Isotopes of tellurium (₅₂Te)

Main isotopes^[1]			Decay
	abundance	half-life (t_1/2)	mode	product
¹²⁰Te	0.09%	stable
¹²¹Te	synth	16.78 d	ε	¹²¹Sb
¹²²Te	2.55%	stable
¹²³Te	0.89%	stable^[2]
¹²⁴Te	4.74%	stable
¹²⁵Te	7.07%	stable
¹²⁶Te	18.8%	stable
¹²⁷Te	synth	9.35 h	β⁻	¹²⁷I
¹²⁸Te	31.7%	2.2×10²⁴ y	β⁻β⁻	¹²⁸Xe
¹²⁹Te	synth	69.6 min	β⁻	¹²⁹I
¹³⁰Te	34.1%	8.2×10²⁰ y	β⁻β⁻	¹³⁰Xe

Standard atomic weight A_r°(Te)

127.60±0.03^[3]
127.60±0.03 (abridged)^[4]

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.
^ ^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.
^ 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
^ ^a ^b ^c ^d ^e ^f ^g Fission product
^ ^a ^b 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

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; 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.
^ 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
^ ^a ^b 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.

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