Isotopes of krypton

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Isotopes of krypton (36Kr)
Main isotopes[1] Decay
abun­dance half-life (t1/2) mode pro­duct
78Kr 0.360% 9.2×1021 y[2] εε
78Se
79Kr synth 35 h ε
79Br
β+
 		79Br
γ
 		–
80Kr 2.29%
stable
81Kr trace 2.3×105 y ε
81Br
81mKr synth 13.10 s
IT
 		81Kr
ε 81Br
82Kr 11.6% stable
83Kr 11.5% stable
84Kr 57.0% stable
85Kr trace 11 y
β−
85Rb
86Kr 17.3% stable
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    • There are 34 known

    cosmic rays in the atmosphere
    .

    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 energy Normal proportion Range of variation
    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 10] 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 11] 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 12] 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 12] 36 48 83.911507(3) Stable 0+ 0.56987(15)
    84mKr 3236.02(18) keV 1.89(4) µs 8+
    85Kr[n 12] 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 13][n 12] 36 50 85.91061073(11)
    Observationally Stable[n 14]
    		 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[n 12] 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[n 12] 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 95.942998(62)[7] 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 36 65 unknown >635 ns β−, 2n 99Rb unknown
    β−, n 100Rb
    β− 101Rb
    102Kr[8] 36 66 0+
    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. age of universe
      .
    5. ^ a b # – 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. ^
      Fission product
    13. ^ Formerly used to define the meter
    14. ^ Believed to decay by β−β− to 86Sr
    • The isotopic composition refers to that in air.

    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)

    aquitards with very low hydraulic conductivity.[10]

    Krypton-85

    Main article: Krypton-85

    Krypton-85 has a half-life of about 10.75 years. This isotope is produced by the

    fuel rods from nuclear reactors.[citation needed
    ]

    Atmospheric concentration

    See also: Nuclear reprocessing

    The atmospheric concentration of krypton-85 around the

    northern hemisphere, and also well-north of the equator.[11]
    To be more specific, those
    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.

    References

    1. doi:10.1088/1674-1137/abddae
      .
    2. ^ a b Patrignani, C.; et al. (
      doi:10.1088/1674-1137/40/10/100001
      .       See p. 768
    3. ^ "Standard Atomic Weights: Krypton". CIAAW. 2001.
    4. ISSN 1365-3075
      .
    5. ^ "Chart of Nuclides". Brookhaven National Laboratory. Archived from the original on 2017-10-18. Retrieved 2011-11-21.
    6. S2CID 234019083
      .
    7. S2CID 220512482
      .
    8. S2CID 234019083
      .
    9. 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).
      doi:10.2172/809813
      .
    11. U.S. Geological Survey. Archived from the original
      on 2001-09-24. Retrieved 2007-03-20.
    12. doi:10.1364/AO.2.000455
      .

    Sources

    External links
    Retrieved from "https://en.wikipedia.org/w/index.php?title=Isotopes_of_krypton&oldid=1216375678"