Isotopes of selenium

Isotopes of selenium (₃₄Se)
γ	–
γ	–
Standard atomic weight Ar°(Se)
	78.971±0.008; 78.971±0.008 (abridged);
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Last updated October 05, 2024

Selenium (₃₄Se) has six natural isotopes that occur in significant quantities, along with the trace isotope ⁷⁹Se, which occurs in minute quantities in uranium ores. Five of these isotopes are stable: ⁷⁴Se, ⁷⁶Se, ⁷⁷Se, ⁷⁸Se, and ⁸⁰Se. The last three also occur as fission products, along with ⁷⁹Se, which has a half-life of 327,000 years,^[4]^[5] and ⁸²Se, which has a very long half-life (~10²⁰ years, decaying via double beta decay to ⁸²Kr) and for practical purposes can be considered to be stable. There are 23 other unstable isotopes that have been characterized, the longest-lived being ⁷⁹Se with a half-life 327,000 years, ⁷⁵Se with a half-life of 120 days, and ⁷²Se with a half-life of 8.40 days. Of the other isotopes, ⁷³Se has the longest half-life, 7.15 hours; most others have half-lives not exceeding 38 seconds.

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
⁶³Se	34	29	62.98191(54)#	13.2(39) ms	β⁺, p (89%)	⁶²Ge	3/2−#
					β⁺ (11%)	⁶³As
					2p? (<0.5%)	⁶¹Ge
⁶⁴Se	34	30	63.97117(54)#	22.6(2) ms	β⁺?	⁶⁴As	0+
⁶⁴Se	34	30	63.97117(54)#	22.6(2) ms	β⁺, p?	⁶³Ge	0+
⁶⁵Se	34	31	64.96455(32)#	34.2(7) ms	β⁺, p (87%)	⁶⁴Ge	3/2−#
⁶⁵Se	34	31	64.96455(32)#	34.2(7) ms	β⁺ (13%)	⁶⁵As	3/2−#
⁶⁶Se	34	32	65.95528(22)#	54(4) ms	β⁺	⁶⁶As	0+
⁶⁶Se	34	32	65.95528(22)#	54(4) ms	β⁺, p?	⁶⁵Ge	0+
⁶⁷Se	34	33	66.949994(72)	133(4) ms	β⁺ (99.5%)	⁶⁷As	5/2−#
⁶⁷Se	34	33	66.949994(72)	133(4) ms	β⁺, p (0.5%)	⁶⁶Ge	5/2−#
⁶⁸Se	34	34	67.94182524(53)	35.5(7) s	β⁺	⁶⁸As	0+
⁶⁹Se	34	35	68.9394148(16)	27.4(2) s	β⁺ (99.95%)	⁶⁹As	1/2−
⁶⁹Se	34	35	68.9394148(16)	27.4(2) s	β⁺, p (.052%)	⁶⁸Ge	1/2−
^69m1Se	38.85(22) keV			2.0(2) μs	IT	⁶⁹Se	5/2−
^69m2Se	574.0(4) keV			955(16) ns	IT	⁶⁹Se	9/2+
⁷⁰Se	34	36	69.9335155(17)	41.1(3) min	β⁺	⁷⁰As	0+
⁷¹Se	34	37	70.9322094(30)	4.74(5) min	β⁺	⁷¹As	(5/2−)
^71m1Se	48.79(5) keV			5.6(7) μs	IT	⁷¹Se	(1/2−)
^71m2Se	260.48(10) keV			19.0(5) μs	IT	⁷¹Se	(9/2+)
⁷²Se	34	38	71.9271405(21)	8.40(8) d	EC	⁷²As	0+
⁷³Se	34	39	72.9267549(80)	7.15(9) h	β⁺	⁷³As	9/2+
^73mSe	25.71(4) keV			39.8(17) min	IT (72.6%)	⁷³Se	3/2−
^73mSe	25.71(4) keV			39.8(17) min	β⁺ (27.4%)	⁷³As	3/2−
