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Isotopes of Selenium

List, data and properties of all known isotopes of Selenium as well as radioactive decay products and intermediate products.

 

Selenium isotopes

All atomic nuclei of the chemical element selenium are summarized under selenium isotopes; these all consist of an atomic nucleus with 34 protons and, in the uncharged state, 34 electrons. The difference between each selenium isotope is based on the number of neutrons in the nucleus.

 

Naturally Occurring Selenium Isotopes

Natural terrestrial selenium deposits are made up of six different isotopes which - with the exception of the quasi-stable selenium 82 - are considered to be stable.

Atomic Mass maQuantityHalf-lifeSpin
Selenium
Isotopic mixture
78,971 u100 %
Isotope 74Se73,9224759(1) u0,86(3) %stable0+
Isotope 76Se75,9192137(2) u9,23(7) %stable0+
Isotope 77Se76,9199142(5) u7,60(7) %stable1/2-
Isotope 78Se77,917309(2) u23,69(22) %stable0+
Isotope 80Se79,916522(8) u49,80(36) %stable0+
Isotope 82Se81,916700(9) u8,82(15) %9.39(17) × 1019 a0+

 

The average atomic mass can vary due to fluctuations in the isotopic composition of natural selenium.

 

Isotope Table: Selenium

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
64Se346430Selenium-6463.97134(54) u
[63.9526889 u]
{-26.69662 MeV}
0+
65Se346531Selenium-6564.96455(32) u
[64.9458989 u]
{-33.02146 MeV}
(3/2-)
66Se346632Selenium-6665.95528(21) u
[65.9366289 u]
{-41.65641 MeV}
0+
67Se346733Selenium-6766.94999(7) u
[66.9313389 u]
{-46.58401 MeV}
68Se346834Selenium-6867.9418252(5) u
[67.9231741 u]
{-54.18948 MeV}
0+
69Se346935Selenium-6968.9394148(16) u
[68.9207637 u]
{-56.43475 MeV}
1/2-
69m1Se346935Selenium-69m168.9394148(16) u
[68.9207637 u]
{-56.43475 MeV}
5/2-
69m2Se346935Selenium-69m268.9394148(16) u
[68.9207637 u]
{-56.43475 MeV}
9/2+
70Se347036Selenium-7069.9335155(17) u
[69.9148644 u]
{-61.92991 MeV}
0+70Br
71Se347137Selenium-7170.932209(3) u
[70.9135579 u]
{-63.14691 MeV}
(5/2-)71Br
71m1Se347137Selenium-71m170.932209(3) u
[70.9135579 u]
{-63.14691 MeV}
(1/2-)
71m2Se347137Selenium-71m270.932209(3) u
[70.9135579 u]
{-63.14691 MeV}
(9/2+)
72Se347238Selenium-7271.9271405(21) u
[71.9084894 u]
{-67.86819 MeV}
0+72Br
73Kr
73Se347339Selenium-7372.926755(8) u
[72.9081039 u]
{-68.22728 MeV}
9/2+0.87(5)73Br
73mSe347339Selenium-73m72.926755(8) u
[72.9081039 u]
{-68.22728 MeV}
3/2-
74Se347440Selenium-7473.9224759(1) u
[73.9038248 u]
{-72.21323 MeV}
0+74Br
74As
75Se347541Selenium-7574.92252287(8) u
[74.9038718 u]
{-72.16948 MeV}
5/2+0.67(4)75Br
76Se347642Selenium-7675.9192137(2) u
[75.9005626 u]
{-75.25195 MeV}
0+76Br
76As
77Se347743Selenium-7776.9199142(5) u
[76.9012631 u]
{-74.59944 MeV}
1/2-+0.53356(5)77Br
77As
77mSe347743Selenium-77m76.9199142(5) u
[76.9012631 u]
{-74.59944 MeV}
7/2+
78Se347844Selenium-7877.917309(2) u
[77.8986579 u]
{-77.02617 MeV}
0+78Br
78As
79Se347945Selenium-7978.91849925(24) u
[78.8998482 u]
{-75.91746 MeV}
7/2+- 1.018(15)79As
79mSe347945Selenium-79m78.91849925(24) u
[78.8998482 u]
{-75.91746 MeV}
1/2-
80Se348046Selenium-8079.916522(8) u
[79.8978709 u]
{-77.75926 MeV}
0+80As
80Br
81Se348147Selenium-8180.9179930(11) u
[80.8993419 u]
{-76.38903 MeV}
1/2-81As
81mSe348147Selenium-81m80.9179930(11) u
[80.8993419 u]
{-76.38903 MeV}
7/2+
82Se348248Selenium-8281.916700(9) u
[81.8980489 u]
{-77.59345 MeV}
0+82As
83Se348349Selenium-8382.919119(3) u
[82.9004679 u]
{-75.34017 MeV}
9/2+83As
83mSe348349Selenium-83m82.919119(3) u
[82.9004679 u]
{-75.34017 MeV}
1/2-
84Se348450Selenium-8483.9184668(21) u
[83.8998157 u]
{-75.94769 MeV}
0+84As
85As
85Se348551Selenium-8584.9222608(28) u
[84.9036097 u]
{-72.4136 MeV}
(5/2)+85As
86Se348652Selenium-8685.9243117(27) u
[85.9056606 u]
{-70.5032 MeV}
0+86As
87As
87Se348753Selenium-8786.9286886(24) u
[86.9100375 u]
{-66.42614 MeV}
(3/2+)
88Se348854Selenium-8887.931417(4) u
[87.9127659 u]
{-63.88465 MeV}
0+
89Se348955Selenium-8988.936669(4) u
[88.9180179 u]
{-58.99245 MeV}
(5/2+)
90Se349056Selenium-9089.94010(35) u
[89.9214489 u]
{-55.79649 MeV}
0+
91Se349157Selenium-9190.94570(46) u
[90.9270489 u]
{-50.58012 MeV}
92Se349258Selenium-9291.94984(43) u
[91.9311889 u]
{-46.72374 MeV}
0+
93Se349359Selenium-9392.95629(43) u
[92.9376389 u]
{-40.7156 MeV}
(1/2+)
94Se349460Selenium-9493.96049(54) u
[93.9418389 u]
{-36.80333 MeV}
0+
95Se349561Selenium-9594.96730(54) u
[94.9486489 u]
{-30.45985 MeV}

