Germanium (32Ge) has five naturally occurring isotopes, 70Ge, 72Ge, 73Ge, 74Ge, and 76Ge. Of these, 76Ge is very slightly radioactive, undergoing double beta decay with a half-life of 2.02 × 1021 years[3] (over 100 billion times the age of the universe).

Stable 74Ge is the most common isotope, having a natural abundance of 36.52%; 76Ge is the least common with a natural abundance of 7.75%.

At least 27 additional radioisotopes have also been synthesized ranging in atomic mass from 58 to 89. The most stable of these is 68Ge, decaying by electron capture with a half-life of 271.05 days, whose daughter is the medically useful positron-emitting isotope 68Ga. (See gallium-68 generator for notes on the source of this isotope, and its medical use.) The next after that is 71Ge, also decaying by electron capture with half-life 11.468 days,[2] and the rest are all less than two days, most under two hours.

While most of germanium's radioisotopes decay by beta decay - β+ for isotopes lighter than 74-76, and β- for those heavier - isotopes as heavy as 65Ge can also decay by β+-delayed proton emission, and those as light as 84Ge by β−-delayed neutron emission.

76Ge is used in experiments on the nature of neutrinos, by searching for neutrinoless double beta decay.

List of isotopes

Nuclide
[n 1]		 Z N Isotopic mass (Da)[6]
[n 2][n 3]		 Discovery
year[7][8]		 Half-life[1]
[n 4][n 5]		 Decay
mode[1]
[n 6]		 Daughter
isotope
[n 7]		 Spin and
parity[1]
[n 8][n 5]		 Natural abundance (mole fraction)
Excitation energy Normal proportion[1] Range of variation
59Ge 32 27 58.98243(43)# 2015 13.3(17) ms β+, p 58Zn 7/2−#
2p (<0.2%) 57Zn
60Ge 32 28 59.970286(24)[9] 2005 25.0(3) ms[9] β+, p (67%[9]) 59Zn 0+
β+ (33%[9]) 60Ga
61Ge 32 29 60.96373(32)# 1987 40.7(4) ms β+, p (87%) 60Zn 3/2−#
β+ (13%) 61Ga
62Ge 32 30 61.95463(15)[9] 1991 73.5(1) ms[9] β+ 62Ga 0+
63Ge 32 31 62.949628(40) 1991 153.6(11) ms β+ 63Ga 3/2−#
64Ge 32 32 63.9416899(40) 1972 63.7(25) s β+ 64Ga 0+
65Ge 32 33 64.9393681(23) 1972 30.9(5) s β+ (99.99%) 65Ga 3/2−
β+, p (0.011%) 64Zn
66Ge 32 34 65.9338621(26) 1950 2.26(5) h β+ 66Ga 0+
67Ge 32 35 66.9327170(46) 1950 18.9(3) min β+ 67Ga 1/2−
67m1Ge 18.20(5) keV 1978 13.7(9) μs IT 67Ge 5/2−
67m2Ge 751.70(6) keV 1978 109.1(38) ns IT 67Ge 9/2+
68Ge[n 9] 32 36 67.9280953(20) 1948 271.05(8) d EC 68Ga 0+
69Ge 32 37 68.9279645(14) 1938 39.05(10) h β+ 69Ga 5/2−
69m1Ge 86.76(2) keV 1964 5.1(2) μs IT 69Ge 1/2−
69m2Ge 397.94(2) keV 1970 2.81(5) μs IT 69Ge 9/2+
70Ge 32 38 69.92424854(88) 1923 Stable 0+ 0.2052(19)
71Ge 32 39 70.92495212(87) 1941 11.468(8) d[2] EC 71Ga 1/2−
71mGe 198.354(14) keV 1961 20.41(18) ms IT 71Ge 9/2+
72Ge 32 40 71.922075824(81) 1923 Stable 0+ 0.2745(15)
72mGe 691.43(4) keV 1949 444.2(8) ns IT 72Ge 0+
73Ge 32 41 72.923458954(61) 1931 Stable 9/2+ 0.0776(8)
73m1Ge 13.2845(15) keV 1953 2.91(3) μs IT 73Ge 5/2+
73m2Ge 66.725(9) keV 1957 499(11) ms IT 73Ge 1/2−
74Ge 32 42 73.921177760(13) 1923 Stable 0+ 0.3652(12)
75Ge 32 43 74.922858370(55) 1939 82.78(4) min β− 75As 1/2−
75m1Ge 139.69(3) keV 1952 47.7(5) s IT (99.97%) 75Ge 7/2+
β− (0.030%) 75As
75m2Ge 192.19(6) keV 1982 216(5) ns IT 75Ge 5/2+
76Ge[n 10][n 11] 32 44 75.921402725(19) 1931 (2.022±0.018±0.038)×1021 y[3] β−β− 76Se 0+ 0.0775(12)
77Ge 32 45 76.923549843(56) 1939 11.211(3) h β− 77As 7/2+
77mGe 159.71(6) keV 1947 53.7(6) s β− (81%) 77As 1/2−
IT (19%) 77Ge
78Ge 32 46 77.9228529(38) 1951 88.0(10) min β− 78As 0+
79Ge 32 47 78.925360(40) 1970 18.98(3) s β− 79As (1/2)−
79mGe 185.95(4) keV 1974 39.0(10) s β− (96%) 79As 7/2+#
IT (4%) 79Ge
80Ge 32 48 79.9253508(22) 1972 29.5(4) s β− 80As 0+
81Ge 32 49 80.9288329(22) 1972 9(2) s β− 81As 9/2+#
81mGe 679.14(4) keV 1981 6(2) s β− 81As (1/2+)
IT (<1%) 81Ge
82Ge 32 50 81.9297740(24) 1972 4.31(19) s β− 82As 0+
83Ge 32 51 82.9345391(26) 1972 1.85(6) s β− 83As (5/2+)
84Ge 32 52 83.9375751(34) 1972 951(9) ms β− (89.4%) 84As 0+
β−, n (10.6%) 83As
85Ge 32 53 84.9429697(40) 1991 495(5) ms β− (82.8%) 85As (3/2+,5/2+)#
β−, n (17.2%) 84As
86Ge 32 54 85.94697(47) 1994 221.6(11) ms β− (55%) 86As 0+
β−, n (45%) 85As
87Ge 32 55 86.95320(32)# 1997 103(4) ms β− 87As 5/2+#
88Ge 32 56 87.95757(43)# 1997 61(6) ms β− 88As 0+
89Ge 32 57 88.96453(43)# 1997 60# ms [>300 ns] 3/2+#
90Ge 32 58 89.96944(54)# 2010 30# ms [>400 ns] 0+
91Ge[10] 32 59 2024
92Ge[10] 32 60 2024
This table header & footer:
  1. ↑ mGe – 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:
    EC:Electron capture
    IT:Isomeric transition
    n:Neutron emission
    p:Proton emission
  7. ↑ Bold symbol as daughter – Daughter product is stable.
  8. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  9. ↑ Used to generate 68Ga
  10. ↑ Fission product
  11. ↑ Primordial radionuclide

