Isotopes of krypton

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Isotopes of krypton  (36Kr)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
78Kr0.360%9.2×1021 y [2] εε 78Se
79Kr synth 35 h ε 79Br
β+ 79Br
γ –
80Kr2.29% stable
81Kr trace 2.3×105 yε 81Br
81mKrsynth13.10 s IT 81Kr
ε81Br
82Kr11.6%stable
83Kr11.5%stable
84Kr57.0%stable
85Kr trace11 y β− 85Rb
86Kr17.3%stable
Standard atomic weight Ar°(Kr)

There are 34 known isotopes of krypton (36Kr) with atomic mass numbers from 69 through 102. [5] [6] Naturally occurring krypton is made of five stable isotopes and one (78
Kr
) which is slightly radioactive with an extremely long half-life, plus traces of radioisotopes that are produced by cosmic rays in the atmosphere.

Contents

List of isotopes

Nuclide
[n 1] 		Z N Isotopic mass (Da)
[n 2] [n 3] 		Half-life
[n 4] [n 5] 		Decay
mode
[n 6] 		Daughter
isotope
[n 7] [n 8] 		Spin and
parity
[n 9] [n 5] 		Natural abundance (mole fraction)
Excitation energyNormal proportionRange of variation
69Kr363368.96518(43)#32(10) ms β+ 69Br5/2−#
70Kr363469.95526(41)#52(17) msβ+70Br0+
71Kr363570.94963(70)100(3) msβ+ (94.8%)71Br(5/2)−
β+, p (5.2%)70Se
72Kr363671.942092(9)17.16(18) sβ+72Br0+
73Kr363772.939289(7)28.6(6) sβ+ (99.32%)73Br3/2−
β+, p (.68%)72Se
73mKr433.66(12) keV107(10) ns(9/2+)
74Kr363873.9330844(22)11.50(11) minβ+74Br0+
75Kr363974.930946(9)4.29(17) minβ+75Br5/2+
76Kr364075.925910(4)14.8(1) hβ+76Br0+
77Kr364176.9246700(21)74.4(6) minβ+77Br5/2+
78Kr [n 10] 364277.9203648(12)9.2 +5.5
−2.6±1.3×1021 y [2] 		Double EC 78Se0+0.00355(3)
79Kr364378.920082(4)35.04(10) hβ+79Br1/2−
79mKr129.77(5) keV50(3) s7/2+
80Kr364479.9163790(16)Stable0+0.02286(10)
81Kr [n 11] 364580.9165920(21)2.29(11)×105 y EC 81Br7/2+trace
81mKr190.62(4) keV13.10(3) s IT (99.975%)81Kr1/2−
EC (.025%)81Br
82Kr364681.9134836(19)Stable0+0.11593(31)
83Kr [n 12] 364782.914136(3)Stable9/2+0.11500(19)
83m1Kr9.4053(8) keV154.4(11) ns7/2+
83m2Kr41.5569(10) keV1.83(2) hIT83Kr1/2−
84Kr [n 12] 364883.911507(3)Stable0+0.56987(15)
84mKr3236.02(18) keV1.89(4) µs8+
85Kr [n 12] 364984.9125273(21)10.776(3) yβ−85Rb9/2+trace
85m1Kr304.871(20) keV4.480(8) hβ− (78.6%)85Rb1/2−
IT (21.4%)85Kr
85m2Kr1991.8(13) keV1.6(7) µs
[1.2(+10-4) µs]		(17/2+)
86Kr [n 13] [n 12] 365085.91061073(11) Observationally Stable [n 14] 0+0.17279(41)
87Kr365186.91335486(29)76.3(5) minβ−87Rb5/2+
88Kr365287.914447(14)2.84(3) hβ−88Rb0+
89Kr [n 12] 365388.91763(6)3.15(4) minβ−89Rb3/2(+#)
90Kr365489.919517(20)32.32(9) sβ−90mRb0+
91Kr365590.92345(6)8.57(4) sβ−91Rb5/2(+)
92Kr [n 12] 365691.926156(13)1.840(8) sβ− (99.96%)92Rb0+
β−, n (.033%)91Rb
93Kr365792.93127(11)1.286(10) sβ− (98.05%)93Rb1/2+
β−, n (1.95%)92Rb
94Kr365893.93436(32)#210(4) msβ− (94.3%)94Rb0+
β−, n (5.7%)93Rb
95Kr365994.93984(43)#114(3) msβ−95Rb1/2(+)
96Kr366095.942998(62) [7] 80(7) msβ−96Rb0+
97Kr366196.94856(54)#63(4) msβ−97Rb3/2+#
β−, n96Rb
98Kr366297.95191(64)#46(8) ms0+
99Kr366398.95760(64)#40(11) ms(3/2+)#
100Kr366499.96114(54)#10# ms
[>300 ns]		0+
101Kr3665unknown>635 nsβ−, 2n99Rbunknown
β−, n100Rb
β−101Rb
102Kr [8] 36660+
This table header & footer:
  1. ↑ mKr – 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. ↑ Bold half-life – nearly stable, half-life longer than age of universe.
  5. 1 2 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. ↑ Modes of decay:
    n: Neutron emission
  7. ↑ Bold italics symbol as daughter – Daughter product is nearly stable.
  8. ↑ Bold symbol as daughter – Daughter product is stable.
  9. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  10. ↑ Primordial radionuclide
  11. ↑ Used to date groundwater
  12. 1 2 3 4 5 6 Fission product
  13. ↑ Formerly used to define the meter
  14. ↑ Believed to decay by β−β− to 86Sr

