Isotopes of cerium

Isotopes of cerium (₅₈Ce)
Standard atomic weight Ar°(Ce)
	140.116±0.001; 140.12±0.01 (abridged);
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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 (88.48% natural abundance) 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.

The isotopes of cerium range in atomic weight from 119 u (¹¹⁹Ce) to 157 u (¹⁵⁷Ce).

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy			Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Normal proportion	Range of variation
¹¹⁹Ce	58	61	118.95276(64)#	200# ms	β⁺	¹¹⁹La	5/2+#
¹²⁰Ce	58	62	119.94664(75)#	250# ms	β⁺	¹²⁰La	0+
¹²¹Ce	58	63	120.94342(54)#	1.1(1) s	β⁺	¹²¹La	(5/2)(+#)
¹²²Ce	58	64	121.93791(43)#	2# s	β⁺	¹²²La	0+
¹²²Ce	58	64	121.93791(43)#	2# s	β⁺, p	¹²¹Ba	0+
¹²³Ce	58	65	122.93540(32)#	3.8(2) s	β⁺	¹²³La	(5/2)(+#)
¹²³Ce	58	65	122.93540(32)#	3.8(2) s	β⁺, p	¹²²Ba	(5/2)(+#)
¹²⁴Ce	58	66	123.93041(32)#	9.1(12) s	β⁺	¹²⁴La	0+
¹²⁵Ce	58	67	124.92844(21)#	9.3(3) s	β⁺	¹²⁵La	(7/2−)
¹²⁵Ce	58	67	124.92844(21)#	9.3(3) s	β⁺, p	¹²⁴Ba	(7/2−)
¹²⁶Ce	58	68	125.92397(3)	51.0(3) s	β⁺	¹²⁶La	0+
¹²⁷Ce	58	69	126.92273(6)	29(2) s	β⁺	¹²⁷La	5/2+#
¹²⁸Ce	58	70	127.91891(3)	3.93(2) min	β⁺	¹²⁸La	0+
¹²⁹Ce	58	71	128.91810(3)	3.5(3) min	β⁺	¹²⁹La	(5/2+)
¹³⁰Ce	58	72	129.91474(3)	22.9(5) min	β⁺	¹³⁰La	0+
^130mCe	2453.6(3) keV			100(8) ns			(7−)
¹³¹Ce	58	73	130.91442(4)	10.2(3) min	β⁺	¹³¹La	(7/2+)
^131mCe	61.8(1) keV			5.0(10) min	β⁺	¹³¹La	(1/2+)
¹³²Ce	58	74	131.911460(22)	3.51(11) h	β⁺	¹³²La	0+
^132mCe	2340.8(5) keV			9.4(3) ms	IT	¹³²Ce	(8−)
¹³³Ce	58	75	132.911515(18)	97(4) min	β⁺	¹³³La	1/2+
^133mCe	37.1(8) keV			4.9(4) d	β⁺	¹³³La	9/2−
¹³⁴Ce	58	76	133.908925(22)	3.16(4) d	EC	¹³⁴La	0+
¹³⁵Ce	58	77	134.909151(12)	17.7(3) h	β⁺	¹³⁵La	1/2(+)
^135mCe	445.8(2) keV			20(1) s	IT	¹³⁵Ce	(11/2−)
¹³⁶Ce	58	78	135.907172(14)	Observationally Stable^{[n 8]}			0+	0.00185(2)	0.00185–0.00186
^136mCe	3095.5(4) keV			2.2(2) μs			10+
¹³⁷Ce	58	79	136.907806(14)	9.0(3) h	β⁺	¹³⁷La	3/2+
^137mCe	254.29(5) keV			34.4(3) h	IT (99.22%)	¹³⁷Ce	11/2−
^137mCe	254.29(5) keV			34.4(3) h	β⁺ (.779%)	¹³⁷La	11/2−
¹³⁸Ce	58	80	137.905991(11)	Observationally Stable^{[n 9]}			0+	0.00251(2)	0.00251–0.00254
^138mCe	2129.17(12) keV			8.65(20) ms	IT	¹³⁸Ce	7-
