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[4] (130 billion times the age of the universe).
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Standard atomic weight Ar°(Ge) | ||||||||||||||||||||||||||||||||||||||||||||||
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Stable 74Ge is the most common isotope, having a natural abundance of approximately 36%. 76Ge is the least common with a natural abundance of approximately 7%.[5]
At least 27 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 270.95 d. It decays to the medically useful positron-emitting isotope 68Ga. (See gallium-68 generator for notes on the source of this isotope, and its medical use.) The least stable known germanium isotope is 59Ge with a half-life of 13.3 ms.
While most of germanium's radioisotopes decay by beta decay, 61Ge and 65Ge can also decay by β+-delayed proton emission.[5] 84Ge through 87Ge also have minor β−-delayed neutron emission decay paths.[5]
76Ge is used in experiments on the nature of neutrinos, by searching for neutrinoless double beta decay.
List of isotopes
edit
Nuclide [n 1] |
Z | N | Isotopic mass (Da)[6] [n 2][n 3] |
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)# | 13.3(17) ms | β+, p (93%) | 58Zn | 7/2−# | ||||||||||||
β+ (7%) | 59Ga | ||||||||||||||||||
2p (<0.2%) | 57Zn | ||||||||||||||||||
60Ge | 32 | 28 | 59.97045(32)# | 21(6) ms | β+, p | 59Zn | 0+ | ||||||||||||
β+, 2p (<14%) | 58Cu | ||||||||||||||||||
61Ge | 32 | 29 | 60.96373(32)# | 40.7(4) ms | β+, p (87%) | 60Zn | 3/2−# | ||||||||||||
β+ (18%) | 61Ga | ||||||||||||||||||
62Ge | 32 | 30 | 61.95476(15)# | 82.5(14) ms | β+ | 62Ga | 0+ | ||||||||||||
63Ge | 32 | 31 | 62.949628(40) | 153.6(11) ms | β+ | 63Ga | 3/2−# | ||||||||||||
64Ge | 32 | 32 | 63.9416899(40) | 63.7(25) s | β+ | 64Ga | 0+ | ||||||||||||
65Ge | 32 | 33 | 64.9393681(23) | 30.9(5) s | β+ (99.99%) | 65Ga | 3/2− | ||||||||||||
β+, p (0.011%) | 64Zn | ||||||||||||||||||
66Ge | 32 | 34 | 65.9338621(26) | 2.26(5) h | β+ | 66Ga | 0+ | ||||||||||||
67Ge | 32 | 35 | 66.9327170(46) | 18.9(3) min | β+ | 67Ga | 1/2− | ||||||||||||
67m1Ge | 18.20(5) keV | 13.7(9) μs | IT | 67Ge | 5/2− | ||||||||||||||
67m2Ge | 751.70(6) keV | 109.1(38) ns | IT | 67Ge | 9/2+ | ||||||||||||||
68Ge[n 9] | 32 | 36 | 67.9280953(20) | 271.05(8) d | EC | 68Ga | 0+ | ||||||||||||
69Ge | 32 | 37 | 68.9279645(14) | 39.05(10) h | β+ | 69Ga | 5/2− | ||||||||||||
69m1Ge | 86.76(2) keV | 5.1(2) μs | IT | 69Ge | 1/2− | ||||||||||||||
69m2Ge | 397.94(2) keV | 2.81(5) μs | IT | 69Ge | 9/2+ | ||||||||||||||
70Ge | 32 | 38 | 69.92424854(88) | Stable | 0+ | 0.2052(19) | |||||||||||||
71Ge | 32 | 39 | 70.92495212(87) | 11.468(8) d[7] | EC | 71Ga | 1/2− | ||||||||||||
71mGe | 198.354(14) keV | 20.41(18) ms | IT | 71Ge | 9/2+ | ||||||||||||||
72Ge | 32 | 40 | 71.922075824(81) | Stable | 0+ | 0.2745(15) | |||||||||||||
72mGe | 691.43(4) keV | 444.2(8) ns | IT | 72Ge | 0+ | ||||||||||||||
73Ge | 32 | 41 | 72.923458954(61) | Stable | 9/2+ | 0.0776(8) | |||||||||||||
73m1Ge | 13.2845(15) keV | 2.91(3) μs | IT | 73Ge | 5/2+ | ||||||||||||||
73m2Ge | 66.725(9) keV | 499(11) ms | IT | 73Ge | 1/2− | ||||||||||||||
74Ge | 32 | 42 | 73.921177760(13) | Stable | 0+ | 0.3652(12) | |||||||||||||
75Ge | 32 | 43 | 74.922858370(55) | 82.78(4) min | β− | 75As | 1/2− | ||||||||||||
75m1Ge | 139.69(3) keV | 47.7(5) s | IT (99.97%) | 75Ge | 7/2+ | ||||||||||||||
β− (0.030%) | 75As | ||||||||||||||||||
