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Isotopes of oxygen

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Isotopesofoxygen(8O)
Main isotopes Decay
abun­dance half-life(t1/2) mode pro­duct
15O trace 122.266 s β+100% 15N
16O 99.8% stable
17O 0.0380% stable
18O 0.205% stable
Standard atomic weightAr°(O)

There are three known stableisotopesofoxygen(8O):16
O
,17
O
,and18
O
.

Radioactive isotopesranging from11
O
to28
O
have also been characterized, all short-lived. The longest-lived radioisotope is15
O
with ahalf-lifeof122.266(43)s,while the shortest-lived isotope is theunbound11
O
with a half-life of198(12)yoctoseconds,though half-lives have not been measured for the unbound heavy isotopes27
O
and28
O
.[3]

List of isotopes[edit]

Nuclide
[n 1] 		Z N Isotopic mass(Da)[4]
[n 2] 		Half-life[5]

[resonance width] 		Decay
mode[5]
[n 3] 		Daughter
isotope
[n 4] 		Spinand
parity[5]
[n 5][n 6] 		Natural abundance(mole fraction)
Excitation energy Normal proportion[5] Range of variation
11
O
[6] 		8 3 11.05125(6) 198(12) ys
[2.31(14)MeV] 		2p 9
C
 		(3/2−)
12
O
 		8 4 12.034368(13) 8.9(3.3) zs 2p 10
C
 		0+
13
O
 		8 5 13.024815(10) 8.58(5) ms β+(89.1(2)%) 13
N
 		(3/2−)
β+p (10.9(2)%) 12
C
β+p,α (<0.1%) 24
He
[7]
14
O
 		8 6 14.008596706(27) 70.621(11) s β+ 14
N
 		0+
15
O
[n 7] 		8 7 15.0030656(5) 122.266(43) s β+ 15
N
 		1/2− Trace[8]
16
O
[n 8] 		8 8 15.994914619257(319) Stable 0+ [0.99738,0.99776][9]
17
O
[n 9] 		8 9 16.999131755953(692) Stable 5/2+ [0.000367,0.000400][9]
18
O
[n 8][n 10] 		8 10 17.999159612136(690) Stable 0+ [0.00187,0.00222][9]
19
O
 		8 11 19.0035780(28) 26.470(6) s β− 19
F
 		5/2+
20
O
 		8 12 20.0040754(9) 13.51(5) s β− 20
F
 		0+
21
O
 		8 13 21.008655(13) 3.42(10) s β− 21
F
 		(5/2+)
β−n?[n 11] 20
F
?
22
O
 		8 14 22.00997(6) 2.25(9) s β−(>78%) 22
F
 		0+
β−n (<22%) 21
F
23
O
 		8 15 23.01570(13) 97(8) ms β−(93(2)%) 23
F
 		1/2+
β−n (7(2)%) 22
F
24
O
[n 12] 		8 16 24.01986(18) 77.4(4.5) ms β−(57(4)%) 24
F
 		0+
β−n (43(4)%) 23
F
25
O
 		8 17 25.02934(18) 5.18(35) zs n 24
O
 		3/2+#
26
O
 		8 18 26.03721(18) 4.2(3.3) ps 2n 24
O
 		0+
27
O
[3] 		8 19 ≥2.5 zs n 26
O
 		(3/2+, 7/2−)
28
O
[3] 		8 20 ≥650 ys 2n 26
O
 		0+
This table header & footer:
  1. ^mO – Excitednuclear isomer.
  2. ^( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ^ Modes of decay:
    n: Neutron emission
    p: Proton emission
  4. ^Bold symbolas daughter – Daughter product is stable.
  5. ^( ) spin value – Indicates spin with weak assignment arguments.
  6. ^# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  7. ^Intermediate product ofCNO-Iinstellar nucleosynthesisas part of the process producing helium from hydrogen
  8. ^abThe ratio between16
    O
    and18
    O
    is used todeduce ancient temperatures.
  9. ^Can be used in NMR studies of metabolic pathways.
  10. ^Can be used in studying certain metabolic pathways.
  11. ^Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.
  12. ^Heaviest particle-bound isotope of oxygen, seeNuclear drip line

Stable isotopes[edit]

Late in a massive star's life,16
O
concentrates in the N-shell,17
O
in the H-shell and18
O
in the He-shell.

Natural oxygen is made of three stableisotopes,16
O
,17
O
,and18
O
,with16
O
being the most abundant (99.762%natural abundance). Depending on the terrestrial source, the standard atomic weight varies within the range of [15.99903,15.99977] (theconventional valueis 15.999).

