Isotopes of tellurium

Isotopes of tellurium (₅₂Te)
Standard atomic weight Ar°(Te)
	127.60±0.03; 127.60±0.03 (abridged);
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Last updated January 16, 2024

There are 39 known isotopes and 17 nuclear isomers of tellurium (₅₂Te), with atomic masses that range from 104 to 142. These are listed in the table below.

Naturally-occurring tellurium on Earth consists of eight isotopes. Two of these have been found to be radioactive: ¹²⁸Te and ¹³⁰Te undergo double beta decay with half-lives of, respectively, 2.2×10²⁴ (2.2 septillion) years (the longest half-life of all nuclides proven to be radioactive)^[5] and 8.2×10²⁰ (820 quintillion) years. The longest-lived artificial radioisotope of tellurium is ¹²¹Te with a half-life of about 19 days. Several nuclear isomers have longer half-lives, the longest being ^121mTe with a half-life of 154 days.

The very-long-lived radioisotopes ¹²⁸Te and ¹³⁰Te are the two most common isotopes of tellurium. Of elements with at least one stable isotope, only indium and rhenium likewise have a radioisotope in greater abundance than a stable one.

It has been claimed that electron capture of ¹²³Te was observed, but more recent measurements of the same team have disproved this.^[6] The half-life of ¹²³Te is longer than 9.2 × 10¹⁶ years, and probably much longer.^[6]

¹²⁴Te can be used as a starting material in the production of radionuclides by a cyclotron or other particle accelerators. Some common radionuclides that can be produced from tellurium-124 are iodine-123 and iodine-124.

The short-lived isotope ¹³⁵Te (half-life 19 seconds) is produced as a fission product in nuclear reactors. It decays, via two beta decays, to ¹³⁵Xe, the most powerful known neutron absorber, and the cause of the iodine pit phenomenon.

