Isotopes of thulium

Naturally occurring thulium (₆₉Tm) is composed of one stable isotope, ¹⁶⁹Tm, with 100% natural abundance. Thirty-nine radioisotopes have been characterized from ¹⁴⁴Tm to ¹⁸³Tm; with the most stable are ¹⁷¹Tm with a half-life of 1.92 years, ¹⁷⁰Tm with a half-life of 128.6 days, ¹⁶⁸Tm with a half-life of 93.1 days, and ¹⁶⁷Tm with a half-life of 9.25 days. All of the remaining radioactive isotopes have half-lives that are less than 3 days, with the majority less than 10 minutes. This element also has 26 meta states, with the longest half-lives being ^164mTm (5.1 minutes), ^160m1Tm (75 seconds) and ^155mTm (45 seconds).

The primary decay mode before the stable isotope, ¹⁶⁹Tm, is electron capture to erbium isotopes, and the primary mode after is beta emission to ytterbium isotopes. All isotopes of thulium are either radioactive or, in the case of ¹⁶⁹Tm, observationally stable, meaning that ¹⁶⁹Tm is predicted to be radioactive but decay has not been observed.

List of isotopes

|-id=Thulium-144 | ¹⁴⁴Tm | style="text-align:right" | 69 | style="text-align:right" | 75 | 143.97621(43)# | 2.3(9)&nbsp;μs | p | ¹⁴³Er | (10+) | |-id=Thulium-145 | ¹⁴⁵Tm | style="text-align:right" | 69 | style="text-align:right" | 76 | 144.97039(21)# | 3.17(20)&nbsp;μs | p | ¹⁴⁴Er | (11/2−) | |-id=Thulium-146 | ¹⁴⁶Tm | style="text-align:right" | 69 | style="text-align:right" | 77 | 145.96666(22)# | 155(20)&nbsp;ms | p | ¹⁴⁵Er | (1+) | |-id=Thulium-146m1 | style="text-indent:1em" | ^146m1Tm | colspan="3" style="text-indent:2em" | 304(6)&nbsp;keV | 73(7)&nbsp;ms | p | ¹⁴⁵Er | (5−) | |-id=Thulium-146m2 | style="text-indent:1em" | ^146m2Tm | colspan="3" style="text-indent:2em" | 437(7)&nbsp;keV | 200(3)&nbsp;ms | p | ¹⁴⁵Er | (10+) | |-id=Thulium-147 | rowspan=2|¹⁴⁷Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 78 | rowspan=2|146.9613799(73) | rowspan=2|0.58(3)&nbsp;s | β⁺ (85%) | ¹⁴⁷Er | rowspan=2|11/2− | rowspan=2| |- | p (15%) | ¹⁴⁶Er |-id=Thulium-147m | style="text-indent:1em" | ^147mTm | colspan="3" style="text-indent:2em" | 62(5)&nbsp;keV | 360(40)&nbsp;μs | p | ¹⁴⁶Er | 3/2+ | |-id=Thulium-148 | ¹⁴⁸Tm | style="text-align:right" | 69 | style="text-align:right" | 79 | 147.958384(11) | 0.7(2)&nbsp;s | β⁺ | ¹⁴⁸Er | (10+) | |-id=Thulium-149 | rowspan=2|¹⁴⁹Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 80 | rowspan=2|148.95283(22)# | rowspan=2|0.9(2)&nbsp;s | β⁺ (99.74%) | ¹⁴⁹Er | rowspan=2|11/2− | rowspan=2| |- | β⁺, p (0.26%) | ¹⁴⁸Ho |-id=Thulium-150 | ¹⁵⁰Tm | style="text-align:right" | 69 | style="text-align:right" | 81 | 149.95009(21)# | 3#&nbsp;s | β⁺ | ¹⁵⁰Er | (1+) | |-id=Thulium-150m1 | rowspan=2 style="text-indent:1em" | ^150m1Tm | rowspan=2 colspan="3" style="text-indent:2em" | 140(140)#&nbsp;keV | rowspan=2|2.20(6)&nbsp;s | β⁺ (98.9%) | ¹⁵⁰Er | rowspan=2|(6−) | rowspan=2| |- | β⁺, p (1.1%) | ¹⁴⁹Ho |-id=Thulium-150m2 | style="text-indent:1em" | ^150m2Tm | colspan="3" style="text-indent:2em" | 811(140)# keV | 5.2(3)&nbsp;ms | IT | ^150m1Tm | 10+# | |-id=Thulium-151 | ¹⁵¹Tm | style="text-align:right" | 69 | style="text-align:right" | 82 | 150.945494(21) | 4.17(11)&nbsp;s | β⁺ | ¹⁵¹Er | (11/2−) | |-id=Thulium-151m1 | style="text-indent:1em" | ^151m1Tm | colspan="3" style="text-indent:2em" | 93(6)&nbsp;keV | 6.6(20)&nbsp;s | β⁺ | ¹⁵¹Er | (1/2+) | |-id=Thulium-151m2 | style="text-indent:1em" | ^151m2Tm | colspan="3" style="text-indent:2em" | 2655.67(22)&nbsp;keV | 451(34)&nbsp;ns | IT | ¹⁵¹Tm | (27/2−) | |-id=Thulium-152 | ¹⁵²Tm | style="text-align:right" | 69 | style="text-align:right" | 83 | 151.944476(58) | 8.0(10)&nbsp;s | β⁺ | ¹⁵²Er | (2)− | |-id=Thulium-152m1 | style="text-indent:1em" | ^152m1Tm | colspan="3" style="text-indent:2em" | −100(250)&nbsp;keV | 5.2(6)&nbsp;s | β⁺ | ¹⁵²Er | (9)+ | |-id=Thulium-152m2 | style="text-indent:1em" | ^152m2Tm | colspan="3" style="text-indent:2em" | 2455(250)&nbsp;keV | 301(7)&nbsp;ns | IT | ¹⁵²Tm | (17+) | |-id=Thulium-153 | rowspan=2|¹⁵³Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 84 | rowspan=2|152.942058(13) | rowspan=2|1.48(1)&nbsp;s | α (91%) | ¹⁴⁹Ho | rowspan=2|(11/2−) | rowspan=2| |- | β⁺ (9%) | ¹⁵³Er |-id=Thulium-153m | rowspan=2 style="text-indent:1em" | ^153mTm | rowspan=2 colspan="3" style="text-indent:2em" | 43.2(2)&nbsp;keV | rowspan=2|2.5(2)&nbsp;s | α (92%) | ¹⁴⁹Ho | rowspan=2|(1/2+) | rowspan=2| |- | β⁺ (8%) | ¹⁵³Er |-id=Thulium-154 | rowspan=2|¹⁵⁴Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 85 | rowspan=2|153.941570(15) | rowspan=2|8.1(3)&nbsp;s | β⁺ (54%) | ¹⁵⁴Er | rowspan=2|(2)− | rowspan=2| |- | α (46%) | ¹⁵⁰Ho |-id=Thulium-154m | rowspan=2 style="text-indent:1em" | ^154mTm | rowspan=2 colspan="3" style="text-indent:2em" | 70(50)&nbsp;keV | rowspan=2|3.30(7)&nbsp;s | α (58%) | ¹⁵⁰Ho | rowspan=2|(9)+ | rowspan=2| |- | β⁺ (42%) | ¹⁵⁴Er |-id=Thulium-155 | rowspan=2|¹⁵⁵Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 86 | rowspan=2|154.939210(11) | rowspan=2|21.6(2)&nbsp;s | β⁺ (99.17%) | ¹⁵⁵Er | rowspan=2|11/2− | rowspan=2| |- | α (0.83%) | ¹⁵¹Ho |-id=Thulium-155m | style="text-indent:1em" | ^155mTm | colspan="3" style="text-indent:2em" | 41(6)&nbsp;keV | 45(4)&nbsp;s | β⁺ | ¹⁵⁵Er | 1/2+ | |-id=Thulium-156 | rowspan=2|¹⁵⁶Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 87 | rowspan=2|155.938986(15) | rowspan=2|83.8(18)&nbsp;s | β⁺ (99.94%) | ¹⁵⁶Er | rowspan=2|2− | rowspan=2| |- | α (0.064%) | ¹⁵²Ho |-id=Thulium-156m | style="text-indent:1em" | ^156mTm | colspan="3" style="text-indent:2em" | 400(200)#&nbsp;keV | ~400&nbsp;ns | IT | ¹⁵⁶Tm | (11−) | |-id=Thulium-157 | rowspan=2|¹⁵⁷Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 88 | rowspan=2|156.936973(30) | rowspan=2|3.63(9)&nbsp;min | β⁺ | ¹⁵⁷Er | rowspan=2|1/2+ | rowspan=2| |- | α (7.5%) | ¹⁵³Ho |-id=Thulium-157m | style="text-indent:1em" | ^157mTm | colspan="3" style="text-indent:2em" | 100(50)#&nbsp;keV | 1.6&nbsp;s | | | 7/2−# | |-id=Thulium-158 | ¹⁵⁸Tm | style="text-align:right" | 69 | style="text-align:right" | 89 | 157.936980(27) | 3.98(6)&nbsp;min | β⁺ | ¹⁵⁸Er | 2− | |-id=Thulium-158m | style="text-indent:1em" | ^158mTm | colspan="3" style="text-indent:2em" | 100(50)#&nbsp;keV | ~20&nbsp;s | | | 5−# | |-id=Thulium-159 | ¹⁵⁹Tm | style="text-align:right" | 69 | style="text-align:right" | 90 | 158.934975(30) | 9.13(16)&nbsp;min | β⁺ | ¹⁵⁹Er | 5/2+ | |-id=Thulium-160 | ¹⁶⁰Tm | style="text-align:right" | 69 | style="text-align:right" | 91 | 159.935264(35) | 9.4(3)&nbsp;min | β⁺ | ¹⁶⁰Er | 