View source for Physics:Isotopes of selenium

{{Short description|Nuclides with atomic number of 34 but with different mass numbers}}
{{infobox selenium isotopes}}
[[Chemistry:Selenium|Selenium]] (<sub>34</sub>Se) has six natural [[Physics:Isotope|isotope]]s that occur in significant quantities, along with the trace isotope [[Physics:Selenium-79|<sup>79</sup>Se]], which occurs in minute quantities in [[Chemistry:Uranium|uranium]] ores. Five of these isotopes are [[Physics:Stable isotope|stable]]: <sup>74</sup>Se, <sup>76</sup>Se, <sup>77</sup>Se, <sup>78</sup>Se, and <sup>80</sup>Se. The last three also occur as fission products, along with [[Physics:Selenium-79|<sup>79</sup>Se]], which has a [[Physics:Half-life|half-life]] of 327,000 years,<ref name="life">[http://www.ptb.de/en/org/6/nachrichten6/2010/60710_en.htm The half-life of <sup>79</sup>Se] {{webarchive |url=https://web.archive.org/web/20110927042432/http://www.ptb.de/en/org/6/nachrichten6/2010/60710_en.htm |date=September 27, 2011 }}</ref><ref>{{cite journal |last1=Jorg |first1=Gerhard |last2=Buhnemann |first2=Rolf |last3=Hollas |first3=Simon |last4=Kivel |first4=Niko |last5=Kossert |first5=Karsten |last6=Van Winckel |first6=Stefaan |last7=Gostomski |first7=Christoph Lierse v. |title=Preparation of radiochemically pure <sup>79</sup>Se and highly precise determination of its half-life |journal=Applied Radiation and Isotopes |volume=68 |pages=2339–51|year=2010 |doi=10.1016/j.apradiso.2010.05.006 |pmid=20627600 |issue=12}}</ref> and <sup>82</sup>Se, which has a very long half-life (~10<sup>20</sup> years, decaying via [[Physics:Double beta decay|double beta decay]] to [[Chemistry:Krypton|<sup>82</sup>Kr]]) and for practical purposes can be considered to be stable. There are 23 other unstable isotopes that have been characterized, the longest-lived being <sup>79</sup>Se with a half-life 327,000 years, <sup>75</sup>Se with a half-life of 120 days, and <sup>72</sup>Se with a half-life of 8.40 days. Of the other isotopes, <sup>73</sup>Se has the longest half-life, 7.15 hours; most others have half-lives not exceeding 38 seconds.