With the exception of beryllium, tellurium is the second lightest element observed to have isotopes capable of undergoing alpha decay, with isotopes ¹⁰⁴Te to ¹⁰⁹Te being seen to undergo this mode of decay. Some lighter elements, namely those in the vicinity of ⁸Be, have isotopes with delayed alpha emission (following proton or beta emission) as a rare branch.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life ^{[n 4]}^{[n 5]}	Decay mode ^{[n 6]}	Daughter isotope ^{[n 7]}	Spin and parity ^{[n 8]}^{[n 5]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy			Half-life ^{[n 4]}^{[n 5]}	Decay mode ^{[n 6]}	Daughter isotope ^{[n 7]}	Spin and parity ^{[n 8]}^{[n 5]}	Normal proportion	Range of variation
¹⁰⁴Te^[7]	52	52		<18 ns	α	¹⁰⁰Sn	0+
¹⁰⁵Te	52	53	104.94364(54)#	620(70) ns	α	¹⁰¹Sn	5/2+#
¹⁰⁶Te	52	54	105.93750(14)	70(20) µs [70(+20−10) µs]	α	¹⁰²Sn	0+
¹⁰⁷Te	52	55	106.93501(32)#	3.1(1) ms	α (70%)	¹⁰³Sn	5/2+#
¹⁰⁷Te	52	55	106.93501(32)#	3.1(1) ms	β⁺ (30%)	¹⁰⁷Sb	5/2+#
¹⁰⁸Te	52	56	107.92944(11)	2.1(1) s	α (49%)	¹⁰⁴Sn	0+
					β⁺ (48.5%)	¹⁰⁸Sb
					β⁺, p (2.4%)	¹⁰⁷Sn
					β⁺, α (.065%)	¹⁰⁴In
¹⁰⁹Te	52	57	108.92742(7)	4.6(3) s	β⁺ (86.99%)	¹⁰⁹Sb	(5/2+)
					β⁺, p (9.4%)	¹⁰⁸Sn
					α (7.9%)	¹⁰⁵Sn
					β⁺, α (.005%)	¹⁰⁵In
¹¹⁰Te	52	58	109.92241(6)	18.6(8) s	β⁺ (99.99%)	¹¹⁰Sb	0+
¹¹⁰Te	52	58	109.92241(6)	18.6(8) s	β⁺, p (.003%)	¹⁰⁹Sn	0+
¹¹¹Te	52	59	110.92111(8)	19.3(4) s	β⁺	¹¹¹Sb	(5/2)+#
¹¹¹Te	52	59	110.92111(8)	19.3(4) s	β⁺, p (rare)	¹¹⁰Sn	(5/2)+#
¹¹²Te	52	60	111.91701(18)	2.0(2) min	β⁺	¹¹²Sb	0+
¹¹³Te	52	61	112.91589(3)	1.7(2) min	β⁺	¹¹³Sb	(7/2+)
¹¹⁴Te	52	62	113.91209(3)	15.2(7) min	β⁺	¹¹⁴Sb	0+
¹¹⁵Te	52	63	114.91190(3)	5.8(2) min	β⁺	¹¹⁵Sb	7/2+
^115m1Te	10(7) keV			6.7(4) min	β⁺	¹¹⁵Sb	(1/2)+
^115m1Te	10(7) keV			6.7(4) min	IT	¹¹⁵Te	(1/2)+
^115m2Te	280.05(20) keV			7.5(2) µs			11/2−
¹¹⁶Te	52	64	115.90846(3)	2.49(4) h	β⁺	¹¹⁶Sb	0+
¹¹⁷Te	52	65	116.908645(14)	62(2) min	β⁺	¹¹⁷Sb	1/2+
^117mTe	296.1(5) keV			103(3) ms	IT	¹¹⁷Te	(11/2−)
¹¹⁸Te	52	66	117.905828(16)	6.00(2) d	EC	¹¹⁸Sb	0+
¹¹⁹Te	52	67	118.906404(9)	16.05(5) h	β⁺	¹¹⁹Sb	1/2+
^119mTe	260.96(5) keV			4.70(4) d	β⁺ (99.99%)	¹¹⁹Sb	11/2−
^119mTe	260.96(5) keV			4.70(4) d	IT (.008%)	¹¹⁹Te	11/2−
¹²⁰Te	52	68	119.90402(1)	Observationally Stable ^{[n 9]}			0+	9(1)×10⁻⁴
¹²¹Te	52	69	120.904936(28)	19.16(5) d	β⁺	¹²¹Sb	1/2+
^121mTe	293.991(22) keV			154(7) d	IT (88.6%)	¹²¹Te	11/2−
^121mTe	293.991(22) keV			154(7) d	β⁺ (11.4%)	¹²¹Sb	11/2−
¹²²Te	52	70	121.9030439(16)	Stable			0+	0.0255(12)