16
O
has high relative and absolute abundance because it is a principal product ofstellar evolutionand because it is a primary isotope, meaning it can be made bystarsthat were initiallyhydrogenonly.[10]Most16
O
issynthesizedat the end of thehelium fusionprocess instars;thetriple- Alpha processcreates12
C
,which captures an additional4
He
nucleus to produce16
O
.Theneon burning processcreates additional16
O
.[10]

Both17
O
and18
O
are secondary isotopes, meaning their synthesis requires seed nuclei.17
O
is primarily made by burning hydrogen into helium in theCNO cycle,making it a common isotope in the hydrogen burning zones of stars.[10]Most18
O
is produced when14
N
(made abundant from CNO burning) captures a4
He
nucleus, becoming18
F
.This quickly (half-life around 110 minutes)beta decaysto18
O
making that isotope common in the helium-rich zones of stars.[10]About 109kelvinis needed tofuseoxygen intosulfur.[11]

An atomic mass of 16 was assigned to oxygen prior to the definition of the unifiedatomic mass unitbased on12
C
.[12]Since physicists referred to16
O
only, while chemists meant the natural mix of isotopes, this led to slightly different mass scales.

Applications of various isotopes[edit]

Measurements of18O/16O ratioare often used to interpret changes inpaleoclimate.Oxygen in Earth's air is99.759%16
O
,0.037%17
O
and0.204%18
O
.[13]Watermolecules with a lighter isotope are slightly more likely toevaporateand less likely to fall asprecipitation,[14]so Earth's freshwater and polar ice have slightly less (0.1981%)18
O
than air (0.204%) orseawater(0.1995%). This disparity allows analysis of temperature patterns via historicice cores.

Solid samples (organic and inorganic) for oxygen isotopic ratios are usually stored in silver cups and measured withpyrolysisandmass spectrometry.[15]Researchers need to avoid improper or prolonged storage of the samples for accurate measurements.[15]

Due to natural oxygen being mostly16
O,samples enriched with the other stable isotopes can be used forisotope labeling.For example, it was proven, that the oxygen released inphotosynthesisoriginates inH2O,rather than in the also consumed CO2,by isotope tracing experiments. The oxygen contained in CO2in turn is used to make up the sugars formed by photosynthesis.

Inheavy water reactorstheneutron moderatorshould preferably be low in17
Oand18
Odue to their higher neutron absorption cross section compared to16
O.While this effect can also be observed inlight water reactors,ordinary hydrogen (protium) has a higher absorption cross section than any stable isotope of oxygen and its number density is twice as high in water as that of oxygen so that the effect is negligible. As some methods ofisotope separationenrich not only heavier isotopes of hydrogen but also heavier isotopes of oxygen when producingheavy water,the concentration of17
Oand18
Ocan be measurably higher. Furthermore, the17
O(n,α)14
Creaction is a further undesirable result of an elevated concentration of heavier isotopes of oxygen. Therefore, facilities which removetritiumfrom heavy water used in nuclear reactors often also remove or at least reduce the amount of heavier isotopes of oxygen.

Oxygen isotopes are also used to trace ocean composition and temperature whichseafoodis from.[16]

Radioisotopes[edit]

Thirteenradioisotopeshave been characterized; the most stable are15
O
withhalf-life122.266(43) sand14
O
with half-life70.621(11) s.All remaining radioisotopes have half-lives less than27 sand most have half-lives less than 0.1 s. The four heaviest known isotopes (up to28
O
) decay byneutron emissionto 24
O
,whose half-life is77.4(4.5) ms.This isotope, along with28Ne,have been used in the model of reactions in crust of neutron stars.[17]The most commondecay modefor isotopes lighter than the stable isotopes isβ+decaytonitrogen,and the most common mode after isβ−decaytofluorine.

Oxygen-13[edit]

Oxygen-13 is an unstableisotope,with 8 protons and 5 neutrons. It has spin 3/2−, andhalf-life8.58(5)ms.Its atomic mass is13.024815(10)Da.It decays tonitrogen-13by electron capture, with a decay energy of17.770(10)MeV.Its parent nuclide isfluorine-14.

Oxygen-14[edit]

Oxygen-14 is the second most stable radioisotope. Oxygen-14ion beamsare of interest to researchers of proton-rich nuclei; for example, one early experiment at theFacility for Rare Isotope BeamsinEast Lansing, Michigan,used a14O beam to study thebeta decay transitionof this isotope to14N.[18][19]

Oxygen-15[edit]

Oxygen-15 is a radioisotope, often used inpositron emission tomography(PET). It can be used in, among other things,waterfor PETmyocardial perfusion imagingand forbrainimaging.[20][21]It has an atomic mass of15.0030656(5),and ahalf-lifeof122.266(43) s.It is produced throughdeuteronbombardment ofnitrogen-14using acyclotron.[22]

14
N
+2
H
→15
O
+ n

Oxygen-15 and nitrogen-13 are produced in air whengamma rays(for example fromlightning) knock neutrons out of16O and14N:[23]

16
O
+ γ →15
O
+ n
14
N
+ γ →13
N
+ n

15
O
decays to15
N
,emitting apositron.The positron quickly annihilates with an electron, producing two gamma rays of about 511 keV. After a lightning bolt, this gamma radiation dies down with half-life of 2 minutes, but these low-energy gamma rays go on average only about 90 metres through the air. Together with rays produced from positrons from nitrogen-13 they may only be detected for a minute or so as the "cloud" of15
O
and13
N
floats by, carried by the wind.[8]

Oxygen-20[edit]

