Isotopes of terbium

Naturally occurring terbium (65Tb) is composed of one stable isotope, 159Tb. Thirty-seven radioisotopes have been characterized, with the most stable being 158Tb with a half-life of 180 years, 157Tb with a half-life of 71 years, and 160Tb 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 156m1Tb (t1/2 = 24.4 hours), 154m2Tb (t1/2 = 22.7 hours) and 154m1Tb (t1/2 = 9.4 hours).

The primary decay mode before the most abundant stable isotope, 159Tb, is electron capture, and the primary mode behind is beta decay. The primary decay products before 159Tb are element Gd (gadolinium) isotopes, and the primary products after 159Tb are element Dy (dysprosium) isotopes.

List of isotopes

 * 135Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 70
 * 0.94(+33−22) ms
 * (7/2−)
 * 136Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 71
 * 135.96138(64)#
 * 0.2# s
 * 137Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 72
 * 136.95598(64)#
 * 600# ms
 * 11/2−#
 * rowspan=2|138Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 73
 * rowspan=2|137.95316(43)#
 * rowspan=2|800# ms [>200 ns]
 * β+
 * 138Gd
 * rowspan=2|
 * rowspan=2|
 * p
 * 137Gd
 * 139Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 74
 * 138.94829(32)#
 * 1.6(2) s
 * β+
 * 139Gd
 * 11/2−#
 * rowspan=2|140Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 75
 * rowspan=2|139.94581(86)
 * rowspan=2|2.4(2) s
 * β+ (99.74%)
 * 140Gd
 * rowspan=2|5
 * rowspan=2|
 * β+, p (.26%)
 * 139Eu
 * 141Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 76
 * 140.94145(11)
 * 3.5(2) s
 * β+
 * 141Gd
 * (5/2−)
 * style="text-indent:1em" | 141mTb
 * colspan="3" style="text-indent:2em" | 0(200)# keV
 * 7.9(6) s
 * β+
 * 141Gd
 * 11/2−#
 * rowspan=3|142Tb
 * rowspan=3 style="text-align:right" | 65
 * rowspan=3 style="text-align:right" | 77
 * rowspan=3|141.93874(32)#
 * rowspan=3|597(17) ms
 * β+ (96.8(4)%)
 * rowspan=2|142Gd
 * rowspan=3|1+
 * rowspan=3|
 * EC (3.2(4)%)
 * β+, p
 * 141Eu
 * rowspan=2 style="text-indent:1em" | 142m1Tb
 * rowspan=2 colspan="3" style="text-indent:2em" | 280.2(10) keV
 * rowspan=2|303(17) ms
 * IT (99.5%)
 * 142Tb
 * rowspan=2|(5−)
 * rowspan=2|
 * β+ (.5%)
 * 142Gd
 * style="text-indent:1em" | 142m2Tb
 * colspan="3" style="text-indent:2em" | 621.4(11) keV
 * 15(4) μs
 * 143Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 78
 * 142.93512(6)
 * 12(1) s
 * β+
 * 143Gd
 * (11/2−)
 * style="text-indent:1em" | 143mTb
 * colspan="3" style="text-indent:2em" | 0(100)# keV
 * <21 s
 * β+
 * 143Gd
 * 5/2+#
 * rowspan=2|144Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 79
 * rowspan=2|143.93305(3)
 * rowspan=2|~1 s
 * β+
 * 144Gd
 * rowspan=2|1+
 * rowspan=2|
 * β+, p (rare)
 * 143Eu
 * rowspan=3 style="text-indent:1em" | 144m1Tb
 * rowspan=3 colspan="3" style="text-indent:2em" | 396.9(5) keV
 * rowspan=3|4.25(15) s
 * IT (66%)
 * 144Tb
 * rowspan=3|(6−)
 * rowspan=3|
 * β+ (34%)
 * 144Gd
 * β+, p (<1%)
 * 143Eu
 * style="text-indent:1em" | 144m2Tb
 * colspan="3" style="text-indent:2em" | 476.2(5) keV
 * 2.8(3) μs
 * (8−)
 * style="text-indent:1em" | 144m3Tb
 * colspan="3" style="text-indent:2em" | 517.1(5) keV