¹³⁹Ce	58	81	138.906653(8)	137.641(20) d	EC	¹³⁹La	3/2+
^139mCe	754.24(8) keV			56.54(13) s	IT	¹³⁹Ce	11/2−
¹⁴⁰Ce^{[n 10]}	58	82	139.9054387(26)	Stable			0+	0.88450(51)	0.88446–0.88449
^140mCe	2107.85(3) keV			7.3(15) μs			6+
¹⁴¹Ce^{[n 10]}	58	83	140.9082763(26)	32.508(13) d	β⁻	¹⁴¹Pr	7/2−
¹⁴²Ce^{[n 10]}	58	84	141.909244(3)	Observationally Stable^{[n 11]}^[4]^[5]			0+	0.11114(51)	0.11114–0.11114
¹⁴³Ce^{[n 10]}	58	85	142.912386(3)	33.039(6) h	β⁻	¹⁴³Pr	3/2−
¹⁴⁴Ce^{[n 10]}	58	86	143.913647(4)	284.91(5) d	β⁻	^144mPr	0+
¹⁴⁵Ce	58	87	144.91723(4)	3.01(6) min	β⁻	¹⁴⁵Pr	(3/2−)
¹⁴⁶Ce	58	88	145.91876(7)	13.52(13) min	β⁻	¹⁴⁶Pr	0+
¹⁴⁷Ce	58	89	146.92267(3)	56.4(10) s	β⁻	¹⁴⁷Pr	(5/2−)
¹⁴⁸Ce	58	90	147.92443(3)	56(1) s	β⁻	¹⁴⁸Pr	0+
¹⁴⁹Ce	58	91	148.9284(1)	5.3(2) s	β⁻	¹⁴⁹Pr	(3/2−)#
¹⁵⁰Ce	58	92	149.93041(5)	4.0(6) s	β⁻	¹⁵⁰Pr	0+
¹⁵¹Ce	58	93	150.93398(11)	1.02(6) s	β⁻	¹⁵¹Pr	3/2−#
¹⁵²Ce	58	94	151.93654(21)#	1.4(2) s	β⁻	¹⁵²Pr	0+
¹⁵³Ce	58	95	152.94058(43)#	500# ms [>300 ns]	β⁻	¹⁵³Pr	3/2−#
¹⁵⁴Ce	58	96	153.94342(54)#	300# ms [>300 ns]	β⁻	¹⁵⁴Pr	0+
¹⁵⁵Ce	58	97	154.94804(64)#	200# ms [>300 ns]	β⁻	¹⁵⁵Pr	5/2−#
¹⁵⁶Ce	58	98	155.95126(64)#	150# ms	β⁻	¹⁵⁶Pr	0+
¹⁵⁷Ce	58	99	156.95634(75)#	50# ms	β⁻	¹⁵⁷Pr	7/2+#
This table header & footer: view

^ ^mCe – 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).
^ ^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

p: Proton emission
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ Theorized to undergo β⁺β⁺ decay to ¹³⁶Ba with a half-life over 38×10¹⁵ years
^ Theorized to undergo β⁺β⁺ decay to ¹³⁸Ba with a half-life over 150×10¹² years
^ ^a ^b ^c ^d ^e Fission product
^ Theorized to undergo β⁻β⁻ decay to ¹⁴²Nd or α decay to ¹³⁸Ba with a half-life over 2.9×10¹⁸ years

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.
^ "Standard Atomic Weights: Cerium". CIAAW. 1995.
^ 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.
^ 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): 98. doi:10.1088/1674-1137/abddae.
^ Belli, P.; Bernabei, R.; Danevich, F. A.; Incicchitti, A.; Tretyak, V. I. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (140): 4–6. arXiv:1908.11458. Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. S2CID 254103706.