Isotopes of germanium

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 (130 billion times the age of the universe).

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%.

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. 84Ge through 87Ge also have minor β−-delayed neutron emission decay paths.

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

List of isotopes

 * rowspan=3|59Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 27
 * rowspan=3|58.98243(43)#
 * rowspan=3|13.3(17) ms
 * β+, p (93%)
 * 58Zn
 * rowspan=3|7/2−#
 * rowspan=3|
 * rowspan=3|
 * β+ (7%)
 * 59Ga
 * 2p?
 * 57Zn
 * rowspan=2|60Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 28
 * rowspan=2|59.97045(32)#
 * rowspan=2|21(6) ms
 * β+, p
 * 59Zn
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β+, 2p? (<14%)
 * 58Cu
 * rowspan=2|61Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 29
 * rowspan=2|60.96373(32)#
 * rowspan=2|40.7(4) ms
 * β+, p (87%)
 * 60Zn
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β+ (18%)
 * 61Ga
 * rowspan=2|62Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 30
 * rowspan=2|61.95476(15)#
 * rowspan=2|82.5(14) ms
 * β+
 * 62Ga
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β+, p?
 * 61Zn
 * rowspan=2|63Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 31
 * rowspan=2|62.949628(40)
 * rowspan=2|153.6(11) ms
 * β+
 * 63Ga
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β+, p?
 * 62Zn
 * 64Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 32
 * 63.9416899(40)
 * 63.7(25) s
 * β+
 * 64Ga
 * 0+
 * rowspan=2|65Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 33
 * rowspan=2|64.9393681(23)
 * rowspan=2|30.9(5) s
 * β+ (99.99%)
 * 65Ga
 * rowspan=2|3/2−
 * rowspan=2|
 * rowspan=2|
 * β+, p (0.011%)
 * 64Zn
 * 66Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 34
 * 65.9338621(26)
 * 2.26(5) h
 * β+
 * 66Ga
 * 0+
 * 67Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 35
 * 66.9327170(46)
 * 18.9(3) min
 * β+
 * 67Ga
 * 1/2−
 * style="text-indent:1em" | 67m1Ge
 * colspan="3" style="text-indent:2em" | 18.20(5) keV
 * 13.7(9) μs
 * IT
 * 67Ge
 * 5/2−
 * style="text-indent:1em" | 67m2Ge
 * colspan="3" style="text-indent:2em" | 751.70(6) keV
 * 109.1(38) ns
 * IT
 * 67Ge
 * 9/2+
 * 68Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 36
 * 67.9280953(20)
 * 271.05(8) d
 * EC
 * 68Ga
 * 0+
 * 69Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 37
 * 68.9279645(14)
 * 39.05(10) h
 * β+
 * 69Ga
 * 5/2−
 * style="text-indent:1em" | 69m1Ge
 * colspan="3" style="text-indent:2em" | 86.76(2) keV
 * 5.1(2) μs
 * IT
 * 69Ge
 * 1/2−
 * style="text-indent:1em" | 69m2Ge
 * colspan="3" style="text-indent:2em" | 397.94(2) keV
 * 2.81(5) μs
 * IT
 * 69Ge
 * 9/2+
 * 70Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 38
 * 69.92424854(88)
 * colspan=3 align=center|Stable
 * 0+
 * 0.2052(19)
 * 71Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 39
 * 70.92495212(87)
 * 11.468(8) d
 * EC
 * 71Ga
 * 1/2−
 * style="text-indent:1em" | 71mGe
 * colspan="3" style="text-indent:2em" | 198.354(14) keV
 * 20.41(18) ms
 * IT
 * 71Ge
 * 9/2+
 * 72Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 40
 * 71.922075824(81)
 * colspan=3 align=center|Stable
 * 0+
 * 0.2745(15)
 * style="text-indent:1em" | 72mGe
 * colspan="3" style="text-indent:2em" | 691.43(4) keV