Notable isotopes

Krypton-81

Radioactive krypton-81 is the product of spallation reactions with cosmic rays striking gases present in the Earth atmosphere, along with the six stable or nearly stable krypton isotopes. [9] Krypton-81 has a half-life of about 229,000 years.

Krypton-81 is used for dating ancient (50,000- to 800,000-year-old) groundwater and to determine their residence time in deep aquifers. One of the main technical limitations of the method is that it requires the sampling of very large volumes of water: several hundred liters or a few cubic meters of water. This is particularly challenging for dating pore water in deep clay aquitards with very low hydraulic conductivity. [10]

Krypton-85

Krypton-85 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.[ citation needed ]

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. [11] 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.

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 606 nm (orange) spectral line of a krypton-86 atom. [12]

Others

All other radioisotopes of krypton have half-lives of less than one day, except for krypton-79, a positron emitter with a half-life of about 35.0 hours.

Related Research Articles

<span class="mw-page-title-main">Isotopes of thallium</span> Nuclides with atomic number of 81 but with different mass numbers

Thallium (81Tl) has 41 isotopes with atomic masses that range from 176 to 216. 203Tl and 205Tl are the only stable isotopes and 204Tl is the most stable radioisotope with a half-life of 3.78 years. 207Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes. All isotopes of thallium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.

Naturally occurring platinum (78Pt) consists of five stable isotopes (192Pt, 194Pt, 195Pt, 196Pt, 198Pt) and one very long-lived (half-life 4.83×1011 years) radioisotope (190Pt). There are also 34 known synthetic radioisotopes, the longest-lived of which is 193Pt with a half-life of 50 years. All other isotopes have half-lives under a year, most under a day. All isotopes of platinum are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Platinum-195 is the most abundant isotope.

Natural hafnium (72Hf) consists of five observationally stable isotopes (176Hf, 177Hf, 178Hf, 179Hf, and 180Hf) and one very long-lived radioisotope, 174Hf, with a half-life of 7.0×1016 years. In addition, there are 34 known synthetic radioisotopes, the most stable of which is 182Hf with a half-life of 8.9×106 years. This extinct radionuclide is used in hafnium–tungsten dating to study the chronology of planetary differentiation.

Naturally occurring terbium (65Tb) is composed of one stable isotope, 159Tb. Thirty-seven radioisotopes have been characterized, with the most stable being 158Tb with a half-life of 180 years, 157Tb with a half-life of 71 years, and 160Tb with a half-life of 72.3 days. All of the remaining radioactive isotopes have half-lives that are less than 6.907 days, and the majority of these have half-lives that are less than 24 seconds. This element also has 27 meta states, with the most stable being 156m1Tb, 154m2Tb and 154m1Tb.

Naturally occurring gadolinium (64Gd) is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of 160Gd has never been observed; only a lower limit on its half-life of more than 1.3×1021 years has been set experimentally.

