Isotopes of krypton
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Standard atomic weight Ar°(Kr) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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There are 33 known isotopes of krypton (36Kr) with atomic mass numbers from 69 through 101.[5] Naturally occurring krypton is made of five stable isotopes and one which is slightly radioactive with an extremely long half-life, plus traces of radioisotopes that are produced by cosmic rays in the atmosphere.
The spectral signature of krypton can be observed to have several very sharp lines. When krypton is placed into an electric discharge tube, it emits visible light with a distinctive orange-red color.
Notable isotopes
Krypton-86
Krypton-86 was formerly used to define the meter from 1960 until 1983, when the definition of the meter was based on the wavelength of the 605 nm (orange) spectral line of a krypton-86 atom.
Krypton-81
Radioactive krypton-81 is the product of reactions with cosmic rays that strike the atmosphere, along with some of the other isotopes of krypton. Krypton-81 has a half-life of about 229,000 years.
Krypton-81 has been used for dating old (50,000- to 800,000-year-old) groundwater.[6]
Krypton-85
Krypton-85 is a radioisotope of krypton that has a half-life of about 10.75 years. This isotope is produced by the nuclear fission of uranium and plutonium in nuclear weapons testing and in nuclear reactors, as well as by cosmic rays. An important goal of the Limited Nuclear Test Ban Treaty of 1963 was to eliminate the release of such radioisotopes into the atmosphere, and since 1963 much of that krypton-85 has had time to decay. However, it is inevitable that krypton-85 is released during the reprocessing of fuel rods from nuclear reactors.
Atmospheric concentration
The atmospheric concentration of krypton-85 around the North Pole is about 30 percent higher than that at the Amundsen–Scott South Pole Station because nearly all of the world's nuclear reactors and all of its major nuclear reprocessing plants are located in the northern hemisphere, and also well-north of the equator.[7] To be more specific, those nuclear reprocessing plants with significant capacities are located in the United States, the United Kingdom, the French Republic, the Russian Federation, Mainland China (PRC), Japan, India, and Pakistan.
Others
All of the other radioisotopes of krypton have half-lives of less than one day, except for krypton-79, which has a half-life of about 35.0 hours. This isotope decays by the emission of positrons and thus becoming bromine.
Table of isotopes
nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life | decay mode(s)[8][n 1] |
daughter isotope(s)[n 2] |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
---|---|---|---|---|---|---|---|---|---|
excitation energy | |||||||||
69Kr | 36 | 33 | 68.96518(43)# | 32(10) ms | β+ | 69Br | 5/2−# | ||
70Kr | 36 | 34 | 69.95526(41)# | 52(17) ms | β+ | 70Br | 0+ | ||
71Kr | 36 | 35 | 70.94963(70) | 100(3) ms | β+ (94.8%) | 71Br | (5/2)− | ||
β+, p (5.2%) | 70Se | ||||||||
72Kr | 36 | 36 | 71.942092(9) | 17.16(18) s | β+ | 72Br | 0+ | ||
73Kr | 36 | 37 | 72.939289(7) | 28.6(6) s | β+ (99.32%) | 73Br | 3/2− | ||
β+, p (.68%) | 72Se | ||||||||
73mKr | 433.66(12) keV | 107(10) ns | (9/2+) | ||||||
74Kr | 36 | 38 | 73.9330844(22) | 11.50(11) min | β+ | 74Br | 0+ | ||
75Kr | 36 | 39 | 74.930946(9) | 4.29(17) min | β+ | 75Br | 5/2+ | ||
76Kr | 36 | 40 | 75.925910(4) | 14.8(1) h | β+ | 76Br | 0+ | ||
77Kr | 36 | 41 | 76.9246700(21) | 74.4(6) min | β+ | 77Br | 5/2+ | ||
78Kr[n 3] | 36 | 42 | 77.9203648(12) | 9.2 +5.5 −2.6 ±1.3×1021 y[2] |
Double EC | 78Se | 0+ | 0.00355(3) | |
79Kr | 36 | 43 | 78.920082(4) | 35.04(10) h | β+ | 79Br | 1/2− | ||
79mKr | 129.77(5) keV | 50(3) s | 7/2+ | ||||||
80Kr | 36 | 44 | 79.9163790(16) | Stable | 0+ | 0.02286(10) | |||
81Kr[n 4] | 36 | 45 | 80.9165920(21) | 2.29(11)×105 y | EC | 81Br | 7/2+ | trace | |
81mKr | 190.62(4) keV | 13.10(3) s | IT (99.975%) | 81Kr | 1/2− | ||||
EC (.025%) | 81Br | ||||||||
82Kr | 36 | 46 | 81.9134836(19) | Stable | 0+ | 0.11593(31) | |||
83Kr[n 5] | 36 | 47 | 82.914136(3) | Stable | 9/2+ | 0.11500(19) | |||
83m1Kr | 9.4053(8) keV | 154.4(11) ns | 7/2+ | ||||||
83m2Kr | 41.5569(10) keV | 1.83(2) h | IT | 83Kr | 1/2− | ||||
84Kr[n 5] | 36 | 48 | 83.911507(3) | Stable | 0+ | 0.56987(15) | |||