⁷⁴Se	34	40	73.922475933(15)	Observationally Stable ^{[n 9]}			0+	0.0086(3)
⁷⁵Se	34	41	74.922522870(78)	119.78(3) d	EC	⁷⁵As	5/2+
⁷⁶Se	34	42	75.919213702(17)	Stable			0+	0.0923(7)
⁷⁷Se	34	43	76.919914150(67)	Stable			1/2−	0.0760(7)
^77mSe	161.9223(10) keV			17.36(5) s	IT	⁷⁷Se	7/2+
⁷⁸Se	34	44	77.91730924(19)	Stable			0+	0.2369 (22)
⁷⁹Se ^{[n 10]}	34	45	78.91849925(24)	3.27(28)×10⁵ y	β⁻	⁷⁹Br	7/2+
^79mSe	95.77(3) keV			3.900(18) min	IT (99.94%)	⁷⁹Se	1/2−
^79mSe	95.77(3) keV			3.900(18) min	β⁻ (0.056%)	⁷⁹Br	1/2−
⁸⁰Se	34	46	79.9165218(10)	Observationally Stable^{[n 11]}			0+	0.4980(36)
⁸¹Se	34	47	80.9179930(10)	18.45(12) min	β⁻	⁸¹Br	1/2−
^81mSe	103.00(6) keV			57.28(2) min	IT (99.95%)	⁸¹Se	7/2+
^81mSe	103.00(6) keV			57.28(2) min	β⁻ (.051%)	⁸¹Br	7/2+
⁸²Se^{[n 12]}	34	48	81.91669953(50)	8.76(15)×10¹⁹ y	β⁻β⁻	⁸²Kr	0+	0.0882(15)
⁸³Se	34	49	82.9191186(33)	22.25(4) min	β⁻	⁸³Br	9/2+
^83mSe	228.92(7) keV			70.1(4) s	β⁻	⁸³Br	1/2−
⁸⁴Se	34	50	83.9184668(21)	3.26(10) min	β⁻	⁸⁴Br	0+
⁸⁵Se	34	51	84.9222608(28)	32.9(3) s	β⁻	⁸⁵Br	(5/2)+
⁸⁶Se	34	52	85.9243117(27)	14.3(3) s	β⁻	⁸⁶Br	0+
⁸⁶Se	34	52	85.9243117(27)	14.3(3) s	β⁻, n?	⁸⁵Br	0+
⁸⁷Se	34	53	86.9286886(24)	5.50(6) s	β⁻ (99.50%)	⁸⁷Br	(3/2+)
⁸⁷Se	34	53	86.9286886(24)	5.50(6) s	β⁻, n (0.60%)	⁸⁶Br	(3/2+)
⁸⁸Se	34	54	87.9314175(36)	1.53(6) s	β⁻ (99.01%)	⁸⁸Br	0+
⁸⁸Se	34	54	87.9314175(36)	1.53(6) s	β⁻, n (0.99%)	⁸⁷Br	0+
⁸⁹Se	34	55	88.9366691(40)	430(50) ms	β⁻ (92.2%)	⁸⁹Br	5/2+#
⁸⁹Se	34	55	88.9366691(40)	430(50) ms	β⁻, n (7.8%)	⁸⁸Br	5/2+#
⁹⁰Se	34	56	89.94010(35)	210(80) ms	β⁻	⁹⁰Br	0+
⁹⁰Se	34	56	89.94010(35)	210(80) ms	β⁻, n?	⁸⁹Br	0+
⁹¹Se	34	57	90.94570(47)	270(50) ms	β⁻ (79%)	⁹¹Br	1/2+#
					β⁻, n (21%)	⁹⁰Br
					β⁻, 2n?	⁸⁹Br
⁹²Se	34	58	91.94984(43)#	90# ms [>300 ns]	β⁻?	⁹²Br	0+
					β⁻, n?	⁹¹Br
					β⁻, 2n?	⁹⁰Br
^92mSe	3072(2) keV			15.7(7) μs	IT	⁹²Se	(9−)
⁹³Se	34	59	92.95614(43)#	130# ms [>300 ns]	β⁻?	⁹³Br	1/2+#
					β⁻, n?	⁹²Br
					β⁻, 2n?	⁹¹Br
^93mSe	678.2(7) keV			420(100) ns	IT	⁹³Se
⁹⁴Se	34	60	93.96049(54)#	50# ms [>300 ns]	β⁻?	⁹⁴Br	0+
					β⁻, n?	⁹³Br
					β⁻, 2n?	⁹²Br
^94mSe	2430.0(6) keV			680(50) ns	IT	⁹⁴Se	(7−)
⁹⁵Se	34	61	94.96730(54)#	70# ms [>400 ns]	β⁻?	⁹⁵Br	3/2+#
					β⁻, n?	⁹⁴Br
					β⁻, 2n?	⁹³Br
⁹⁶Se^[7]	34	62
⁹⁷Se^[7]	34	63
This table header & footer: view