See also

Daughter products other than germanium

References

  1. 1 2 3 4 5 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 3 Norman, E. B.; Drobizhev, A.; Gharibyan, N.; Gregorich, K. E.; Kolomensky, Yu. G.; Sammis, B. N.; Scielzo, N. D.; Shusterman, J. A.; Thomas, K. J. (30 May 2024). "Half-life of Ge 71 and the gallium anomaly". Physical Review C. 109 (5). doi:10.1103/PhysRevC.109.055501.
  3. 1 2 3 M. Agostini; et al. (2023-10-03). "Final Results of GERDA on the Two-Neutrino Double-β Decay Half-Life of 76Ge". Physical Review Letters. 131 (14) 142501. American Physical Society (APS). arXiv:2308.09795. Bibcode:2023PhRvL.131n2501A. doi:10.1103/physrevlett.131.142501. ISSN 0031-9007. PMID 37862664. S2CID 261049638.
  4. ↑ "Standard Atomic Weights: Germanium". CIAAW. 2009.
  5. ↑ 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.
  6. ↑ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3) 030003. doi:10.1088/1674-1137/abddaf.
  7. ↑ FRIB Nuclear Data Group. "Discovery of Nuclides Project, Isotope Database". doi:10.11578/frib/2279152.
  8. ↑ FRIB Nuclear Data Group. "Discovery of Nuclides Project, Isomer Database". doi:10.11578/frib/2572219.
  9. 1 2 3 4 5 6 Orrigo, S. E. A.; Rubio, B.; Gelletly, W.; Aguilera, P.; Algora, A.; Morales, A. I.; Agramunt, J.; Ahn, D. S.; Ascher, P.; Blank, B.; Borcea, C.; Boso, A.; Cakirli, R. B.; Chiba, J.; de Angelis, G.; de France, G.; Diel, F.; Doornenbal, P.; Fujita, Y.; Fukuda, N.; Ganioğlu, E.; Gerbaux, M.; Giovinazzo, J.; Go, S.; Goigoux, T.; Grévy, S.; Guadilla, V.; Inabe, N.; Kiss, G. G.; Kubo, T.; Kubono, S.; Kurtukian-Nieto, T.; Lubos, D.; Magron, C.; Molina, F.; Montaner-Pizá, A.; Napoli, D.; Nishimura, D.; Nishimura, S.; Oikawa, H.; Phong, V. H.; Sakurai, H.; Shimizu, Y.; Sidong, C.; Söderström, P.-A.; Sumikama, T.; Suzuki, H.; Takeda, H.; Takei, Y.; Tanaka, M.; Wu, J.; Yagi, S. (29 January 2021). "β decay of the very neutron-deficient Ge 60 and Ge 62 nuclei". Physical Review C. 103 (1) 014324. arXiv:2008.10576. doi:10.1103/PhysRevC.103.014324.
  10. 1 2 Shimizu, Y.; Kubo, T.; Sumikama, T.; Fukuda, N.; Takeda, H.; Suzuki, H.; Ahn, D. S.; Inabe, N.; Kusaka, K.; Ohtake, M.; Yanagisawa, Y.; Yoshida, K.; Ichikawa, Y.; Isobe, T.; Otsu, H.; Sato, H.; Sonoda, T.; Murai, D.; Iwasa, N.; Imai, N.; Hirayama, Y.; Jeong, S. C.; Kimura, S.; Miyatake, H.; Mukai, M.; Kim, D. G.; Kim, E.; Yagi, A. (8 April 2024). "Production of new neutron-rich isotopes near the N = 60 isotones Ge 92 and As 93 by in-flight fission of a 345 MeV/nucleon U 238 beam". Physical Review C. 109 (4) 044313. doi:10.1103/PhysRevC.109.044313.
source: https://en.wikipedia.org/wiki/Isotopes_of_germanium