Oxygen-20 has a half-life of13.51±0.05 sand decays by β−decay to20F. It is one of the knowncluster decayejected particles, being emitted in the decay of228Thwith a branching ratio of about(1.13±0.22)×10−13.[24]

See also[edit]

References[edit]

  1. ^"Standard Atomic Weights: Oxygen".CIAAW.2009.
  2. ^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.ISSN1365-3075.
  3. ^abcKondo, Y.; Achouri, N. L.; Falou, H. Al; et al. (2023-08-30)."First observation of 28O".Nature.620(7976). Springer Science and Business Media LLC: 965–970.Bibcode:2023Natur.620..965K.doi:10.1038/s41586-023-06352-6.ISSN0028-0836.PMC10630140.PMID37648757.
  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. ^abcdKondev, 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.
  6. ^Webb, T. B.; et al. (2019). "First Observation of Unbound11O, the Mirror of the Halo Nucleus11Li ".Physical Review Letters.122(12): 122501–1–122501–7.arXiv:1812.08880.Bibcode:2019PhRvL.122l2501W.doi:10.1103/PhysRevLett.122.122501.PMID30978039.S2CID84841752.
  7. ^Paleja, Ameya (2023-09-05)."Scientists observe nucleus decay into four particles".interestingengineering.Retrieved2023-09-29.
  8. ^abTeruaki Enoto; et al. (Nov 23, 2017). "Photonuclear reactions triggered by lightning discharge".Nature.551(7681): 481–484.arXiv:1711.08044.Bibcode:2017Natur.551..481E.doi:10.1038/nature24630.PMID29168803.S2CID4388159.
  9. ^abc"Atomic Weight of Oxygen | Commission on Isotopic Abundances and Atomic Weights".ciaaw.org.Retrieved2022-03-15.
  10. ^abcdB. S. Meyer (September 19–21, 2005)."Nucleosynthesis and galactic chemical evolution of the isotopes of oxygen"(PDF).Proceedings of the NASA Cosmochemistry Program and the Lunar and Planetary Institute.Workgroup on Oxygen in the Earliest Solar System.Gatlinburg, Tennessee. 9022.
  11. ^Emsley 2001,p. 297.
  12. ^Parks & Mellor 1939,Chapter VI, Section 7.
  13. ^Cook & Lauer 1968,p. 500.
  14. ^Dansgaard, W (1964)."Stable isotopes in precipitation"(PDF).Tellus.16(4): 436–468.Bibcode:1964Tell...16..436D.doi:10.1111/j.2153-3490.1964.tb00181.x.
  15. ^abTsang, Man-Yin; Yao, Weiqi; Tse, Kevin (2020). Kim, Il-Nam (ed.)."Oxidized silver cups can skew oxygen isotope results of small samples".Experimental Results.1:e12.doi:10.1017/exp.2020.15.ISSN2516-712X.
  16. ^Martino, Jasmin C.; Trueman, Clive N.; Mazumder, Debashish; Crawford, Jagoda; Doubleday, Zoë A. (September 12, 2022)."Using 'chemical fingerprinting' to fight seafood fraud and illegal fishing".Fish and Fisheries.23(6).Phys.org:1455–1468.doi:10.1111/faf.12703.S2CID252173914.Archived from the original on September 13, 2022.RetrievedSeptember 13,2022.{{cite journal}}:CS1 maint: bot: original URL status unknown (link)
  17. ^Berry, D.K; Horowitz, C.J (April 2008)."Fusion of neutron rich oxygen isotopes in the crust of accreting neutron stars".Physical Review C.77(4): 045807.arXiv:0710.5714.Bibcode:2008PhRvC..77d5807H.doi:10.1103/PhysRevC.77.045807.S2CID118639621.
  18. ^"APS -Fall 2022 Meeting of the APS Division of Nuclear Physics - Event - Oxygen-14 Beam Production at 5 and 15 MeV/u with MARS Spectrometer".Bulletin of the American Physical Society.67(17). American Physical Society.
  19. ^Energy, US Department of."Researchers develop a novel method to study nuclear reactions on short-lived isotopes involved in explosions of stars".phys.org.Retrieved16 December2023.
  20. ^Rischpler, Christoph; Higuchi, Takahiro; Nekolla, Stephan G. (22 November 2014). "Current and Future Status of PET Myocardial Perfusion Tracers".Current Cardiovascular Imaging Reports.8(1): 333–343.doi:10.1007/s12410-014-9303-z.S2CID72703962.
  21. ^Kim, E. Edmund; Lee, Myung-Chul; Inoue, Tomio; Wong, Wai-Hoi (2012).Clinical PET and PET/CT: Principles and Applications.Springer. p. 182.ISBN9781441908025.
  22. ^"Production of PET Radionuclides".Austin Hospital, Austin Health. Archived fromthe originalon 15 January 2013.Retrieved6 December2012.
  23. ^Timmer, John (25 November 2017)."Lightning strikes leave behind a radioactive cloud".Ars Technica.
  24. ^ Bonetti, R.; Guglielmetti, A. (2007)."Cluster radioactivity: an overview after twenty years"(PDF).Romanian Reports in Physics.59:301–310. Archived fromthe original(PDF)on 19 September 2016.
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