Isotopes of terbium
Nuclides with atomic number of 65 but with different mass numbers
Naturally occurring terbium (65 Tb) is composed of one stable isotope , 159 Tb. Thirty-seven radioisotopes have been characterized, with the most stable being 158 Tb with a half-life of 180 years, 157 Tb with a half-life of 71 years, and 160 Tb with a half-life of 72.3 days. All of the remaining radioactive isotopes have half-lives that are less than 6.907 days, and the majority of these have half-lives that are less than 24 seconds. This element also has 27 meta states , with the most stable being 156m1 Tb (t1/2 = 24.4 hours), 154m2 Tb (t1/2 = 22.7 hours) and 154m1 Tb (t1/2 = 9.4 hours).
The primary decay mode before the most abundant stable isotope, 159 Tb, is electron capture , and the primary mode behind is beta decay . The primary decay products before 159 Tb are element Gd (gadolinium ) isotopes, and the primary products after 159 Tb are element Dy (dysprosium ) isotopes.
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] [n 7]
Spin andparity [n 8] [n 4]
Isotopic abundance
Excitation energy[n 4]
135 Tb
65
70
0.94(+33−22) ms
(7/2−)
136 Tb
65
71
135.96138(64)#
0.2# s
137 Tb
65
72
136.95598(64)#
600# ms
11/2−#
138 Tb
65
73
137.95316(43)#
800# ms [>200 ns]
β+
138 Gd
p
137 Gd
139 Tb
65
74
138.94829(32)#
1.6(2) s
β+
139 Gd
11/2−#
140 Tb
65
75
139.94581(86)
2.4(2) s
β+ (99.74%)
140 Gd
5
β+ , p (.26%)
139 Eu
141 Tb
65
76
140.94145(11)
3.5(2) s
β+
141 Gd
(5/2−)
141m Tb
0(200)# keV
7.9(6) s
β+
141 Gd
11/2−#
142 Tb
65
77
141.93874(32)#
597(17) ms
β+ (96.8(4)%)
142 Gd
1+
EC (3.2(4)%)
β+ , p
141 Eu
142m1 Tb
280.2(10) keV
303(17) ms
IT (99.5%)
142 Tb
(5−)
β+ (.5%)
142 Gd
142m2 Tb
621.4(11) keV
15(4) μs
143 Tb
65
78
142.93512(6)
12(1) s
β+
143 Gd
(11/2−)
143m Tb
0(100)# keV
<21 s
β+
143 Gd
5/2+#
144 Tb
65
79
143.93305(3)
~1 s
β+
144 Gd
1+
β+ , p (rare)
143 Eu
144m1 Tb
396.9(5) keV
4.25(15) s
IT (66%)
144 Tb
(6−)
β+ (34%)
144 Gd
β+ , p (<1%)
143 Eu
144m2 Tb
476.2(5) keV
2.8(3) μs
(8−)
144m3 Tb
517.1(5) keV
670(60) ns
(9+)
144m4 Tb
544.5(6) keV
<300 ns
(10+)
145 Tb
65
80
144.92927(6)
20# min
β+
145 Gd
(3/2+)
145m Tb
0(100)# keV
30.9(7) s
β+
145 Gd
(11/2−)
146 Tb
65
81
145.92725(5)
8(4) s
β+
146 Gd
1+
146m1 Tb
150(100)# keV
24.1(5) s
β+
146 Gd
5−
146m2 Tb
930(100)# keV
1.18(2) ms
(10+)
147 Tb
65
82
146.924045(13)
1.64(3) h
β+
147 Gd
1/2+#
147m Tb
50.6(9) keV
1.87(5) min
β+
147 Gd
(11/2)−
148 Tb
65
83
147.924272(15)
60(1) min
β+
148 Gd
2−
148m1 Tb
90.1(3) keV
2.20(5) min
β+
148 Gd
(9)+
148m2 Tb
8618.6(10) keV
1.310(7) μs
(27+)
149 Tb
65
84
148.923246(5)
4.118(25) h
β+ (83.3%)
149 Gd
1/2+
α (16.7%)
145 Eu
149m Tb
35.78(13) keV
4.16(4) min
β+ (99.97%)
149 Gd
11/2−
α (.022%)
145 Eu
150 Tb
65
85
149.923660(8)
3.48(16) h
β+ (99.95%)
150 Gd
(2−)
α (.05%)
146 Eu
150m Tb
457(29) keV
5.8(2) min
β+
150 Gd
9+
IT (rare)
150 Tb
151 Tb
65
86
150.923103(5)
17.609(1) h
β+ (99.99%)