== List of isotopes ==
{{Isotopes table
|symbol=Se
|refs=<!-- not NUBASE2016 yet (2019-07-14) -->
|notes=m, unc(), mass#, hl#, hl-nst, spin(), spin#, daughter-st, EC, IT, n, p
}}
|-
| rowspan=2|<sup>65</sup>Se
| rowspan=2 style="text-align:right" | 34
| rowspan=2 style="text-align:right" | 31
| rowspan=2|64.96466(64)#
| rowspan=2|<50&nbsp;ms
| [[Physics:Beta decay|β<sup>+</sup>]] (>99.9%)
| <sup>65</sup>As
| rowspan=2|3/2−#
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>, p (<.1%)
| <sup>64</sup>Ge
|-
| <sup>66</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 32
| 65.95521(32)#
| 33(12)&nbsp;ms
| β<sup>+</sup>
| <sup>66</sup>As
| 0+
|
|
|-
| rowspan=2|<sup>67</sup>Se
| rowspan=2 style="text-align:right" | 34
| rowspan=2 style="text-align:right" | 33
| rowspan=2|66.95009(21)#
| rowspan=2|133(11)&nbsp;ms
| β<sup>+</sup> (99.5%)
| <sup>67</sup>As
| rowspan=2|5/2−#
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>, p (.5%)
| <sup>66</sup>Ge
|-
| <sup>68</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 34
| 67.94180(4)
| 35.5(7)&nbsp;s
| β<sup>+</sup>
| <sup>68</sup>As
| 0+
|
|
|-
| rowspan=2|<sup>69</sup>Se
| rowspan=2 style="text-align:right" | 34
| rowspan=2 style="text-align:right" | 35
| rowspan=2|68.93956(4)
| rowspan=2|27.4(2)&nbsp;s
| β<sup>+</sup> (99.955%)
| <sup>69</sup>As
| rowspan=2|(1/2−)
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>, p (.045%)
| <sup>68</sup>Ge
|-
| style="text-indent:1em" | <sup>69m1</sup>Se
| colspan="3" style="text-indent:2em" | 39.4(1)&nbsp;keV
| 2.0(2)&nbsp;μs
|
|
| 5/2−
|
|
|-
| style="text-indent:1em" | <sup>69m2</sup>Se
| colspan="3" style="text-indent:2em" | 573.9(10)&nbsp;keV
| 955(16)&nbsp;ns
|
|
| 9/2+
|
|
|-
| <sup>70</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 36
| 69.93339(7)
| 41.1(3)&nbsp;min
| β<sup>+</sup>
| <sup>70</sup>As
| 0+
|
|
|-
| <sup>71</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 37
| 70.93224(3)
| 4.74(5)&nbsp;min
| β<sup>+</sup>
| <sup>71</sup>As
| 5/2−
|
|
|-
| style="text-indent:1em" | <sup>71m1</sup>Se
| colspan="3" style="text-indent:2em" | 48.79(5)&nbsp;keV
| 5.6(7)&nbsp;μs
|
|
| 1/2− to 9/2−
|
|
|-
| style="text-indent:1em" | <sup>71m2</sup>Se
| colspan="3" style="text-indent:2em" | 260.48(10)&nbsp;keV
| 19.0(5)&nbsp;μs
|
|
| (9/2)+
|
|
|-
| <sup>72</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 38
| 71.927112(13)
| 8.40(8)&nbsp;d
| [[Physics:Electron capture|EC]]
| <sup>72</sup>As
| 0+
|
|
|-
| <sup>73</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 39
| 72.926765(11)
| 7.15(8)&nbsp;h
| β<sup>+</sup>
| <sup>73</sup>As
| 9/2+
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>73m</sup>Se
| rowspan=2 colspan="3" style="text-indent:2em" | 25.71(4)&nbsp;keV
| rowspan=2|39.8(13)&nbsp;min
| IT
| <sup>73</sup>Se
| rowspan=2|3/2−
| rowspan=2|
| rowspan=2|
|-
| β<sup>+</sup>
| <sup>73</sup>As
|-
| <sup>74</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 40
| 73.9224764(18)
| colspan=3 align=center|'''[[Physics:Observationally Stable|Observationally Stable]]'''<ref group="n">Believed to decay by β<sup>+</sup>β<sup>+</sup> to '''<sup>74</sup>Ge'''</ref>
| 0+
| 0.0089(4)
|
|-
| <sup>75</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 41
| 74.9225234(18)
| 119.779(4)&nbsp;d
| EC
| '''<sup>75</sup>As'''
| 5/2+
|
|
|-
| <sup>76</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 42
| 75.9192136(18)
| colspan=3 align=center|'''Stable'''
| 0+
| 0.0937(29)
|
|-
| <sup>77</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 43
| 76.9199140(18)
| colspan=3 align=center|'''Stable'''
| 1/2−
| 0.0763(16)
|
|-
| style="text-indent:1em" | <sup>77m</sup>Se
| colspan="3" style="text-indent:2em" | 161.9223(7)&nbsp;keV
| 17.36(5)&nbsp;s
| IT
| '''<sup>77</sup>Se'''
| 7/2+
|
|
|-
| <sup>78</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 44
| 77.9173091(18)
| colspan=3 align=center|'''Stable'''
| 0+
| 0.2377(28)
|
|-
| [[Physics:Selenium-79|<sup>79</sup>Se]]<ref group="n">[[Physics:Long-lived fission product|Long-lived fission product]]</ref>
| style="text-align:right" | 34
| style="text-align:right" | 45
| 78.9184991(18)
| 3.27(8)×10<sup>5</sup>&nbsp;y
