Isotopes of cerium

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.

Main isotopes of cerium (₅₈Ce)

Iso­tope Decay abun­dance half-life (t1/2) mode pro­duct ^134Ce syn 3.16 d ε ^134La ^136Ce 0.186% stable ^138Ce 0.251% stable ^139Ce syn 137.640 d ε ^139La ^140Ce 88.449% stable ^141Ce syn 32.501 d β^− ^141Pr ^142Ce 11.114% stable ^143Ce syn 33.039 h β^− ^143Pr ^144Ce syn 284.893 d β^− ^144Pr
Standard atomic weight Ar°(Ce)
	140.116±0.001 140.12±0.01 (abridged)^[1]^[2]
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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)
	Excitation energy							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+
					β^+, p	^121Ba
^123Ce	58	65	122.93540(32)#	3.8(2) s	β^+	^123La	(5/2)(+#)
					β^+, p	^122Ba
^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−)
					β^+, p	^124Ba
^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−
					β^+ (.779%)	^137La
^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^[n 11]			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 12]			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

1. ^mCe – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. Modes of decay:

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

6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. Theorized to undergo β⁺β⁺ decay to ¹³⁶Ba with a half-life over 38×10¹⁵ years
9. Theorized to undergo β⁺β⁺ decay to ¹³⁸Ba with a half-life over 150×10¹² years
10. Fission product
11. Theoretically capable of spontaneous fission
12. Theorized to undergo β⁻β⁻ decay to ¹⁴²Nd or α decay to ¹³⁸Ba with a half-life over 2.9×10¹⁸ years^[3][4]

References

1. "Standard Atomic Weights: Cerium". CIAAW. 1995.
2. 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.
3. 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.
4. 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. doi:10.1140/epja/i2019-12823-2.

• 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.