Isotopes of germanium

Isotopes of germanium (₃₂Ge)
Standard atomic weight Ar°(Ge)
	72.630±0.008; 72.630±0.008 (abridged);
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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).

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

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)
Nuclide ^{[n 1]}	Excitation energy			Half-life^[1] ^{[n 4]}^{[n 5]}	Decay mode^[1] ^{[n 6]}	Daughter isotope ^{[n 7]}	Spin and parity^[1] ^{[n 8]}^{[n 5]}	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?	⁵⁷Zn
⁶⁰Ge	32	28	59.97045(32)#	21(6) ms	β⁺, p	⁵⁹Zn	0+
⁶⁰Ge	32	28	59.97045(32)#	21(6) ms	β⁺, 2p? (<14%)	⁵⁸Cu	0+
⁶¹Ge	32	29	60.96373(32)#	40.7(4) ms	β⁺, p (87%)	⁶⁰Zn	3/2−#
⁶¹Ge	32	29	60.96373(32)#	40.7(4) ms	β⁺ (18%)	⁶¹Ga	3/2−#
⁶²Ge	32	30	61.95476(15)#	82.5(14) ms	β⁺	⁶²Ga	0+
⁶²Ge	32	30	61.95476(15)#	82.5(14) ms	β⁺, p?	⁶¹Zn	0+
⁶³Ge	32	31	62.949628(40)	153.6(11) ms	β⁺	⁶³Ga	3/2−#
⁶³Ge	32	31	62.949628(40)	153.6(11) ms	β⁺, p?	⁶²Zn	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−
⁶⁵Ge	32	33	64.9393681(23)	30.9(5) s	β⁺, p (0.011%)	⁶⁴Zn	3/2−
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)	11.43(3) d	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+
^75m1Ge	139.69(3) keV			47.7(5) s	β⁻ (0.030%)	⁷⁵As	7/2+
^75m2Ge	192.19(6) keV			216(5) ns	IT	⁷⁵Ge	5/2+
⁷⁶Ge^{[n 10]}	32	44	75 921402.725(19)	(2.022±0.018±0.038)×10²¹ y^[7]	β⁻β⁻	⁷⁶Se	0+	0.0775(12)
⁷⁷Ge	32	45	76 923549.843(56)	11.211(3) h	β⁻	⁷⁷As	7/2+
^77mGe	159.71(6) keV			53.7(6) s	β⁻ (81%)	⁷⁷As	1/2−
^77mGe	159.71(6) keV			53.7(6) s	IT (19%)	⁷⁷Ge	1/2−
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+#
^79mGe	185.95(4) keV			39.0(10) s	IT (4%)	⁷⁹Ge	7/2+#
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+)
^81mGe	679.14(4) keV			6(2) s	IT? (<1%)	⁸¹Ge	(1/2+)
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+)
⁸³Ge	32	51	82.9345391(26)	1.85(6) s	β⁻, n?	⁸²As	(5/2+)
⁸⁴Ge	32	52	83.9375751(34)	951(9) ms	β⁻ (89.4%)	⁸⁴As	0+
⁸⁴Ge	32	52	83.9375751(34)	951(9) ms	β⁻, n (10.6%)	⁸³As	0+
⁸⁵Ge	32	53	84.9429697(40)	495(5) ms	β⁻ (82.8%)	⁸⁵As	(3/2+,5/2+)#
					β⁻, n (17.2%)	⁸⁴As
					β⁻, 2n?	⁸³As
⁸⁶Ge	32	54	85.94697(47)	221.6(11) ms	β⁻ (55%)	⁸⁶As	0+
⁸⁶Ge	32	54	85.94697(47)	221.6(11) ms	β⁻, n (45%)	⁸⁵As	0+
⁸⁷Ge	32	55	86.95320(32)#	103(4) ms	β⁻	⁸⁷As	5/2+#
					β⁻, n?	⁸⁶As
					β⁻, 2n?	⁸⁵As
⁸⁸Ge	32	56	87.95757(43)#	61(6) ms	β⁻	⁸⁸As	0+
					β⁻, n?	⁸⁷As
					β⁻, 2n?	⁸⁶As
⁸⁹Ge	32	57	88.96453(43)#	60# ms [>300 ns]	β⁻?	⁸⁹As	3/2+#
					β⁻, n?	⁸⁸As
					β⁻, 2n?	⁸⁷As
⁹⁰Ge	32	57	89.96944(54)#	30# ms [>400 ns]	β⁻?	⁹⁰As	0+
					β⁻, n?	⁸⁹As
					β⁻, 2n?	⁸⁸As
⁹¹Ge^[8]	32	59
⁹²Ge^[8]	32	60
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References

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