↑ ^mSe – 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.
1 2 # – 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.
↑ Believed to decay by β⁺β⁺ to ⁷⁴Ge with a half-life over 2.3×10¹⁸ y.
↑ Long-lived fission product
↑ Believed to decay by β⁻β⁻ to ⁸⁰Kr
↑ Primordial radionuclide

Use of radioisotopes

The isotope selenium-75 has radiopharmaceutical uses. For example, it is used in high-dose-rate endorectal brachytherapy, as an alternative to iridium-192.^[8]

In paleobiogeochemistry, the ratio in amount of selenium-82 to selenium-76 (i.e, the value of δ^82/76Se) can be used to track down the redox conditions on Earth during the Neoproterozoic era in order to gain a deeper understanding of the rapid oxygenation that trigger the emergence of complex organisms.^[9]^[10]

Related Research Articles

Protactinium (₉₁Pa) has no stable isotopes. The four naturally occurring isotopes allow a standard atomic weight to be given.

Thallium (₈₁Tl) has 41 isotopes with atomic masses that range from 176 to 216. ²⁰³Tl and ²⁰⁵Tl are the only stable isotopes and ²⁰⁴Tl is the most stable radioisotope with a half-life of 3.78 years. ²⁰⁷Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes. All isotopes of thallium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.

Naturally occurring tungsten (₇₄W) consists of five isotopes. Four are considered stable (¹⁸²W, ¹⁸³W, ¹⁸⁴W, and ¹⁸⁶W) and one is slightly radioactive, ¹⁸⁰W, with an extremely long half-life of 1.8 ± 0.2 exayears (10¹⁸ years). On average, two alpha decays of ¹⁸⁰W occur per gram of natural tungsten per year, so for most practical purposes, ¹⁸⁰W can be considered stable. Theoretically, all five can decay into isotopes of element 72 (hafnium) by alpha emission, but only ¹⁸⁰W has been observed to do so. The other naturally occurring isotopes have not been observed to decay (they are observationally stable), and lower bounds for their half-lives have been established:

Naturally occurring gadolinium (₆₄Gd) is composed of 6 stable isotopes, ¹⁵⁴Gd, ¹⁵⁵Gd, ¹⁵⁶Gd, ¹⁵⁷Gd, ¹⁵⁸Gd and ¹⁶⁰Gd, and 1 radioisotope, ¹⁵²Gd, with ¹⁵⁸Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of ¹⁶⁰Gd has never been observed; only a lower limit on its half-life of more than 1.3×10²¹ years has been set experimentally.

Naturally occurring europium (₆₃Eu) is composed of two isotopes, ¹⁵¹Eu and ¹⁵³Eu, with ¹⁵³Eu being the most abundant (52.2% natural abundance). While ¹⁵³Eu is observationally stable (theoretically can undergo alpha decay with half-life over 5.5×10¹⁷ years), ¹⁵¹Eu was found in 2007 to be unstable and undergo alpha decay. The half-life is measured to be (4.62 ± 0.95(stat.) ± 0.68(syst.)) × 10¹⁸ years which corresponds to 1 alpha decay per two minutes in every kilogram of natural europium. Besides the natural radioisotope ¹⁵¹Eu, 36 artificial radioisotopes have been characterized, with the most stable being ¹⁵⁰Eu with a half-life of 36.9 years, ¹⁵²Eu with a half-life of 13.516 years, ¹⁵⁴Eu with a half-life of 8.593 years, and ¹⁵⁵Eu with a half-life of 4.7612 years. The majority of the remaining radioactive isotopes, which range from ¹³⁰Eu to ¹⁷⁰Eu, have half-lives that are less than 12.2 seconds. This element also has 18 metastable isomers, with the most stable being ^150mEu (t_1/2 12.8 hours), ^152m1Eu (t_1/2 9.3116 hours) and ^152m5Eu (t_1/2 96 minutes).