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
Se-64180 nsEC/β+64As100 %12.83(54) MeV
Se-6533(4) msEC/β+65As
EC, p → 64Ge

13.92(31) MeV
AL
Se-6642(12) msEC → 66As100 %10.37(20) MeVAL
Se-67136(12) msEC/β+67As
β+, p → 66Ge
99.5 %
0.5(1) %
10.01(7) MeV
AL
Se-6835.5(7) sEC/β+68As100 %4.7051(19) MeVAL
Se-6927.4(2) sEC/β+69As
EC, p → 68Ge
99.958 %
0.052(8) %
6.68(3) MeV
AL
Se-69m12.0(2) μs38.85(22) keV
Se-69m2960(23) ns574.0(4) keV
Se-7041.1(3) minEC/β+70As100 %2.41(5) MeVAL
Se-714.74(5) minEC/β+71As100 %4.747(5) MeVAL
Se-71m15.6(7) μs48.79(5) keV
Se-71m219.0(5) μs260.48(10) keV
Se-728.40(8) dEC → 72As100 %0.362(5) MeVAL
Se-737.15(9) hEC/β+73As100 %2.725(8) MeVAL
Se-73m39.8(17) minEC/β+73As
Iso → 73As
27.4(3) %
72.6(3) %

25.71(4) keVAL
Se-74stableAL
Se-75119.79(5) dEC → 75As100 %0.647(9) MeVAL
Se-76stableAL
Se-77stableAL
Se-77m17.36(5) sIso → 77Se100 %161.9223(10) keVAL
Se-78stableAL
Se-793.27(28) × 105 aβ-79Br100 %0.1506(10) MeVAL
Se-79m3.92(1) minβ-79Br
Iso → 79Se
0.056(11) %
99.944(11) %

95.77(3) keVAL
Se-80stable2 β-? AL
Se-8118.45(12) minβ-81Br100 %1.5880(14) MeVAL
Se-81m57.28(2) minβ-81Br
Iso → 81Se
0.051(14) %
99.949(14) %