84mKr | 3236.02(18) keV | 1.89(4) µs | 8+ | ||||||
85Kr[n 5] | 36 | 49 | 84.9125273(21) | 10.776(3) y | β− | 85Rb | 9/2+ | trace | |
85m1Kr | 304.871(20) keV | 4.480(8) h | β− (78.6%) | 85Rb | 1/2− | ||||
IT (21.4%) | 85Kr | ||||||||
85m2Kr | 1991.8(13) keV | 1.6(7) µs [1.2(+10-4) µs] |
(17/2+) | ||||||
86Kr[n 6][n 5] | 36 | 50 | 85.91061073(11) | Observationally Stable[n 7] | 0+ | 0.17279(41) | |||
87Kr | 36 | 51 | 86.91335486(29) | 76.3(5) min | β− | 87Rb | 5/2+ | ||
88Kr | 36 | 52 | 87.914447(14) | 2.84(3) h | β− | 88Rb | 0+ | ||
89Kr | 36 | 53 | 88.91763(6) | 3.15(4) min | β− | 89Rb | 3/2(+#) | ||
90Kr | 36 | 54 | 89.919517(20) | 32.32(9) s | β− | 90mRb | 0+ | ||
91Kr | 36 | 55 | 90.92345(6) | 8.57(4) s | β− | 91Rb | 5/2(+) | ||
92Kr | 36 | 56 | 91.926156(13) | 1.840(8) s | β− (99.96%) | 92Rb | 0+ | ||
β−, n (.033%) | 91Rb | ||||||||
93Kr | 36 | 57 | 92.93127(11) | 1.286(10) s | β− (98.05%) | 93Rb | 1/2+ | ||
β−, n (1.95%) | 92Rb | ||||||||
94Kr | 36 | 58 | 93.93436(32)# | 210(4) ms | β− (94.3%) | 94Rb | 0+ | ||
β−, n (5.7%) | 93Rb | ||||||||
95Kr | 36 | 59 | 94.93984(43)# | 114(3) ms | β− | 95Rb | 1/2(+) | ||
96Kr | 36 | 60 | 95.94307(54)# | 80(7) ms | β− | 96Rb | 0+ | ||
97Kr | 36 | 61 | 96.94856(54)# | 63(4) ms | β− | 97Rb | 3/2+# | ||
β−, n | 96Rb | ||||||||
98Kr | 36 | 62 | 97.95191(64)# | 46(8) ms | 0+ | ||||
99Kr | 36 | 63 | 98.95760(64)# | 40(11) ms | (3/2+)# | ||||
100Kr | 36 | 64 | 99.96114(54)# | 10# ms [>300 ns] |
0+ | ||||
101Kr [n 8] | 36 | 65 | unknown | >635 ns | β−, 2n | 99Rb | unknown | ||
β−, n | 100Rb | ||||||||
β− | 101Rb |
- ^ Abbreviations:
EC: Electron capture
IT: Isomeric transition - ^ Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)
- ^ Primordial radionuclide
- ^ Used to date groundwater
- ^ a b c d Fission product
- ^ Formerly used to define the meter
- ^ Believed to decay by β−β− to 86Sr
- ^ New isotope.
Notes
- The isotopic composition refers to that in air.
- Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
- Commercially available materials may have been subjected to an undisclosed or inadvertent isotopic fractionation. Substantial deviations from the given mass and composition can occur.
- Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
- Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.
References
- ^ 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.
- ^ a b Patrignani, C.; et al. (Particle Data Group) (2016). "Review of Particle Physics". Chinese Physics C. 40 (10): 100001. Bibcode:2016ChPhC..40j0001P. doi:10.1088/1674-1137/40/10/100001. See p. 768 Cite error: The named reference "Patrignani2016" was defined multiple times with different content (see the help page).
- ^ "Standard Atomic Weights: Krypton". CIAAW. 2001.
- ^ 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.
- ^ "Chart of Nuclides". Brookhaven National Laboratory.
- ^ N. Thonnard; L. D. MeKay; T. C. Labotka (2001). "Development of Laser-Based Resonance Ionization Techniques for 81-Kr and 85-Kr Measurements in the Geosciences" (PDF). University of Tennessee, Institute for Rare Isotope Measurements. pp. 4–7.
- ^ "Resources on Isotopes". U.S. Geological Survey. Retrieved 2007-03-20.
- ^ "Universal Nuclide Chart". nucleonica.
{{cite web}}
: Unknown parameter|registration=
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suggested) (help)
- Isotope masses from:
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
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: Unknown parameter|deadurl=
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suggested) (help)
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
- Isotopic compositions and standard atomic masses from:
- J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
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: Unknown parameter|laysummary=
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- Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
{{cite journal}}
: Unknown parameter|deadurl=
ignored (|url-status=
suggested) (help) - National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
{{cite web}}
: Check date values in:|accessdate=
(help) - N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide (ed.). CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.
{{cite book}}
: Unknown parameter|nopp=
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suggested) (help)
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.