Naturally occurring neodymium (₆₀Nd) is composed of 5 stable isotopes, ¹⁴²Nd, ¹⁴³Nd, ¹⁴⁵Nd, ¹⁴⁶Nd and ¹⁴⁸Nd, with ¹⁴²Nd being the most abundant (27.2% natural abundance), and 2 long-lived radioisotopes, ¹⁴⁴Nd and ¹⁵⁰Nd. In all, 33 radioisotopes of neodymium have been characterized up to now, with the most stable being naturally occurring isotopes ¹⁴⁴Nd (alpha decay, a half-life (t_1/2) of 2.29×10¹⁵ years) and ¹⁵⁰Nd (double beta decay, t_1/2 of 7×10¹⁸ years), and for practical purposes they can be considered to be stable as well. All of the remaining radioactive isotopes have half-lives that are less than 12 days, and the majority of these have half-lives that are less than 70 seconds; the most stable artificial isotope is ¹⁴⁷Nd with a half-life of 10.98 days. This element also has 13 known meta states with the most stable being ^139mNd (t_1/2 5.5 hours), ^135mNd (t_1/2 5.5 minutes) and ^133m1Nd (t_1/2 ~70 seconds).

Naturally occurring cerium (₅₈Ce) is composed of 4 stable isotopes: ¹³⁶Ce, ¹³⁸Ce, ¹⁴⁰Ce, and ¹⁴²Ce, with ¹⁴⁰Ce being the most abundant and the only one theoretically stable; ¹³⁶Ce, ¹³⁸Ce, and ¹⁴²Ce are predicted to undergo double beta decay but this process has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being ¹⁴⁴Ce, with a half-life of 284.893 days; ¹³⁹Ce, with a half-life of 137.640 days and ¹⁴¹Ce, with a half-life of 32.501 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days and the majority of these have half-lives that are less than 10 minutes. This element also has 10 meta states.

Naturally occurring lanthanum (₅₇La) is composed of one stable (¹³⁹La) and one radioactive (¹³⁸La) isotope, with the stable isotope, ¹³⁹La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being ¹³⁸La, with a half-life of 1.02×10¹¹ years; ¹³⁷La, with a half-life of 60,000 years and ¹⁴⁰La, with a half-life of 1.6781 days. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these have half-lives that are less than 1 minute. This element also has 12 nuclear isomers, the longest-lived of which is ^132mLa, with a half-life of 24.3 minutes. Lighter isotopes mostly decay to isotopes of barium and heavy ones mostly decay to isotopes of cerium. ¹³⁸La can decay to both.

Naturally occurring barium (₅₆Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×10²¹ years (about 10¹¹ times the age of the universe).

Naturally occurring xenon (₅₄Xe) consists of seven stable isotopes and two very long-lived isotopes. Double electron capture has been observed in ¹²⁴Xe and double beta decay in ¹³⁶Xe, which are among the longest measured half-lives of all nuclides. The isotopes ¹²⁶Xe and ¹³⁴Xe are also predicted to undergo double beta decay, but this process has never been observed in these isotopes, so they are considered to be stable. Beyond these stable forms, 32 artificial unstable isotopes and various isomers have been studied, the longest-lived of which is ¹²⁷Xe with a half-life of 36.345 days. All other isotopes have half-lives less than 12 days, most less than 20 hours. The shortest-lived isotope, ¹⁰⁸Xe, has a half-life of 58 μs, and is the heaviest known nuclide with equal numbers of protons and neutrons. Of known isomers, the longest-lived is ^131mXe with a half-life of 11.934 days. ¹²⁹Xe is produced by beta decay of ¹²⁹I ; ^131mXe, ¹³³Xe, ^133mXe, and ¹³⁵Xe are some of the fission products of both ²³⁵U and ²³⁹Pu, so are used as indicators of nuclear explosions.

Tin (₅₀Sn) is the element with the greatest number of stable isotopes. This is probably related to the fact that 50 is a "magic number" of protons. In addition, twenty-nine unstable tin isotopes are known, including tin-100 (¹⁰⁰Sn) and tin-132 (¹³²Sn), which are both "doubly magic". The longest-lived tin radioisotope is tin-126 (¹²⁶Sn), with a half-life of 230,000 years. The other 28 radioisotopes have half-lives of less than a year.

