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Standard atomic weight Ar°(F) | ||||||||||||||||||||||||||
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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.
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.
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] | 9 | 4 | 13.045120(540)# | p ? | 12 O | 1/2+# | |||||||||||||
14 F | 9 | 5 | 14.034320(40) | 500(60) ys [910(100) keV] | p ? | 13 O | 2− | ||||||||||||
15 F | 9 | 6 | 15.017785(15) | 1.1(3) zs [376 keV] | p | 14 O | 1/2+ | ||||||||||||
16 F | 9 | 7 | 16.011460(6) | 21(5) zs [21.3(5.1) keV] | p | 15 O | 0− | ||||||||||||
17 F [n 8] | 9 | 8 | 17.00209524(27) | 64.370(27) s | β+ | 17 O | 5/2+ | ||||||||||||
18 F [n 9] | 9 | 9 | 18.0009373(5) | 109.734(8) min | β+ | 18 O | 1+ | Trace | |||||||||||
18m F | 1121.36(15) keV | 162(7) ns | IT | 18 F | 5+ | ||||||||||||||
19 F | 9 | 10 | 18.998403162067(883) | Stable | 1/2+ | 1 | |||||||||||||
20 F | 9 | 11 | 19.99998125(3) | 11.0062(80) s | β− | 20 Ne | 2+ | ||||||||||||
21 F | 9 | 12 | 20.9999489(19) | 4.158(20) s | β− | 21 Ne | 5/2+ | ||||||||||||
22 F | 9 | 13 | 22.002999(13) | 4.23(4) s | β− (> 89%) | 22 Ne | (4+) | ||||||||||||
β−n (< 11%) | 21 Ne | ||||||||||||||||||
23 F | 9 | 14 | 23.003530(40) | 2.23(14) s | β− (> 86%) | 23 Ne | 5/2+ | ||||||||||||
β−n (< 14%) | 22 Ne | ||||||||||||||||||
24 F | 9 | 15 | 24.008100(100) | 384(16) ms | β− (> 94.1%) | 24 Ne | 3+ | ||||||||||||
β−n (< 5.9%) | 23 Ne | ||||||||||||||||||
25 F | 9 | 16 | 25.012170(100) | 80(9) ms | β− (76.9(4.5)%) | 25 Ne | (5/2+) | ||||||||||||
β−n (23.1(4.5)%) | 24 Ne | ||||||||||||||||||
β−2n ? | 23 Ne ? | ||||||||||||||||||
26 F | 9 | 17 | 26.020050(110) | 8.2(9) ms | β− (86.5(4.0)%) | 26 Ne | 1+ | ||||||||||||
β−n (13.5(4.0)%) | 25 Ne | ||||||||||||||||||
β−2n ? | 24 Ne ? | ||||||||||||||||||
26m F | 643.4(1) keV | 2.2(1) ms | IT (82(11)%) | 26 F | (4+) | ||||||||||||||
β−n (12(8)%) | 25 Ne | ||||||||||||||||||
β− ? | 26 Ne ? | ||||||||||||||||||
27 F | 9 | 18 | 27.026980(130) | 5.0(2) ms | β−n (77(21)%) | 26 Ne | 5/2+# | ||||||||||||
β− (23(21)%) | 27 Ne | ||||||||||||||||||
β−2n ? | 25 Ne ? | ||||||||||||||||||
28 F | 9 | 19 | 28.035860(130) | 46 zs | n | 27 F | (4−) | ||||||||||||
29 F | 9 | 20 | 29.043100(560) | 2.5(3) ms | β−n (60(40)%) | 28 Ne | (5/2+) | ||||||||||||
β− (40(40)%) | 29 Ne | ||||||||||||||||||
β−2n ? | 27 Ne ? | ||||||||||||||||||
30 F [6] | 9 | 21 | 30.05256(54)# | 0.96+0.56 −0.41 zs | n | 29 F | |||||||||||||
31 F | 9 | 22 | 31.06020(570)# | 2 ms# [> 260 ns] | β− ? | 31 Ne ? | 5/2+# | ||||||||||||
β−n ? | 30 Ne ? | ||||||||||||||||||
β−2n ? | 29 Ne ? | ||||||||||||||||||
This table header & footer: |
EC: | Electron capture |
IT: | Isomeric transition |
n: | Neutron emission |
p: | Proton emission |
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 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.
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.
Daughter products other than fluorine