103.00(6) keVAL
Se-829.39(17) × 1019 a-82Kr100 %AL
Se-8322.3(3) minβ-83Br100 %3.673(5) MeVAL
Se-83m70.1(4) sβ-83Br100 %228.92(7) keVAL
Se-843.26(10) minβ-84Br100 %1.835(26) MeVAL
Se-8532.9(3) sβ-85Br100 %6.162(4) MeVAL
Se-8614.3(3) sβ-86Br100 %5.129(4) MeVAL
Se-875.50(14) sβ-87Br
β-, n → 86Br
99.64 %
0.36(8) %
7.466(4) MeV
1.135(4) MeV
AL
Se-881.53(6) sβ-88Br
β-, n → 87Br
99.33 %
0.67(30) %
6.832(5) MeV
1.936(5) MeV
AL
Se-890.43(5) sβ-89Br
β-, n → 88Br
92.2(25) %
7.8(25) %
9.282(5) MeV
3.652(5) MeV
AL
Se-90195 msβ-90Br
β-, n → 89Br

?
8.20(33) MeV
4.40(33) MeV
AL
Se-910.27(5) sβ-91Br
β-, n → 90Br
79(10) %
21(10) %
10.53(43) MeV
5.35(43) MeV
AL
Se-92β-92Br100 %9.51(40) MeVAL
Se-93β-93Br100 %12.17(59) MeVAL
Se-94150 nsβ-94Br100 %10.60(58) MeVAL
Se-95392 nsβ-93Br
β-, n → 92Br
β-, 2n → 91Br
?
?
?
13.31(58) MeV

 

Notes (related to the columns):

1 - nuclide, isotope symbol.
2 - Z = number of protons (atomic number).
3 - Mass number A.
4 - N = number of neutrons.
5 - Identification of the Selenium isotope.
6 - Relative atomic mass of the Selenium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
7 - Nuclear spin I, unit: h/2π.
8 - Nuclear magnetic moment μmag.
9 - Source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.
10 - Decay: Half-live of the Selenium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
11 - Decay: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
12 - Decay percentage in percent (%).
13 - Decay energy; Particle energy related to decay type.
14 - AE = Excitation energy for metastable nuclei.
15 - Other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

 

NMR active Selenium nuclides

Nuclide
quantity 1)
spin
Nuclear magnetic
moment
μ/μN
Gyromagnetic
ratio
107 rad T-1 s-1
Quadrupole
moment
Q fm-2
Resonant
frequency
v0 bei 1 T
Relative
sensitivity
H0 = const.
v0 = const. 2)
77Se
7,60(7) %
1/2-
+0,53356(5)5,121476,08,15680,00703
0,1916

1) Quantity Percentage of natural occurrence.

2) Related to 1H = 1,000.

 

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Selenium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Se-70106 Bq10 Bq/g41.1 min
Se-73106 Bq10 Bq/g7.2 h
Se-73m106 Bq100 Bq/g39.8 min
Se-75106 Bq1 Bq/g0,2 TBq10 Bq cm-2119.6 d
Se-79107 Bq0,1 Bq/g20 TBq380000 a
Se-81106 Bq1000 Bq/g18.4 min
Se-81m+107 Bq1000 Bq/g57.3 min
Se-83105 Bq10 Bq/g22.3 min

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

 

Literature Sources and References

Properties of the Selenium nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Selenium: NMR properties - 77Se-NMR

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

[9] - B. Srinivasan, E. C. Alexander, R. D. Beaty, D. E. Sinclair, O. K. Manuel:
Double Beta Decay of Selenium-82.
In: Economic Geology, (1973), DOI 10.2113/​gsecongeo.68.2.252.

[10] - B. Srinivasan, E. C. Alexander, R. D. Beaty, D. E. Sinclair, O. K. Manuel:
Preparation of radiochemically pure 79Se and highly precise determination of its half-life.
In: Applied Radiation and Isotopes, (2010), DOI 10.1016/j.apradiso.2010.05.006.

[11] - Nagmeddin Elwaer und Holger Hintelmann:
Precise selenium isotope ratios measurement using a multimode sample introduction system (MSIS) coupled with multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS).
In: Journal of Analytical Atomic Spectrometry, (2008), DOI 10.1039/B808645C.

[12] - Kathrin Schilling:
Stable isotope fractionation of selenium by biomethylation in soil.
In: Dissertation, Universität Mainz, (2010), DOI https://nbn-resolving.de/urn:nbn:de:hebis:77-28048.

[13] - J.L. Gross, J. Claes, J. Kathawa, M. Thoennessen:
Discovery of zinc, selenium, bromine, and neodymium isotopes.
In: Atomic Data and Nuclear Data Tables, (2012), DOI 10.1016/j.adt.2011.12.001.

 


Category: Isotopes

Last update: 05.07.2020



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