 * 444.2(8) ns
 * IT
 * 72Ge
 * 0+
 * 73Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 41
 * 72.923458954(61)
 * colspan=3 align=center|Stable
 * 9/2+
 * 0.0776(8)
 * style="text-indent:1em" | 73m1Ge
 * colspan="3" style="text-indent:2em" | 13.2845(15) keV
 * 2.91(3) μs
 * IT
 * 73Ge
 * 5/2+
 * style="text-indent:1em" | 73m2Ge
 * colspan="3" style="text-indent:2em" | 66.725(9) keV
 * 499(11) ms
 * IT
 * 73Ge
 * 1/2−
 * 74Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 42
 * 73.921177760(13)
 * colspan=3 align=center|Stable
 * 0+
 * 0.3652(12)
 * 75Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 43
 * 74.922858370(55)
 * 82.78(4) min
 * β−
 * 75As
 * 1/2−
 * rowspan=2 style="text-indent:1em" | 75m1Ge
 * rowspan=2 colspan="3" style="text-indent:2em" | 139.69(3) keV
 * rowspan=2|47.7(5) s
 * IT (99.97%)
 * 75Ge
 * rowspan=2|7/2+
 * rowspan=2|
 * rowspan=2|
 * β− (0.030%)
 * 75As
 * style="text-indent:1em" | 75m2Ge
 * colspan="3" style="text-indent:2em" | 192.19(6) keV
 * 216(5) ns
 * IT
 * 75Ge
 * 5/2+
 * 76Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 44
 * 75 921402.725(19)
 * (2.022±0.018±0.038) y
 * β−β−
 * 76Se
 * 0+
 * 0.0775(12)
 * 77Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 45
 * 76 923549.843(56)
 * 11.211(3) h
 * β−
 * 77As
 * 7/2+
 * rowspan=2 style="text-indent:1em" | 77mGe
 * rowspan=2 colspan="3" style="text-indent:2em" | 159.71(6) keV
 * rowspan=2|53.7(6) s
 * β− (81%)
 * 77As
 * rowspan=2|1/2−
 * rowspan=2|
 * rowspan=2|
 * IT (19%)
 * 77Ge
 * 78Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 46
 * 77.9228529(38)
 * 88.0(10) min
 * β−
 * 78As
 * 0+
 * 79Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 47
 * 78.925360(40)
 * 18.98(3) s
 * β−
 * 79As
 * (1/2)−
 * rowspan=2 style="text-indent:1em" | 79mGe
 * rowspan=2 colspan="3" style="text-indent:2em" | 185.95(4) keV
 * rowspan=2|39.0(10) s
 * β− (96%)
 * 79As
 * rowspan=2|7/2+#
 * rowspan=2|
 * rowspan=2|
 * IT (4%)
 * 79Ge
 * 80Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 48
 * 79.9253508(22)
 * 29.5(4) s
 * β−
 * 80As
 * 0+
 * 81Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 49
 * 80.9288329(22)
 * 9(2) s
 * β−
 * 81As
 * 9/2+#
 * rowspan=2 style="text-indent:1em" | 81mGe
 * rowspan=2 colspan="3" style="text-indent:2em" | 679.14(4) keV
 * rowspan=2|6(2) s
 * β−
 * 81As
 * rowspan=2|(1/2+)
 * rowspan=2|
 * rowspan=2|
 * IT? (<1%)
 * 81Ge
 * 82Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 50
 * 81.9297740(24)
 * 4.31(19) s
 * β−
 * 82As
 * 0+
 * rowspan=2|83Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 51
 * rowspan=2|82.9345391(26)
 * rowspan=2|1.85(6) s
 * β−
 * 83As
 * rowspan=2|(5/2+)
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 82As
 * rowspan=2|84Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 52
 * rowspan=2|83.9375751(34)
 * rowspan=2|951(9) ms
 * β− (89.4%)
 * 84As
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (10.6%)
 * 83As
 * rowspan=3|85Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 53
 * rowspan=3|84.9429697(40)
 * rowspan=3|495(5) ms
 * β− (82.8%)
 * 85As
 * rowspan=3|(3/2+,5/2+)#
 * rowspan=3|
 * rowspan=3|
 * β−, n (17.2%)
 * 84As
 * β−, 2n?
 * 83As
 * rowspan=2|86Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2|85.94697(47)
 * rowspan=2|221.6(11) ms
 * β− (55%)
 * 86As
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (45%)
