(1) keV2.2(1) msIT (82(11)%)26
F
(4+)
βn (12(8)%)25
Ne
β ?26
Ne
 ?
27
F
91827.026980(130)5.0(2) msβn (77(21)%)26
Ne
5/2+#
β (23(21)%)27
Ne
β2n ?25
Ne
 ?
28
F
91928.035860(130)46 zsn27
F
(4−)
29
F
92029.043100(560)2.5(3) msβn (60(40)%)28
Ne
(5/2+)
β (40(40)%)29
Ne
β2n ?27
Ne
 ?
30
F
[6]
92130.05256(54)#0.96+0.56
−0.41
 zs
n29
F
31
F
92231.06020(570)#2 ms# [> 260 ns]β ?31
Ne
 ?
5/2+#
βn ?30
Ne
 ?
β2n ?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. Intermediate product of various CNO cycles in stellar nucleosynthesis as part of the process producing helium from hydrogen
  9. 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 second lightest unstable nuclide (after beryllium-8, with 4 protons and 4 neutrons) with equal numbers of protons and neutrons and lightest such with an odd atomic number, having 9 of each. (See also the parity discussion of nuclide stability.) [7]

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.

Isomers

Only two nuclear isomers (long-lived excited nuclear states), fluorine-18m and fluorine-26m, have been characterized. The half-life of 18m
F
before it undergoes isomeric transition is 162(7)  nanoseconds . This is less than the decay half-life of any of the particle-bound fluorine radioisotope nuclear ground states. 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.

See also

Daughter products other than fluorine

References

  1. 1 2 3 4 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.
  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. 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.
  5. 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.
  6. 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). arXiv: 2407.19303 . doi: 10.1103/PhysRevLett.133.082501 . ISSN   0031-9007.
  7. National Nuclear Data Center. "NuDat 3.0 database". Brookhaven National Laboratory.

Sources