| β<sup>−</sup>
| '''<sup>79</sup>Br'''
| 7/2+
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>79m</sup>Se
| rowspan=2 colspan="3" style="text-indent:2em" | 95.77(3)&nbsp;keV
| rowspan=2|3.92(1)&nbsp;min
| IT (99.944%)
| <sup>79</sup>Se
| rowspan=2|1/2−
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup> (.056%)
| '''<sup>79</sup>Br'''
|- 
| <sup>80</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 46
| 79.9165213(21)
| colspan=3 align=center|'''Observationally Stable'''<ref group="n">Believed to decay by β<sup>−</sup>β<sup>−</sup> to '''<sup>80</sup>Kr'''</ref>
| 0+
| 0.4961(41)
|
|-
| <sup>81</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 47
| 80.9179925(22)
| 18.45(12)&nbsp;min
| β<sup>−</sup>
| '''<sup>81</sup>Br'''
| 1/2−
|
|
|-
| rowspan=2 style="text-indent:1em" | <sup>81m</sup>Se
| rowspan=2 colspan="3" style="text-indent:2em" | 102.99(6)&nbsp;keV
| rowspan=2|57.28(2)&nbsp;min
| IT (99.948%)
| <sup>81</sup>Se
| rowspan=2|7/2+
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup> (.052%)
| '''<sup>81</sup>Br'''
|-
| <sup>82</sup>Se<ref group="n">[[Chemistry:Primordial nuclide|Primordial]] [[Physics:Radionuclide|radionuclide]]</ref>
| style="text-align:right" | 34
| style="text-align:right" | 48
| 81.9166994(22)
| '''0.97(5)×10<sup>20</sup>&nbsp;y'''
| β<sup>−</sup>β<sup>−</sup>
| '''<sup>82</sup>Kr'''
| 0+
| 0.0873(22)
| 
|-
| <sup>83</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 49
| 82.919118(4)
| 22.3(3)&nbsp;min
| β<sup>−</sup>
| <sup>83</sup>Br
| 9/2+
|
|
|-
| style="text-indent:1em" | <sup>83m</sup>Se
| colspan="3" style="text-indent:2em" | 228.50(20)&nbsp;keV
| 70.1(4)&nbsp;s
| β<sup>−</sup>
| <sup>83</sup>Br
| 1/2−
|
|
|-
| <sup>84</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 50
| 83.918462(16)
| 3.1(1)&nbsp;min
| β<sup>−</sup>
| <sup>84</sup>Br
| 0+
|
|
|-
| <sup>85</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 51
| 84.92225(3)
| 31.7(9)&nbsp;s
| β<sup>−</sup>
| <sup>85</sup>Br
| (5/2+)#
|
|
|-
| <sup>86</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 52
| 85.924272(17)
| 15.3(9)&nbsp;s
| β<sup>−</sup>
| <sup>86</sup>Br
| 0+
|
|
|-
| rowspan=2|<sup>87</sup>Se
| rowspan=2 style="text-align:right" | 34
| rowspan=2 style="text-align:right" | 53
| rowspan=2|86.92852(4)
| rowspan=2|5.50(12)&nbsp;s
| β<sup>−</sup> (99.64%)
| <sup>87</sup>Br
| rowspan=2|(5/2+)#
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>, [[Physics:Neutron emission|n]] (.36%)
| <sup>86</sup>Br
|-
| rowspan=2|<sup>88</sup>Se
| rowspan=2 style="text-align:right" | 34
| rowspan=2 style="text-align:right" | 54
| rowspan=2|87.93142(5)
| rowspan=2|1.53(6)&nbsp;s
| β<sup>−</sup> (99.01%)
| <sup>88</sup>Br
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>, n (.99%)
| <sup>87</sup>Br
|-
| rowspan=2|<sup>89</sup>Se
| rowspan=2 style="text-align:right" | 34
| rowspan=2 style="text-align:right" | 55
| rowspan=2|88.93645(32)#
| rowspan=2|0.41(4)&nbsp;s
| β<sup>−</sup> (92.2%)
| <sup>89</sup>Br
| rowspan=2|(5/2+)#
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>, n (7.8%)
| <sup>88</sup>Br
|-
| rowspan=2|<sup>90</sup>Se
| rowspan=2 style="text-align:right" | 34
| rowspan=2 style="text-align:right" | 56
| rowspan=2|89.93996(43)#
| rowspan=2|300#&nbsp;ms [>300&nbsp;ns]
| β<sup>−</sup>, n
| <sup>89</sup>Br
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>
| <sup>90</sup>Br
|-
| rowspan=2|<sup>91</sup>Se
| rowspan=2 style="text-align:right" | 34
| rowspan=2 style="text-align:right" | 57
| rowspan=2|90.94596(54)#
| rowspan=2|270(50)&nbsp;ms
| β<sup>−</sup> (79%)
| <sup>91</sup>Br
| rowspan=2|1/2+#
| rowspan=2|
| rowspan=2|
|-
| β<sup>−</sup>, n
| <sup>90</sup>Br
|-
| <sup>92</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 58
| 91.94992(64)#
| 100#&nbsp;ms [>300&nbsp;ns]
| β<sup>−</sup>
| <sup>92</sup>Br
| 0+
|
|
|-
| <sup>93</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 59
| 92.95629(86)#
| 50#&nbsp;ms [>300&nbsp;ns]
|
|
| 1/2+#
|
|
|-
| <sup>94</sup>Se
| style="text-align:right" | 34
| style="text-align:right" | 60
| 93.96049(86)#
| 20#&nbsp;ms [>300&nbsp;ns]
|
|
| 0+
|
|
{{Isotopes table/footer}}