 * 670(60) ns
 * (9+)
 * style="text-indent:1em" | 144m4Tb
 * colspan="3" style="text-indent:2em" | 544.5(6) keV
 * <300 ns
 * (10+)
 * 145Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 80
 * 144.92927(6)
 * 20# min
 * β+
 * 145Gd
 * (3/2+)
 * style="text-indent:1em" | 145mTb
 * colspan="3" style="text-indent:2em" | 0(100)# keV
 * 30.9(7) s
 * β+
 * 145Gd
 * (11/2−)
 * 146Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 81
 * 145.92725(5)
 * 8(4) s
 * β+
 * 146Gd
 * 1+
 * style="text-indent:1em" | 146m1Tb
 * colspan="3" style="text-indent:2em" | 150(100)# keV
 * 24.1(5) s
 * β+
 * 146Gd
 * 5−
 * style="text-indent:1em" | 146m2Tb
 * colspan="3" style="text-indent:2em" | 930(100)# keV
 * 1.18(2) ms
 * (10+)
 * 147Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 82
 * 146.924045(13)
 * 1.64(3) h
 * β+
 * 147Gd
 * 1/2+#
 * style="text-indent:1em" | 147mTb
 * colspan="3" style="text-indent:2em" | 50.6(9) keV
 * 1.87(5) min
 * β+
 * 147Gd
 * (11/2)−
 * 148Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 83
 * 147.924272(15)
 * 60(1) min
 * β+
 * 148Gd
 * 2−
 * style="text-indent:1em" | 148m1Tb
 * colspan="3" style="text-indent:2em" | 90.1(3) keV
 * 2.20(5) min
 * β+
 * 148Gd
 * (9)+
 * style="text-indent:1em" | 148m2Tb
 * colspan="3" style="text-indent:2em" | 8618.6(10) keV
 * 1.310(7) μs
 * (27+)
 * rowspan=2|149Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 84
 * rowspan=2|148.923246(5)
 * rowspan=2|4.118(25) h
 * β+ (83.3%)
 * 149Gd
 * rowspan=2|1/2+
 * rowspan=2|
 * α (16.7%)
 * 145Eu
 * rowspan=2 style="text-indent:1em" | 149mTb
 * rowspan=2 colspan="3" style="text-indent:2em" | 35.78(13) keV
 * rowspan=2|4.16(4) min
 * β+ (99.97%)
 * 149Gd
 * rowspan=2|11/2−
 * rowspan=2|
 * α (.022%)
 * 145Eu
 * rowspan=2|150Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 85
 * rowspan=2|149.923660(8)
 * rowspan=2|3.48(16) h
 * β+ (99.95%)
 * 150Gd
 * rowspan=2|(2−)
 * rowspan=2|
 * α (.05%)
 * 146Eu
 * rowspan=2 style="text-indent:1em" | 150mTb
 * rowspan=2 colspan="3" style="text-indent:2em" | 457(29) keV
 * rowspan=2|5.8(2) min
 * β+
 * 150Gd
 * rowspan=2|9+
 * rowspan=2|
 * IT (rare)
 * 150Tb
 * rowspan=2|151Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 86
 * rowspan=2|150.923103(5)
 * rowspan=2|17.609(1) h
 * β+ (99.99%)
 * 151Gd
 * rowspan=2|1/2(+)
 * rowspan=2|
 * α (.0095%)
 * 147Eu
 * rowspan=2 style="text-indent:1em" | 151mTb
 * rowspan=2 colspan="3" style="text-indent:2em" | 99.54(6) keV
 * rowspan=2|25(3) s
 * IT (93.8%)
 * 151Tb
 * rowspan=2|(11/2−)
 * rowspan=2|
 * β+ (6.2%)
 * 151Gd
 * rowspan=2|152Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 87
 * rowspan=2|151.92407(4)
 * rowspan=2|17.8784(95) h
 * β+
 * 152Gd
 * rowspan=2|2−
 * rowspan=2|
 * α (7×10−7%)
 * 148Eu
 * style="text-indent:1em" | 152m1Tb
 * colspan="3" style="text-indent:2em" | 342.15(16) keV
 * 0.96 μs
 * 5−
 * rowspan=2 style="text-indent:1em" | 152m2Tb
 * rowspan=2 colspan="3" style="text-indent:2em" | 501.74(19) keV
 * rowspan=2|4.2(1) min
 * IT (78.8%)
 * 152Tb
 * rowspan=2|8+
 * rowspan=2|
 * β+ (21.2%)
 * 152Gd
 * 153Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 88
 * 152.923435(5)