151 Gd
1/2(+)
α (.0095%)
147 Eu
151m Tb
99.54(6) keV
25(3) s
IT (93.8%)
151 Tb
(11/2−)
β+ (6.2%)
151 Gd
152 Tb
65
87
151.92407(4)
17.8784(95) h[4]
β+
152 Gd
2−
α (7×10−7 %)
148 Eu
152m1 Tb
342.15(16) keV
0.96 μs
5−
152m2 Tb
501.74(19) keV
4.2(1) min
IT (78.8%)
152 Tb
8+
β+ (21.2%)
152 Gd
153 Tb
65
88
152.923435(5)
2.34(1) d
β+
153 Gd
5/2+
153m Tb
163.175(5) keV
186(4) μs
11/2−
154 Tb
65
89
153.92468(5)
21.5(4) h
β+ (99.9%)
154 Gd
0(+#)
β− (.1%)
154 Dy
154m1 Tb
12(7) keV
9.4(4) h
β+ (78.2%)
154 Gd
3−
IT (21.8%)
154 Tb
β− (.1%)
154 Dy
154m2 Tb
200(150)# keV
22.7(5) h
7−
154m3 Tb
0+Z keV
513(42) ns
155 Tb
65
90
154.923505(13)
5.32(6) d
EC
155 Gd
3/2+
156 Tb
65
91
155.924747(5)
5.35(10) d
β+
156 Gd
3−
β− (rare)
156 Dy
156m1 Tb
54(3) keV
24.4(10) h
IT
156 Tb
(7−)
156m2 Tb
88.4(2) keV
5.3(2) h
(0+)
157 Tb
65
92
156.9240246(27)
71(7) y
EC
157 Gd
3/2+
158 Tb
65
93
157.9254131(28)
180(11) y
β+ (83.4%)
158 Gd
3−
β− (16.6%)
158 Dy
158m1 Tb
110.3(12) keV
10.70(17) s
IT (99.39%)
158 Tb
0−
β− (.6%)
158 Dy
β+ (.01%)
158 Gd
158m2 Tb
388.37(15) keV
0.40(4) ms
7−
159 Tb[n 9]
65
94
158.9253468(27)
Stable
3/2+
1.0000
160 Tb
65
95
159.9271676(27)
72.3(2) d
β−
160 Dy
3−
161 Tb[n 9]
65
96
160.9275699(28)
6.906(19) d
β−
161 Dy
3/2+
162 Tb
65
97
161.92949(4)
7.60(15) min
β−
162 Dy
1−
163 Tb
65
98
162.930648(5)
19.5(3) min
β−
163 Dy
3/2+
164 Tb
65
99
163.93335(11)
3.0(1) min
β−
164 Dy
(5+)
165 Tb
65
100
164.93488(21)#
2.11(10) min
β−
165m Dy
3/2+#
166 Tb
65
101
165.93799(11)
25.6(22) s
β−
166 Dy
167 Tb
65
102
166.94005(43)#
19.4(27) s
β−
167 Dy
3/2+#
168 Tb
65
103
167.94364(54)#
8.2(13) s
β−
168 Dy
4−#
169 Tb
65
104
168.94622(64)#
5.13(32) s
β−
169 Dy
3/2+#
170 Tb
65
105
169.95025(75)#
960(78) ms
β−
170 Dy
171 Tb
65
106
170.95330(86)#
1.23(10) s
β−
171 Dy
3/2+#
172 Tb
65
107
760(190) ms
β−
172 Dy
6+#
This table header & footer:
^ m Tb – 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 c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
^
Modes of decay:
^ Bold italics symbol as daughter – Daughter product is nearly stable.
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ a b Fission product
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: Terbium" . CIAAW . 2021.
^ 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 .
^ Collins, S.M.; Köster, U.; Robinson, A.P.; Ivanov, P.; Cocolios, T.E.; Russell, B.; Fenwick, A.J.; Bernerd, C.; Stegemann, S.; Johnston, K.; Gerami, A.M.; Chrysalidis, K.; Mohamud, H.; Ramirez, N.; Bhaisare, A.; Mewburn-Crook, J.; Cullen, D.M.; Pietras, B.; Pells, S.; Dockx, K.; Stucki, N.; Regan, P.H. (2023). "Determination of the Terbium-152 half-life from mass-separated samples from CERN-ISOLDE and assessment of the radionuclide purity" . Applied Radiation and Isotopes . 202 . Elsevier BV: 111044. doi :10.1016/j.apradiso.2023.111044 . ISSN 0969-8043 . PMID 37797447 .
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