==Use of radioisotopes==
The isotope selenium-75 has [[Medicine:Radiopharmaceutical|radiopharmaceutical]] uses. For example, it is used in high-dose-rate endorectal [[Medicine:Brachytherapy|brachytherapy]], as an alternative to [[Physics:Iridium-192|iridium-192]].<ref>{{cite journal | title = Dosimetric Considerations for Ytterbium-169, Selenium-75, and Iridium-192 Radioisotopes in High-Dose-Rate Endorectal Brachytherapy | author1 = Shoemaker T | author2 = Vuong T | author3 = Glickman H | author4 = Kaifi S | author5 = Famulari G | author6 =Enger SA | journal = Int J Radiat Oncol Biol Phys | year = 2019 | volume = 105 | issue = 4 | pages = 875–883 | doi = 10.1016/j.ijrobp.2019.07.003 | pmid = 31330175 | s2cid = 198170324 }}</ref>

In paleobiogeochemistry, the ratio in amount of selenium-82 to selenium-76 (i.e, the value of δ<sup>82/76</sup>Se) can be used to track down the [[Chemistry:Redox|redox]] conditions on Earth during the Neoproterozoic era in order to gain a deeper understanding of the [[Earth:Great Oxidation Event|rapid oxygenation]] that trigger the emergence of complex organisms.<ref>{{Cite journal |last1=Pogge von Strandmann |first1=Philip A. E. |last2=Stüeken |first2=Eva E. |last3=Elliott |first3=Tim |last4=Poulton |first4=Simon W. |last5=Dehler |first5=Carol M. |last6=Canfield |first6=Don E. |last7=Catling |first7=David C. |date=2015-12-18 |title=Selenium isotope evidence for progressive oxidation of the Neoproterozoic biosphere |url=https://www.nature.com/articles/ncomms10157 |journal=Nature Communications |language=en |volume=6 |issue=1 |pages=10157 |doi=10.1038/ncomms10157 |pmid=26679529 |pmc=4703861 |issn=2041-1723|doi-access=free }}</ref><ref>{{Cite web |last=Stüeken |first=Eva E. |title=Selenium isotopes as a biogeochemical proxy in deep time |url=https://core.ac.uk/download/pdf/161931618.pdf |website=core.ac.uk}}</ref>

== References ==
{{reflist}}

* Isotope masses from:
**{{NUBASE 2003}}
* Isotopic compositions and standard atomic masses from:
**{{CIAAW 2005}}
* Half-life, spin, and isomer data selected from the following sources.
**{{NUBASE 2003}}
**{{NNDC}}
**{{CRC85|chapter=11}}

{{Navbox element isotopes}}

[[Category:Isotopes of selenium| ]]
[[Category:Selenium]]
[[Category:Lists of isotopes by element|Selenium]]

{{Sourceattribution|Isotopes of selenium}}