 * 2.34(1) d
 * β+
 * 153Gd
 * 5/2+
 * style="text-indent:1em" | 153mTb
 * colspan="3" style="text-indent:2em" | 163.175(5) keV
 * 186(4) μs
 * 11/2−
 * rowspan=2|154Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 89
 * rowspan=2|153.92468(5)
 * rowspan=2|21.5(4) h
 * β+ (99.9%)
 * 154Gd
 * rowspan=2|0(+#)
 * rowspan=2|
 * β− (.1%)
 * 154Dy
 * rowspan=3 style="text-indent:1em" | 154m1Tb
 * rowspan=3 colspan="3" style="text-indent:2em" | 12(7) keV
 * rowspan=3|9.4(4) h
 * β+ (78.2%)
 * 154Gd
 * rowspan=3|3−
 * rowspan=3|
 * IT (21.8%)
 * 154Tb
 * β− (.1%)
 * 154Dy
 * style="text-indent:1em" | 154m2Tb
 * colspan="3" style="text-indent:2em" | 200(150)# keV
 * 22.7(5) h
 * 7−
 * style="text-indent:1em" | 154m3Tb
 * colspan="3" style="text-indent:2em" | 0+Z keV
 * 513(42) ns
 * 155Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 90
 * 154.923505(13)
 * 5.32(6) d
 * EC
 * 155Gd
 * 3/2+
 * rowspan=2|156Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|155.924747(5)
 * rowspan=2|5.35(10) d
 * β+
 * 156Gd
 * rowspan=2|3−
 * rowspan=2|
 * β− (rare)
 * 156Dy
 * style="text-indent:1em" | 156m1Tb
 * colspan="3" style="text-indent:2em" | 54(3) keV
 * 24.4(10) h
 * IT
 * 156Tb
 * (7−)
 * style="text-indent:1em" | 156m2Tb
 * colspan="3" style="text-indent:2em" | 88.4(2) keV
 * 5.3(2) h
 * (0+)
 * 157Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 92
 * 156.9240246(27)
 * 71(7) y
 * EC
 * 157Gd
 * 3/2+
 * rowspan=2|158Tb
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|157.9254131(28)
 * rowspan=2|180(11) y
 * β+ (83.4%)
 * 158Gd
 * rowspan=2|3−
 * rowspan=2|
 * β− (16.6%)
 * 158Dy
 * rowspan=3 style="text-indent:1em" | 158m1Tb
 * rowspan=3 colspan="3" style="text-indent:2em" | 110.3(12) keV
 * rowspan=3|10.70(17) s
 * IT (99.39%)
 * 158Tb
 * rowspan=3|0−
 * rowspan=3|
 * β− (.6%)
 * 158Dy
 * β+ (.01%)
 * 158Gd
 * style="text-indent:1em" | 158m2Tb
 * colspan="3" style="text-indent:2em" | 388.37(15) keV
 * 0.40(4) ms
 * 7−
 * 159Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 94
 * 158.9253468(27)
 * colspan=3 align=center|Stable
 * 3/2+
 * 1.0000
 * 160Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 95
 * 159.9271676(27)
 * 72.3(2) d
 * β−
 * 160Dy
 * 3−
 * 161Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 96
 * 160.9275699(28)
 * 6.906(19) d
 * β−
 * 161Dy
 * 3/2+
 * 162Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 97
 * 161.92949(4)
 * 7.60(15) min
 * β−
 * 162Dy
 * 1−
 * 163Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 98
 * 162.930648(5)
 * 19.5(3) min
 * β−
 * 163Dy
 * 3/2+
 * 164Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 99
 * 163.93335(11)
 * 3.0(1) min
 * β−
 * 164Dy
 * (5+)
 * 165Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 100
 * 164.93488(21)#
 * 2.11(10) min
 * β−
 * 165mDy
 * 3/2+#
 * 166Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 101
 * 165.93799(11)
 * 25.6(22) s
 * β−
 * 166Dy
 * 167Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 102
 * 166.94005(43)#
 * 19.4(27) s
 * β−
 * 167Dy
 * 3/2+#
 * 168Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 103
 * 167.94364(54)#
 * 8.2(13) s
 * β−
 * 168Dy
 * 4−#