75m2Ge | 192.19(6) keV | 216(5) ns | IT | 75Ge | 5/2+ | ||||||||||||||
76Ge[n 10] | 32 | 44 | 75.921402725(19) | (2.022±0.018±0.038)×1021 y[8] | β−β− | 76Se | 0+ | 0.0775(12) | |||||||||||
77Ge | 32 | 45 | 76.923549843(56) | 11.211(3) h | β− | 77As | 7/2+ | ||||||||||||
77mGe | 159.71(6) keV | 53.7(6) s | β− (81%) | 77As | 1/2− | ||||||||||||||
IT (19%) | 77Ge | ||||||||||||||||||
78Ge | 32 | 46 | 77.9228529(38) | 88.0(10) min | β− | 78As | 0+ | ||||||||||||
79Ge | 32 | 47 | 78.925360(40) | 18.98(3) s | β− | 79As | (1/2)− | ||||||||||||
79mGe | 185.95(4) keV | 39.0(10) s | β− (96%) | 79As | 7/2+# | ||||||||||||||
IT (4%) | 79Ge | ||||||||||||||||||
80Ge | 32 | 48 | 79.9253508(22) | 29.5(4) s | β− | 80As | 0+ | ||||||||||||
81Ge | 32 | 49 | 80.9288329(22) | 9(2) s | β− | 81As | 9/2+# | ||||||||||||
81mGe | 679.14(4) keV | 6(2) s | β− | 81As | (1/2+) | ||||||||||||||
IT (<1%) | 81Ge | ||||||||||||||||||
82Ge | 32 | 50 | 81.9297740(24) | 4.31(19) s | β− | 82As | 0+ | ||||||||||||
83Ge | 32 | 51 | 82.9345391(26) | 1.85(6) s | β− | 83As | (5/2+) | ||||||||||||
84Ge | 32 | 52 | 83.9375751(34) | 951(9) ms | β− (89.4%) | 84As | 0+ | ||||||||||||
β−, n (10.6%) | 83As | ||||||||||||||||||
85Ge | 32 | 53 | 84.9429697(40) | 495(5) ms | β− (82.8%) | 85As | (3/2+,5/2+)# | ||||||||||||
β−, n (17.2%) | 84As | ||||||||||||||||||
86Ge | 32 | 54 | 85.94697(47) | 221.6(11) ms | β− (55%) | 86As | 0+ | ||||||||||||
β−, n (45%) | 85As | ||||||||||||||||||
87Ge | 32 | 55 | 86.95320(32)# | 103(4) ms | β− | 87As | 5/2+# | ||||||||||||
88Ge | 32 | 56 | 87.95757(43)# | 61(6) ms | β− | 88As | 0+ | ||||||||||||
89Ge | 32 | 57 | 88.96453(43)# | 60# ms [>300 ns] | 3/2+# | ||||||||||||||
90Ge | 32 | 58 | 89.96944(54)# | 30# ms [>400 ns] | 0+ | ||||||||||||||
91Ge[9] | 32 | 59 | |||||||||||||||||
92Ge[9] | 32 | 60 | |||||||||||||||||
This table header & footer: |
- ^ mGe – Excited nuclear isomer.
- ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
- ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
- ^ Bold half-life – nearly stable, half-life longer than age of universe.
- ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^
Modes of decay:
EC: Electron capture IT: Isomeric transition n: Neutron emission p: Proton emission - ^ Bold symbol as daughter – Daughter product is stable.
- ^ ( ) spin value – Indicates spin with weak assignment arguments.
- ^ Used to generate 68Ga
- ^ Primordial radionuclide
References
edit- ^ a b c d e 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.
- ^ "Standard Atomic Weights: Germanium". CIAAW. 2009.
- ^ 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.
- ^ A. M. Bakalyarov; A. Ya. Balysh; S. T. Belyaev; V. I. Lebedev; S. V. Zhukov (2003). "Results of the experiment on investigation of Germanium-76 double beta decay". Physics of Particles and Nuclei Letters. 2 (2): 77–81. arXiv:hep-ex/0309016. Bibcode:2003hep.ex....9016B.
- ^ a b c Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- ^ 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.
- ^ 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.
- ^ 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). American Physical Society (APS): 142501. arXiv:2308.09795. Bibcode:2023PhRvL.131n2501A. doi:10.1103/physrevlett.131.142501. ISSN 0031-9007. PMID 37862664. S2CID 261049638.
- ^ a b 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). doi:10.1103/PhysRevC.109.044313.