¹²³Te	52	71	122.9042700(16)	Observationally Stable^{[n 10]}			1/2+	0.0089(3)
^123mTe	247.47(4) keV			119.2(1) d	IT	¹²³Te	11/2−
¹²⁴Te	52	72	123.9028179(16)	Stable			0+	0.0474(14)
¹²⁵Te^{[n 11]}	52	73	124.9044307(16)	Stable			1/2+	0.0707(15)
^125mTe	144.772(9) keV			57.40(15) d	IT	¹²⁵Te	11/2−
¹²⁶Te	52	74	125.9033117(16)	Stable			0+	0.1884(25)
¹²⁷Te^{[n 11]}	52	75	126.9052263(16)	9.35(7) h	β⁻	¹²⁷I	3/2+
^127mTe	88.26(8) keV			109(2) d	IT (97.6%)	¹²⁷Te	11/2−
^127mTe	88.26(8) keV			109(2) d	β⁻ (2.4%)	¹²⁷I	11/2−
¹²⁸Te^{[n 11]}^{[n 12]}	52	76	127.9044631(19)	2.2(3)×10²⁴ y^{[n 13]}	β⁻β⁻	¹²⁸Xe	0+	0.3174(8)
^128mTe	2790.7(4) keV			370(30) ns			10+
¹²⁹Te^{[n 11]}	52	77	128.9065982(19)	69.6(3) min	β⁻	¹²⁹I	3/2+
^129mTe	105.50(5) keV			33.6(1) d	β⁻ (36%)	¹²⁹I	11/2−
^129mTe	105.50(5) keV			33.6(1) d	IT (64%)	¹²⁹Te	11/2−
¹³⁰Te^{[n 11]}^{[n 12]}	52	78	129.9062244(21)	8.2(0.2 (stat.), 0.6 (syst.))×10²⁰ y	β⁻β⁻	¹³⁰Xe	0+	0.3408(62)
^130m1Te	2146.41(4) keV			115(8) ns			(7)−
^130m2Te	2661(7) keV			1.90(8) µs			(10+)
^130m3Te	4375.4(18) keV			261(33) ns
¹³¹Te^{[n 11]}	52	79	130.9085239(21)	25.0(1) min	β⁻	¹³¹I	3/2+
^131mTe	182.250(20) keV			30(2) h	β⁻ (77.8%)	¹³¹I	11/2−
^131mTe	182.250(20) keV			30(2) h	IT (22.2%)	¹³¹Te	11/2−
¹³²Te^{[n 11]}	52	80	131.908553(7)	3.204(13) d	β⁻	¹³²I	0+
¹³³Te	52	81	132.910955(26)	12.5(3) min	β⁻	¹³³I	(3/2+)
^133mTe	334.26(4) keV			55.4(4) min	β⁻ (82.5%)	¹³³I	(11/2−)
^133mTe	334.26(4) keV			55.4(4) min	IT (17.5%)	¹³³Te	(11/2−)
¹³⁴Te	52	82	133.911369(11)	41.8(8) min	β⁻	¹³⁴I	0+
^134mTe	1691.34(16) keV			164.1(9) ns			6+
¹³⁵Te^{[n 14]}	52	83	134.91645(10)	19.0(2) s	β⁻	¹³⁵I	(7/2−)
^135mTe	1554.88(17) keV			510(20) ns			(19/2−)
¹³⁶Te	52	84	135.92010(5)	17.63(8) s	β⁻ (98.7%)	¹³⁶I	0+
¹³⁶Te	52	84	135.92010(5)	17.63(8) s	β⁻, n (1.3%)	¹³⁵I	0+
¹³⁷Te	52	85	136.92532(13)	2.49(5) s	β⁻ (97.01%)	¹³⁷I	3/2−#
¹³⁷Te	52	85	136.92532(13)	2.49(5) s	β⁻, n (2.99%)	¹³⁶I	3/2−#
¹³⁸Te	52	86	137.92922(22)#	1.4(4) s	β⁻ (93.7%)	¹³⁸I	0+
¹³⁸Te	52	86	137.92922(22)#	1.4(4) s	β⁻, n (6.3%)	¹³⁷I	0+
¹³⁹Te	52	87	138.93473(43)#	500 ms [>300 ns]#	β⁻	¹³⁹I	5/2−#
¹³⁹Te	52	87	138.93473(43)#	500 ms [>300 ns]#	β⁻, n	¹³⁸I	5/2−#
¹⁴⁰Te	52	88	139.93885(32)#	300 ms [>300 ns]#	β⁻	¹⁴⁰I	0+
¹⁴⁰Te	52	88	139.93885(32)#	300 ms [>300 ns]#	β⁻, n	¹³⁹I	0+
¹⁴¹Te	52	89	140.94465(43)#	100 ms [>300 ns]#	β⁻	¹⁴¹I	5/2−#
¹⁴¹Te	52	89	140.94465(43)#	100 ms [>300 ns]#	β⁻, n	¹⁴⁰I	5/2−#
¹⁴²Te	52	90	141.94908(64)#	50 ms [>300 ns]#	β⁻	¹⁴²I	0+
This table header & footer: view