 * 169Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 104
 * 168.94622(64)#
 * 5.13(32) s
 * β−
 * 169Dy
 * 3/2+#
 * 170Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 105
 * 169.95025(75)#
 * 960(78) ms
 * β−
 * 170Dy
 * 171Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 106
 * 170.95330(86)#
 * 1.23(10) s
 * β−
 * 171Dy
 * 3/2+#
 * 172Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 107
 * 760(190) ms
 * β−
 * 172Dy
 * 6+#
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|157.9254131(28)
 * rowspan=2|180(11) y
 * β+ (83.4%)
 * 158Gd
 * rowspan=2|3−
 * rowspan=2|
 * β− (16.6%)
 * 158Dy
 * rowspan=3 style="text-indent:1em" | 158m1Tb
 * rowspan=3 colspan="3" style="text-indent:2em" | 110.3(12) keV
 * rowspan=3|10.70(17) s
 * IT (99.39%)
 * 158Tb
 * rowspan=3|0−
 * rowspan=3|
 * β− (.6%)
 * 158Dy
 * β+ (.01%)
 * 158Gd
 * style="text-indent:1em" | 158m2Tb
 * colspan="3" style="text-indent:2em" | 388.37(15) keV
 * 0.40(4) ms
 * 7−
 * 159Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 94
 * 158.9253468(27)
 * colspan=3 align=center|Stable
 * 3/2+
 * 1.0000
 * 160Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 95
 * 159.9271676(27)
 * 72.3(2) d
 * β−
 * 160Dy
 * 3−
 * 161Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 96
 * 160.9275699(28)
 * 6.906(19) d
 * β−
 * 161Dy
 * 3/2+
 * 162Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 97
 * 161.92949(4)
 * 7.60(15) min
 * β−
 * 162Dy
 * 1−
 * 163Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 98
 * 162.930648(5)
 * 19.5(3) min
 * β−
 * 163Dy
 * 3/2+
 * 164Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 99
 * 163.93335(11)
 * 3.0(1) min
 * β−
 * 164Dy
 * (5+)
 * 165Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 100
 * 164.93488(21)#
 * 2.11(10) min
 * β−
 * 165mDy
 * 3/2+#
 * 166Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 101
 * 165.93799(11)
 * 25.6(22) s
 * β−
 * 166Dy
 * 167Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 102
 * 166.94005(43)#
 * 19.4(27) s
 * β−
 * 167Dy
 * 3/2+#
 * 168Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 103
 * 167.94364(54)#
 * 8.2(13) s
 * β−
 * 168Dy
 * 4−#
 * 169Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 104
 * 168.94622(64)#
 * 5.13(32) s
 * β−
 * 169Dy
 * 3/2+#
 * 170Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 105
 * 169.95025(75)#
 * 960(78) ms
 * β−
 * 170Dy
 * 171Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 106
 * 170.95330(86)#
 * 1.23(10) s
 * β−
 * 171Dy
 * 3/2+#
 * 172Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 107
 * 760(190) ms
 * β−
 * 172Dy
 * 6+#
 * style="text-align:right" | 65
 * style="text-align:right" | 104
 * 168.94622(64)#
 * 5.13(32) s
 * β−
 * 169Dy
 * 3/2+#
 * 170Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 105
 * 169.95025(75)#
 * 960(78) ms
 * β−
 * 170Dy
 * 171Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 106
 * 170.95330(86)#
 * 1.23(10) s
 * β−
 * 171Dy
 * 3/2+#
 * 172Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 107
 * 760(190) ms
 * β−
 * 172Dy
 * 6+#
 * 172Tb
 * style="text-align:right" | 65
 * style="text-align:right" | 107
 * 760(190) ms
 * β−
 * 172Dy
 * 6+#
 * 6+#