Promethium (61Pm) is an artificial element, except in trace quantities as a product of spontaneous fission of 238U and 235U and alpha decay of 151Eu, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. It was first synthesized in 1945.

Naturally occurring barium (56Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×1021 years (about 1011 times the age of the universe).

Indium (49In) consists of two primordial nuclides, with the most common (~ 95.7%) nuclide (115In) being measurably though weakly radioactive. Its spin-forbidden decay has a half-life of 4.41×1014 years, much longer than the currently accepted age of the Universe.

Natural palladium (46Pd) is composed of six stable isotopes, 102Pd, 104Pd, 105Pd, 106Pd, 108Pd, and 110Pd, although 102Pd and 110Pd are theoretically unstable. The most stable radioisotopes are 107Pd with a half-life of 6.5 million years, 103Pd with a half-life of 17 days, and 100Pd with a half-life of 3.63 days. Twenty-three other radioisotopes have been characterized with atomic weights ranging from 90.949 u (91Pd) to 128.96 u (129Pd). Most of these have half-lives that are less than a half an hour except 101Pd, 109Pd, and 112Pd.

Technetium (43Tc) is one of the two elements with Z < 83 that have no stable isotopes; the other such element is promethium. It is primarily artificial, with only trace quantities existing in nature produced by spontaneous fission or neutron capture by molybdenum. The first isotopes to be synthesized were 97Tc and 99Tc in 1936, the first artificial element to be produced. The most stable radioisotopes are 97Tc, 98Tc, and 99Tc.

Naturally occurring zirconium (40Zr) is composed of four stable isotopes (of which one may in the future be found radioactive), and one very long-lived radioisotope (96Zr), a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×1019 years; it can also undergo single beta decay, which is not yet observed, but the theoretically predicted value of t1/2 is 2.4×1020 years. The second most stable radioisotope is 93Zr, which has a half-life of 1.53 million years. Thirty other radioisotopes have been observed. All have half-lives less than a day except for 95Zr (64.02 days), 88Zr (83.4 days), and 89Zr (78.41 hours). The primary decay mode is electron capture for isotopes lighter than 92Zr, and the primary mode for heavier isotopes is beta decay.

Natural yttrium (39Y) is composed of a single isotope yttrium-89. The most stable radioisotopes are 88Y, which has a half-life of 106.6 days and 91Y with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except 87Y, which has a half-life of 79.8 hours, and 90Y, with 64 hours. The dominant decay mode below the stable 89Y is electron capture and the dominant mode after it is beta emission. Thirty-five unstable isotopes have been characterized.

Arsenic (33As) has 33 known isotopes and at least 10 isomers. Only one of these isotopes, 75As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is 73As with a half-life of 80 days. Arsenic has been proposed as a "salting" material for nuclear weapons. A jacket of 75As, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope 76As with a half-life of 1.0778 days and produce approximately 1.13 MeV gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several hours. Such a weapon is not known to have ever been built, tested, or used.

Germanium (32Ge) has five naturally occurring isotopes, 70Ge, 72Ge, 73Ge, 74Ge, and 76Ge. Of these, 76Ge is very slightly radioactive, decaying by double beta decay with a half-life of 1.78 × 1021 years (130 billion times the age of the universe).

Copper (29Cu) has two stable isotopes, 63Cu and 65Cu, along with 27 radioisotopes. The most stable radioisotope is 67Cu with a half-life of 61.83 hours, while the least stable is 54Cu with a half-life of approximately 75 ns. Most have half-lives under a minute. Unstable copper isotopes with atomic masses below 63 tend to undergo β+ decay, while isotopes with atomic masses above 65 tend to undergo β− decay. 64Cu decays by both β+ and β−.

Naturally occurring cobalt (27Co) consists of a single stable isotope, 59Co. Twenty-eight radioisotopes have been characterized; the most stable are 60Co with a half-life of 5.2714 years, 57Co, 56Co, and 58Co. All other isotopes have half-lives of less than 18 hours and most of these have half-lives of less than 1 second. This element also has 11 meta states, all of which have half-lives of less than 15 minutes.

