Naturally occurring cerium (58 Ce) is composed of 4 stable isotopes : 136 Ce, 138 Ce, 140 Ce, and 142 Ce, with 140 Ce being the most abundant (88.48% natural abundance ) and the only one theoretically stable; 136 Ce, 138 Ce, and 142 Ce 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 144 Ce, with a half-life of 284.893 days; 139 Ce, with a half-life of 137.640 days and 141 Ce, 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 (119 Ce) to 157 u (157 Ce).
List of isotopes
Nuclide[ n 1]
Z
N
Isotopic mass (Da ) [ 4] [ n 2] [ n 3]
Half-life [ 1] [ n 4]
Decay mode [ 1] [ n 5]
Daughter isotope [ n 6]
Spin andparity [ 1] [ n 7] [ n 4]
Natural abundance (mole fraction)
Excitation energy
Normal proportion[ 1]
Range of variation
121 Ce
58
63
120.94344(43)#
1.1(1) s
β+ (99%)
121 La
5/2(+#)
β+ , p (1%)
121 La
122 Ce
58
64
121.93787(43)#
2# s
β+
122 La
0+
123 Ce
58
65
122.93528(32)#
3.8(2) s
β+ (?%)
123 La
(5/2)(+#)
β+ , p (?%)
122 Ba
124 Ce
58
66
123.93031(32)#
9.1(12) s
β+
124 La
0+
125 Ce
58
67
124.92844(21)#
9.7(3) s
β+ (?%)
125 La
(7/2−)
β+ , p (?%)
124 Ba
125m Ce
93.6(4) keV
13(10) s
IT
125 Ce
(1/2+)
126 Ce
58
68
125.923971(30)
51.0(3) s
β+
126 La
0+
127 Ce
58
69
126.922727(31)
34(2) s
β+
127 La
(1/2+)
127m1 Ce
7.3(11) keV
28.6(7) s
β+
127 La
(5/2+)
127m2 Ce
36.9(11) keV
>10 μs
IT
127 Ce
(7/2−)
128 Ce
58
70
127.918911(30)
3.93(2) min
β+
128 La
0+
129 Ce
58
71
128.918102(30)
3.5(3) min
β+
129 La
(5/2+)
130 Ce
58
72
129.914736(30)
22.9(5) min
β+
130 La
0+
130m Ce
2453.6(3) keV
100(8) ns
IT
130 Ce
7−
131 Ce
58
73
130.914429(35)
10.3(3) min
β+
131 La
7/2+
131m Ce
63.09(9) keV
5.4(4) min
β+
131 La
(1/2+)
132 Ce
58
74
131.911466(22)
3.51(11) h
β+
132 La
0+
132m Ce
2341.15(21) keV
9.4(3) ms
IT
132 Ce
8−
133 Ce
58
75
132.911520(18)
97(4) min
β+
133 La
1/2+
133m Ce
37.2(7) keV
5.1(3) h
β+
133 La
9/2−
134 Ce
58
76
133.908928(22)
3.16(4) d
EC
134 La
0+
134m Ce
3208.6(4) keV
308(5) ns
IT
134 Ce
10+
135 Ce
58
77
134.909161(11)
17.7(3) h
β+
135 La
1/2+
135m Ce
445.81(21) keV
20(1) s
IT
135 Ce
(11/2−)
136 Ce
58
78
135.90712926(35)
Observationally Stable [ n 8]
0+
0.00186(2)
136m Ce
3095.0(6) keV
1.96(9) μs
IT
136 Ce
10+
137 Ce
58
79
136.90776242(39)
9.0(3) h
β+
137 La
3/2+
137m Ce
254.29(5) keV
34.4(3) h
IT (99.21%)
137 Ce
11/2−
β+ (0.79%)
137 La
138 Ce
58
80
137.90599418(54)
Observationally Stable [ n 9]
0+
0.00251(2)
138m Ce
2129.28(12) keV
8.73(20) ms
IT
138 Ce
7-
139 Ce
58
81
138.9066470(22)
137.642(20) d
EC
139 La
3/2+
139m Ce
754.24(8) keV
57.58(32) s
IT
139 Ce
11/2−
140 Ce[ n 10]
58
82
139.9054484(14)
Stable
0+
0.88449(51)
140m Ce
2107.854(24) keV
7.3(15) μs
IT
140 Ce
6+
141 Ce[ n 10]
58
83
140.9082860(14)
32.505(10) d
β−
141 Pr
7/2−
142 Ce[ n 10]
58
84
141.9092502(26)
Observationally Stable [ n 11] [ 5]
0+
0.11114(51)
143 Ce[ n 10]
58
85
142.9123920(26)
33.039(6) h
β−
143 Pr
3/2−
144 Ce[ n 10]
58
86
143.9136528(30)
284.886(25) d
β−
144 Pr
0+
145 Ce
58
87
144.917265(36)
3.01(6) min
β−
145 Pr
5/2−#
146 Ce
58
88
145.918812(16)
13.49(16) min
β−
146 Pr
0+
147 Ce
58
89
146.9226899(92)
56.4(10) s
β−
147 Pr
(5/2−)
148 Ce
58
90
147.924424(12)
56.8(3) s
β−
148 Pr
0+
149 Ce
58
91
148.928427(11)
4.94(4) s
β−
149 Pr
3/2−#
150 Ce
58
92
149.930384(13)
6.05(7) s
β−
150 Pr
0+
151 Ce
58
93
150.934272(19)
1.76(6) s
β−
151 Pr
(3/2−)
152 Ce
58
94
151.93668(22)#
1.42(2) s
β−
152 Pr
0+
153 Ce
58
95
152.94105(22)#
865(25) ms
β−
153 Pr
3/2−#
154 Ce
58
96
153.94394(22)#
722(14) ms
β−
154 Pr
0+
155 Ce
58
97
154.94871(32)#
313(7) ms
β−
155 Pr
5/2−#
156 Ce
58
98
155.95188(32)#
233(9) ms
β−
156 Pr
0+
157 Ce
58
99
156.95713(43)#
175(41) ms
β−
157 Pr
7/2+#
158 Ce
58
100
157.96077(43)#
99(93) ms
β−
158 Pr
0+
This table header & footer:
^ m Ce – 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:
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ Theorized to undergo β+ β+ decay to 136 Ba with a half-life over 3.2×1016 years
^ Theorized to undergo β+ β+ decay to 138 Ba with a half-life over 4.4×1016 years
^ a b c d e Fission product
^ Theorized to undergo β− β− decay to 142 Nd or α decay to 138 Ba with a half-life over 2.9×1018 years
References
^ a b c d e 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 .
^ 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 .
^ 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 .
Isotope masses from:
Isotopic compositions and standard atomic masses from:
"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 .
Group
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Period
Hydrogen and alkali metals
Alkaline earth metals
Pnictogens
Chalcogens
Halogens
Noble gases
①
1
2
②
3
4
5
6
7
8
9
10
③
11
12
13
14
15
16
17
18
④
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
⑤
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
⑥
55
56
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
⑦
87
88
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
⑧
119
120
57
58
59
60
61
62
63
64
65
66
67
68
69
70
89
90
91
92
93
94
95
96
97
98
99
100
101
102