↑ ^mTe – 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 undergo β⁺β⁺ decay to ¹²⁰Sn with a half-life over 2.2×10¹⁶ years
↑ Believed to undergo β⁺ decay to ¹²³Sb with a half-life over 9.2×10¹⁶ years
1 2 3 4 5 6 7 Fission product
1 2 Primordial radionuclide
↑ Longest measured half-life of any nuclide
↑ Very short-lived fission product, responsible for the iodine pit as precursor of ¹³⁵Xe via ¹³⁵I

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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.

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<span class="mw-page-title-main">Isotopes of iodine</span> Nuclides with atomic number of 53 but with different mass numbers

There are 37 known isotopes of iodine (₅₃I) from ¹⁰⁸I to ¹⁴⁴I; all undergo radioactive decay except ¹²⁷I, which is stable. Iodine is thus a monoisotopic element.

Caesium (₅₅Cs) has 40 known isotopes, making it, along with barium and mercury, one of the elements with the most isotopes. The atomic masses of these isotopes range from 112 to 151. Only one isotope, ¹³³Cs, is stable. The longest-lived radioisotopes are ¹³⁵Cs with a half-life of 2.3 million years, ¹³⁷
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Antimony (₅₁Sb) occurs in two stable isotopes, ¹²¹Sb and ¹²³Sb. There are 35 artificial radioactive isotopes, the longest-lived of which are ¹²⁵Sb, with a half-life of 2.75856 years; ¹²⁴Sb, with a half-life of 60.2 days; and ¹²⁶Sb, with a half-life of 12.35 days. All other isotopes have half-lives less than 4 days, most less than an hour.

Tin (₅₀Sn) is the element with the greatest number of stable isotopes. Moreover, tin is not only the element with the greatest number of observationally stable isotopes, but also the element with the greatest number of theoretically 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.

Indium (₄₉In) consists of two primordial nuclides, with the most common (~ 95.7%) nuclide (¹¹⁵In) being measurably though weakly radioactive. Its spin-forbidden decay has a half-life of 4.41×10¹⁴ years, much longer than the currently accepted age of the Universe.

Naturally occurring cadmium (₄₈Cd) is composed of 8 isotopes. For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decays have not been observed, due to extremely long half-lives. The two natural radioactive isotopes are ¹¹³Cd (beta decay, half-life is 8.04 × 10¹⁵ years) and ¹¹⁶Cd (two-neutrino double beta decay, half-life is 2.8 × 10¹⁹ years). The other three are ¹⁰⁶Cd, ¹⁰⁸Cd (double electron capture), and ¹¹⁴Cd (double beta decay); only lower limits on their half-life times have been set. Three isotopes—¹¹⁰Cd, ¹¹¹Cd, and ¹¹²Cd—are theoretically stable. Among the isotopes absent in natural cadmium, the most long-lived are ¹⁰⁹Cd with a half-life of 462.6 days, and ¹¹⁵Cd with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives that are less than 2.5 hours and the majority of these have half-lives that are less than 5 minutes. This element also has 12 known meta states, with the most stable being ^113mCd (t_1/2 14.1 years), ^115mCd (t_1/2 44.6 days) and ^117mCd (t_1/2 3.36 hours).

Naturally occurring rhodium (₄₅Rh) is composed of only one stable isotope, ¹⁰³Rh. The most stable radioisotopes are ¹⁰¹Rh with a half-life of 3.3 years, ¹⁰²Rh with a half-life of 207 days, and ⁹⁹Rh with a half-life of 16.1 days. Thirty other radioisotopes have been characterized with atomic weights ranging from 88.949 u (⁸⁹Rh) to 121.943 u (¹²²Rh). Most of these have half-lives that are less than an hour except ¹⁰⁰Rh and ¹⁰⁵Rh. There are also numerous meta states with the most stable being ^102mRh (0.141 MeV) with a half-life of about 3.7 years and ^101mRh (0.157 MeV) with a half-life of 4.34 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.

Rubidium (₃₇Rb) has 36 isotopes, with naturally occurring rubidium being composed of just two isotopes; ⁸⁵Rb (72.2%) and the radioactive ⁸⁷Rb (27.8%). Normal mixes of rubidium are radioactive enough to fog photographic film in approximately 30 to 60 days.

Naturally occurring chromium (₂₄Cr) is composed of four stable isotopes; ⁵⁰Cr, ⁵²Cr, ⁵³Cr, and ⁵⁴Cr with ⁵²Cr being the most abundant (83.789% natural abundance). ⁵⁰Cr is suspected of decaying by β⁺β⁺ to ⁵⁰Ti with a half-life of (more than) 1.8×10¹⁷ years. Twenty-two radioisotopes, all of which are entirely synthetic, have been characterized, the most stable being ⁵¹Cr with a half-life of 27.7 days. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority of these have half-lives that are less than 1 minute. This element also has two meta states, ^45mCr, the more stable one, and ^59mCr, the least stable isotope or isomer.

Neptunium (₉₃Np) is usually considered an artificial element, although trace quantities are found in nature, so a standard atomic weight cannot be given. Like all trace or artificial elements, it has no stable isotopes. The first isotope to be synthesized and identified was ²³⁹Np in 1940, produced by bombarding ²³⁸
U with neutrons to produce ²³⁹
U, which then underwent beta decay to ²³⁹
Np.