Naturally occurring manganese (25Mn) is composed of one stable isotope, 55Mn. 26 radioisotopes have been characterized, with the most stable being 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.3 days, and 52Mn with a half-life of 5.591 days. All of the remaining radioactive isotopes have half-lives that are less than 3 hours and the majority of these have half-lives that are less than a minute. This element also has 3 meta states.

Naturally occurring chromium (24Cr) is composed of four stable isotopes; 50Cr, 52Cr, 53Cr, and 54Cr with 52Cr being the most abundant (83.789% natural abundance). 50Cr is suspected of decaying by β+β+ to 50Ti with a half-life of (more than) 1.8×1017 years. Twenty-two radioisotopes, all of which are entirely synthetic, have been characterized, the most stable being 51Cr with a half-life of 27.7 days. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority of these have half-lives that are less than 1 minute. This element also has two meta states, 45mCr, the more stable one, and 59mCr, the least stable isotope or isomer.

Naturally occurring vanadium (23V) is composed of one stable isotope 51V and one radioactive isotope 50V with a half-life of 2.71×1017 years. 24 artificial radioisotopes have been characterized (in the range of mass number between 40 and 65) with the most stable being 49V with a half-life of 330 days, and 48V with a half-life of 15.9735 days. All of the remaining radioactive isotopes have half-lives shorter than an hour, the majority of them below 10 seconds, the least stable being 42V with a half-life shorter than 55 nanoseconds, with all of the isotopes lighter than it, and none of the heavier, have unknown half-lives. In 4 isotopes, metastable excited states were found (including 2 metastable states for 60V), which adds up to 5 meta states.

Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-five radioisotopes have been characterized, with the most stable being 46Sc with a half-life of 83.8 days, 47Sc with a half-life of 3.35 days, and 48Sc with a half-life of 43.7 hours and 44Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound 39Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being 44m2Sc.

References

  1. ↑ 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. 1 2 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
  3. ↑ "Standard Atomic Weights: Krypton". CIAAW. 2001.
  4. ↑ 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.
  5. ↑ "Chart of Nuclides". Brookhaven National Laboratory. Archived from the original on 2017-10-18. Retrieved 2011-11-21.
  6. ↑ Sumikama, T.; et al. (2021). "Observation of new neutron-rich isotopes in the vicinity of Zr110". Physical Review C. 103 (1): 014614. Bibcode:2021PhRvC.103a4614S. doi:10.1103/PhysRevC.103.014614. hdl: 10261/260248 . S2CID   234019083.
  7. ↑ Smith, Matthew B.; Murböck, Tobias; Dunling, Eleanor; Jacobs, Andrew; Kootte, Brian; Lan, Yang; Leistenschneider, Erich; Lunney, David; Lykiardopoulou, Eleni Marina; Mukul, Ish; Paul, Stefan F.; Reiter, Moritz P.; Will, Christian; Dilling, Jens; Kwiatkowski, Anna A. (2020). "High-precision mass measurement of neutron-rich 96Kr". Hyperfine Interactions. 241 (1): 59. Bibcode:2020HyInt.241...59S. doi:10.1007/s10751-020-01722-2. S2CID   220512482.
  8. ↑ Sumikama, T.; et al. (2021). "Observation of new neutron-rich isotopes in the vicinity of Zr110". Physical Review C. 103 (1): 014614. Bibcode:2021PhRvC.103a4614S. doi:10.1103/PhysRevC.103.014614. hdl: 10261/260248 . S2CID   234019083.
  9. ↑ Leya, I.; Gilabert, E.; Lavielle, B.; Wiechert, U.; Wieler, W. (2004). "Production rates for cosmogenic krypton and argon isotopes in H-chondrites with known 36Cl-36Ar ages" (PDF). Antarctic Meteorite Research. 17: 185–199. Bibcode:2004AMR....17..185L.
  10. ↑ 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) (Report). University of Tennessee, Institute for Rare Isotope Measurements. pp. 4–7. doi:10.2172/809813.
  11. ↑ "Resources on Isotopes". U.S. Geological Survey. Archived from the original on 2001-09-24. Retrieved 2007-03-20.
  12. ↑ Baird, K. M.; Howlett, L. E. (1963). "The International Length Standard". Applied Optics . 2 (5): 455–463. Bibcode:1963ApOpt...2..455B. doi:10.1364/AO.2.000455.

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