 * 85As
 * rowspan=3|87Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 55
 * rowspan=3|86.95320(32)#
 * rowspan=3|103(4) ms
 * β−
 * 87As
 * rowspan=3|5/2+#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 86As
 * β−, 2n?
 * 85As
 * rowspan=3|88Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3|87.95757(43)#
 * rowspan=3|61(6) ms
 * β−
 * 88As
 * rowspan=3|0+
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 87As
 * β−, 2n?
 * 86As
 * rowspan=3|89Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 57
 * rowspan=3|88.96453(43)#
 * rowspan=3|60# ms [>300 ns]
 * β−?
 * 89As
 * rowspan=3|3/2+#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 88As
 * β−, 2n?
 * 87As
 * rowspan=3|90Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 57
 * rowspan=3|89.96944(54)#
 * rowspan=3|30# ms [>400 ns]
 * β−?
 * 90As
 * rowspan=3|0+
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 89As
 * β−, 2n?
 * 88As
 * 91Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 59
 * 92Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 60
 * rowspan=2|84Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 52
 * rowspan=2|83.9375751(34)
 * rowspan=2|951(9) ms
 * β− (89.4%)
 * 84As
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (10.6%)
 * 83As
 * rowspan=3|85Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 53
 * rowspan=3|84.9429697(40)
 * rowspan=3|495(5) ms
 * β− (82.8%)
 * 85As
 * rowspan=3|(3/2+,5/2+)#
 * rowspan=3|
 * rowspan=3|
 * β−, n (17.2%)
 * 84As
 * β−, 2n?
 * 83As
 * rowspan=2|86Ge
 * rowspan=2 style="text-align:right" | 32
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2|85.94697(47)
 * rowspan=2|221.6(11) ms
 * β− (55%)
 * 86As
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (45%)
 * 85As
 * rowspan=3|87Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 55
 * rowspan=3|86.95320(32)#
 * rowspan=3|103(4) ms
 * β−
 * 87As
 * rowspan=3|5/2+#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 86As
 * β−, 2n?
 * 85As
 * rowspan=3|88Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3|87.95757(43)#
 * rowspan=3|61(6) ms
 * β−
 * 88As
 * rowspan=3|0+
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 87As
 * β−, 2n?
 * 86As
 * rowspan=3|89Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 57
 * rowspan=3|88.96453(43)#
 * rowspan=3|60# ms [>300 ns]
 * β−?
 * 89As
 * rowspan=3|3/2+#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 88As
 * β−, 2n?
 * 87As
 * rowspan=3|90Ge
 * rowspan=3 style="text-align:right" | 32
 * rowspan=3 style="text-align:right" | 57
 * rowspan=3|89.96944(54)#
 * rowspan=3|30# ms [>400 ns]
 * β−?
 * 90As
 * rowspan=3|0+
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 89As
 * β−, 2n?
 * 88As
 * 91Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 59
 * 92Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 60
 * rowspan=3|30# ms [>400 ns]
 * β−?
 * 90As
 * rowspan=3|0+
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 89As
 * β−, 2n?
 * 88As
 * 91Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 59
 * 92Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 60
 * 92Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 60
 * 92Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 60
 * 92Ge
 * style="text-align:right" | 32
 * style="text-align:right" | 60
 * style="text-align:right" | 32
 * style="text-align:right" | 60