References

↑ 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.
↑ Alessandrello, A.; Arnaboldi, C.; Brofferio, C.; Capelli, S.; Cremonesi, O.; Fiorini, E.; Nucciotti, A.; Pavan, M.; Pessina, G.; Pirro, S.; Previtali, E.; Sisti, M.; Vanzini, M.; Zanotti, L.; Giuliani, A.; Pedretti, M.; Bucci, C.; Pobes, C. (2003). "New limits on naturally occurring electron capture of 123Te". Physical Review C. 67: 014323. arXiv: hep-ex/0211015 . Bibcode:2003PhRvC..67a4323A. doi:10.1103/PhysRevC.67.014323.
↑ "Standard Atomic Weights: Tellurium". CIAAW. 1969.
↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (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.
↑ Many isotopes are expected to have longer half-lives, but decay has not yet been observed in these, allowing only a lower limit to be placed on their half-lives
1 2 A. Alessandrello; et al. (January 2003). "New Limits on Naturally Occurring Electron Capture of ¹²³Te". Physical Review C. 67 (1): 014323. arXiv: hep-ex/0211015 . Bibcode:2003PhRvC..67a4323A. doi:10.1103/PhysRevC.67.014323. S2CID 119523039.
↑ Auranen, K.; et al. (2018). "Superallowed α decay to doubly magic ¹⁰⁰Sn" (PDF). Physical Review Letters. 121 (18): 182501. Bibcode:2018PhRvL.121r2501A. doi: 10.1103/PhysRevLett.121.182501 . PMID 30444390.

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.
- Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F. (2017-01-01). "Measurement of the two-neutrino double-beta decay half-life of ¹³⁰Te with the CUORE-0 experiment". The European Physical Journal C. 77 (1): 13. arXiv: 1609.01666 . Bibcode:2017EPJC...77...13A. doi:10.1140/epjc/s10052-016-4498-6. ISSN 1434-6044. S2CID 254105128.

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[7] Te – 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.

[16] Believed to undergo β⁺β⁺ decay to ¹²⁰Sn with a half-life over 2.2×10¹⁶ years

[17] Believed to undergo β⁺ decay to ¹²³Sb with a half-life over 9.2×10¹⁶ years

[FP-18] 1 2 3 4 5 6 7 Fission product

[PN-19] 1 2 Primordial radionuclide

[20] Longest measured half-life of any nuclide

[21] Very short-lived fission product, responsible for the iodine pit as precursor of ¹³⁵Xe via ¹³⁵I

[NUBASE2020-1] 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] Alessandrello, A.; Arnaboldi, C.; Brofferio, C.; Capelli, S.; Cremonesi, O.; Fiorini, E.; Nucciotti, A.; Pavan, M.; Pessina, G.; Pirro, S.; Previtali, E.; Sisti, M.; Vanzini, M.; Zanotti, L.; Giuliani, A.; Pedretti, M.; Bucci, C.; Pobes, C. (2003). "New limits on naturally occurring electron capture of 123Te". Physical Review C. 67: 014323. arXiv: hep-ex/0211015 . Bibcode:2003PhRvC..67a4323A. doi:10.1103/PhysRevC.67.014323.

[3] "Standard Atomic Weights: Tellurium". CIAAW. 1969.

[CIAAW2021-4] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (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.

[5] Many isotopes are expected to have longer half-lives, but decay has not yet been observed in these, allowing only a lower limit to be placed on their half-lives

[new_limits-6] 1 2 A. Alessandrello; et al. (January 2003). "New Limits on Naturally Occurring Electron Capture of ¹²³Te". Physical Review C. 67 (1): 014323. arXiv: hep-ex/0211015 . Bibcode:2003PhRvC..67a4323A. doi:10.1103/PhysRevC.67.014323. S2CID 119523039.

[100Sn-15] Auranen, K.; et al. (2018). "Superallowed α decay to doubly magic ¹⁰⁰Sn" (PDF). Physical Review Letters. 121 (18): 182501. Bibcode:2018PhRvL.121r2501A. doi: 10.1103/PhysRevLett.121.182501 . PMID 30444390.

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