Natural palladium (₄₆Pd) is composed of six stable isotopes, ¹⁰²Pd, ¹⁰⁴Pd, ¹⁰⁵Pd, ¹⁰⁶Pd, ¹⁰⁸Pd, and ¹¹⁰Pd, although ¹⁰²Pd and ¹¹⁰Pd are theoretically unstable. The most stable radioisotopes are ¹⁰⁷Pd with a half-life of 6.5 million years, ¹⁰³Pd with a half-life of 17 days, and ¹⁰⁰Pd with a half-life of 3.63 days. Twenty-three other radioisotopes have been characterized with atomic weights ranging from 90.949 u (⁹¹Pd) to 128.96 u (¹²⁹Pd). Most of these have half-lives that are less than 30 minutes except ¹⁰¹Pd, ¹⁰⁹Pd, and ¹¹²Pd.

Naturally occurring ruthenium (₄₄Ru) is composed of seven stable isotopes. Additionally, 27 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are ¹⁰⁶Ru, with a half-life of 373.59 days; ¹⁰³Ru, with a half-life of 39.26 days and ⁹⁷Ru, with a half-life of 2.9 days.

Naturally occurring niobium (₄₁Nb) is composed of one stable isotope (⁹³Nb). The most stable radioisotope is ⁹²Nb with a half-life of 34.7 million years. The next longest-lived niobium isotopes are ⁹⁴Nb and ⁹¹Nb with a half-life of 680 years. There is also a meta state of ⁹³Nb at 31 keV whose half-life is 16.13 years. Twenty-seven other radioisotopes have been characterized. Most of these have half-lives that are less than two hours, except ⁹⁵Nb, ⁹⁶Nb and ⁹⁰Nb. The primary decay mode before stable ⁹³Nb is electron capture and the primary mode after is beta emission with some neutron emission occurring in ^104–110Nb.

Naturally occurring zirconium (₄₀Zr) is composed of four stable isotopes (of which one may in the future be found radioactive), and one very long-lived radioisotope (⁹⁶Zr), a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×10¹⁹ years; it can also undergo single beta decay, which is not yet observed, but the theoretically predicted value of t_1/2 is 2.4×10²⁰ years. The second most stable radioisotope is ⁹³Zr, which has a half-life of 1.53 million years. Thirty other radioisotopes have been observed. All have half-lives less than a day except for ⁹⁵Zr (64.02 days), ⁸⁸Zr (83.4 days), and ⁸⁹Zr (78.41 hours). The primary decay mode is electron capture for isotopes lighter than ⁹²Zr, and the primary mode for heavier isotopes is beta decay.

The alkaline earth metal strontium (₃₈Sr) has four stable, naturally occurring isotopes: ⁸⁴Sr (0.56%), ⁸⁶Sr (9.86%), ⁸⁷Sr (7.0%) and ⁸⁸Sr (82.58%). Its standard atomic weight is 87.62(1).

Bromine (₃₅Br) has two stable isotopes, ⁷⁹Br and ⁸¹Br, and 35 known radioisotopes, the most stable of which is ⁷⁷Br, with a half-life of 57.036 hours.

Arsenic (₃₃As) has 32 known isotopes and at least 10 isomers. Only one of these isotopes, ⁷⁵As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is ⁷³As with a half-life of 80 days.

Copper (₂₉Cu) has two stable isotopes, ⁶³Cu and ⁶⁵Cu, along with 28 radioisotopes. The most stable radioisotope is ⁶⁷Cu with a half-life of 61.83 hours. Most of the others have half-lives under a minute. Unstable copper isotopes with atomic masses below 63 tend to undergo β⁺ decay, while isotopes with atomic masses above 65 tend to undergo β⁻ decay. ⁶⁴Cu decays by both β⁺ and β⁻.

Naturally occurring scandium (₂₁Sc) is composed of one stable isotope, ⁴⁵Sc. Twenty-seven radioisotopes have been characterized, with the most stable being ⁴⁶Sc with a half-life of 83.8 days, ⁴⁷Sc with a half-life of 3.35 days, and ⁴⁸Sc with a half-life of 43.7 hours and ⁴⁴Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound ³⁹Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being ^44m2Sc.

References

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↑ The half-life of ⁷⁹Se Archived September 27, 2011, at the Wayback Machine
↑ Jorg, Gerhard; Buhnemann, Rolf; Hollas, Simon; Kivel, Niko; Kossert, Karsten; Van Winckel, Stefaan; Gostomski, Christoph Lierse v. (2010). "Preparation of radiochemically pure ⁷⁹Se and highly precise determination of its half-life". Applied Radiation and Isotopes. 68 (12): 2339–51. doi:10.1016/j.apradiso.2010.05.006. PMID 20627600.
↑ 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.
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↑ Shoemaker T; Vuong T; Glickman H; Kaifi S; Famulari G; Enger SA (2019). "Dosimetric Considerations for Ytterbium-169, Selenium-75, and Iridium-192 Radioisotopes in High-Dose-Rate Endorectal Brachytherapy". Int J Radiat Oncol Biol Phys. 105 (4): 875–883. doi:10.1016/j.ijrobp.2019.07.003. PMID 31330175. S2CID 198170324.
↑ Pogge von Strandmann, Philip A. E.; Stüeken, Eva E.; Elliott, Tim; Poulton, Simon W.; Dehler, Carol M.; Canfield, Don E.; Catling, David C. (2015-12-18). "Selenium isotope evidence for progressive oxidation of the Neoproterozoic biosphere". Nature Communications. 6 (1): 10157. doi: 10.1038/ncomms10157 . ISSN 2041-1723. PMC 4703861 . PMID 26679529.
↑ Stüeken, Eva E. "Selenium isotopes as a biogeochemical proxy in deep time" (PDF). core.ac.uk.

Isotope masses from:
- 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
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry . 75 (6): 683–800. doi: 10.1351/pac200375060683 .
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry . 78 (11): 2051–2066. doi: 10.1351/pac200678112051 .

"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
Half-life, spin, and isomer data selected from the following sources.
- 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
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

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[6] Se – Excited nuclear isomer.

[8] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-9] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[10] Bold half-life – nearly stable, half-life longer than age of universe.

[TNN-11] 1 2 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[12] Modes of decay:
EC: Electron capture
IT: Isomeric transition
n: Neutron emission
p: Proton emission

[13] Bold symbol as daughter – Daughter product is stable.

[14] ( ) spin value – Indicates spin with weak assignment arguments.

[15] Believed to decay by β⁺β⁺ to ⁷⁴Ge with a half-life over 2.3×10¹⁸ y.

[16] Long-lived fission product

[17] Believed to decay by β⁻β⁻ to ⁸⁰Kr

[18] Primordial radionuclide

[NUBASE2020-1] 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] "Standard Atomic Weights: Selenium". CIAAW. 2013.

[CIAAW2021-3] 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.

[life-4] The half-life of ⁷⁹Se Archived September 27, 2011, at the Wayback Machine

[5] Jorg, Gerhard; Buhnemann, Rolf; Hollas, Simon; Kivel, Niko; Kossert, Karsten; Van Winckel, Stefaan; Gostomski, Christoph Lierse v. (2010). "Preparation of radiochemically pure ⁷⁹Se and highly precise determination of its half-life". Applied Radiation and Isotopes. 68 (12): 2339–51. doi:10.1016/j.apradiso.2010.05.006. PMID 20627600.

[AME2020_II-7] 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.

[shimizu2024-19] 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). doi:10.1103/PhysRevC.109.044313.

[20] Shoemaker T; Vuong T; Glickman H; Kaifi S; Famulari G; Enger SA (2019). "Dosimetric Considerations for Ytterbium-169, Selenium-75, and Iridium-192 Radioisotopes in High-Dose-Rate Endorectal Brachytherapy". Int J Radiat Oncol Biol Phys. 105 (4): 875–883. doi:10.1016/j.ijrobp.2019.07.003. PMID 31330175. S2CID 198170324.

[21] Pogge von Strandmann, Philip A. E.; Stüeken, Eva E.; Elliott, Tim; Poulton, Simon W.; Dehler, Carol M.; Canfield, Don E.; Catling, David C. (2015-12-18). "Selenium isotope evidence for progressive oxidation of the Neoproterozoic biosphere". Nature Communications. 6 (1): 10157. doi: 10.1038/ncomms10157 . ISSN 2041-1723. PMC 4703861 . PMID 26679529.

[22] Stüeken, Eva E. "Selenium isotopes as a biogeochemical proxy in deep time" (PDF). core.ac.uk.

[1]

[2]

[3]

[4]

[5]

[n 1]

[6]

[n 2]

[n 3]

[n 4]

[n 5]

[n 6]

[n 7]

[n 8]

[n 9]

[n 10]

[n 11]

[n 12]

[7]

[8]

[9]

[10]

EC:	Electron capture
IT:	Isomeric transition
n:	Neutron emission
p:	Proton emission

Isotopes of selenium

Contents

List of isotopes

Use of radioisotopes

Related Research Articles

References