1− | |-id=Thulium-160m1 | rowspan=2 style="text-indent:1em" | ^160m1Tm | rowspan=2 colspan="3" style="text-indent:2em" | 67(14)&nbsp;keV | rowspan=2|74.5(15)&nbsp;s | IT (85%) | ¹⁶⁰Tm | rowspan=2|(5+) | rowspan=2| |- | β⁺ (15%) | ¹⁶⁰Er |-id=Thulium-160m2 | style="text-indent:1em" | ^160m2Tm | colspan="3" style="text-indent:2em" | 215(52)#&nbsp;keV | ~200&nbsp;ns | IT | ¹⁶⁰Tm | (8) | |-id=Thulium-161 | ¹⁶¹Tm | style="text-align:right" | 69 | style="text-align:right" | 92 | 160.933549(30) | 30.2(8)&nbsp;min | β⁺ | ¹⁶¹Er | 7/2+ | |-id=Thulium-161m1 | style="text-indent:1em" | ^161m1Tm | colspan="3" style="text-indent:2em" | 7.51(24)&nbsp;keV | 5#&nbsp;min | | | (1/2+) | |-id=Thulium-161m2 | style="text-indent:1em" | ^161m2Tm | colspan="3" style="text-indent:2em" | 78.20(3)&nbsp;keV | 110(3)&nbsp;ns | IT | ¹⁶¹Tm | 7/2− | |-id=Thulium-162 | ¹⁶²Tm | style="text-align:right" | 69 | style="text-align:right" | 93 | 161.934001(28) | 21.70(19)&nbsp;min | β⁺ | ¹⁶²Er | 1− | |-id=Thulium-162m | rowspan=2 style="text-indent:1em" | ^162mTm | rowspan=2 colspan="3" style="text-indent:2em" | 130(40)&nbsp;keV | rowspan=2|24.3(17)&nbsp;s | IT (81%) | ¹⁶²Tm | rowspan=2|5+ | rowspan=2| |- | β⁺ (19%) | ¹⁶²Er |-id=Thulium-163 | ¹⁶³Tm | style="text-align:right" | 69 | style="text-align:right" | 94 | 162.9326583(59) | 1.810(5)&nbsp;h | β⁺ | ¹⁶³Er | 1/2+ | |-id=Thulium-163m | style="text-indent:1em" | ^163mTm | colspan="3" style="text-indent:2em" | 86.92(5)&nbsp;keV | 380(30)&nbsp;ns | IT | ¹⁶³Tm | (7/2)− | |-id=Thulium-164 | rowspan=2|¹⁶⁴Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 95 | rowspan=2|163.933538(27) | rowspan=2|2.0(1)&nbsp;min | EC (61%) | rowspan=2|¹⁶⁴Er | rowspan=2|1+ | rowspan=2| |- | β⁺ (39%) |-id=Thulium-164m | rowspan=2 style="text-indent:1em" | ^164mTm | rowspan=2 colspan="3" style="text-indent:2em" | 20(12)&nbsp;keV | rowspan=2|5.1(1)&nbsp;min | IT (~80%) | ¹⁶⁴Tm | rowspan=2|6− | rowspan=2| |- | β⁺ (~20%) | ¹⁶⁴Er |-id=Thulium-165 | ¹⁶⁵Tm | style="text-align:right" | 69 | style="text-align:right" | 96 | 164.9324418(18) | 30.06(3)&nbsp;h | β⁺ | ¹⁶⁵Er | 1/2+ | |-id=Thulium-165m1 | style="text-indent:1em" | ^165m1Tm | colspan="3" style="text-indent:2em" | 80.37(6)&nbsp;keV | 80(3)&nbsp;μs | IT | ¹⁶⁵Tm | 7/2+ | |-id=Thulium-165m2 | style="text-indent:1em" | ^165m2Tm | colspan="3" style="text-indent:2em" | 160.47(6)&nbsp;keV | 9.0(5)&nbsp;μs | IT | ¹⁶⁵Tm | 7/2− | |-id=Thulium-166 | ¹⁶⁶Tm | style="text-align:right" | 69 | style="text-align:right" | 97 | 165.933562(12) | 7.70(3)&nbsp;h | β⁺ | ¹⁶⁶Er | 2+ | |-id=Thulium-166m1 | style="text-indent:1em" | ^166m1Tm | colspan="3" style="text-indent:2em" | 122(7)&nbsp;keV | 348(21)&nbsp;ms | IT | ¹⁶⁶Tm | (6−) | |-id=Thulium-166m2 | style="text-indent:1em" | ^166m2Tm | colspan="3" style="text-indent:2em" | 244(7)&nbsp;keV | 2(1)&nbsp;μs | IT | ¹⁶⁶Tm | (6−) | |-id=Thulium-167 | ¹⁶⁷Tm | style="text-align:right" | 69 | style="text-align:right" | 98 | 166.9328572(14) | 9.25(2)&nbsp;d | EC | ¹⁶⁷Er | 1/2+ | |-id=Thulium-167m1 | style="text-indent:1em" | ^167m1Tm | colspan="3" style="text-indent:2em" | 179.480(19)&nbsp;keV | 1.16(6)&nbsp;μs | IT | ¹⁶⁷Tm | 7/2+ | |-id=Thulium-167m2 | style="text-indent:1em" | ^167m2Tm | colspan="3" style="text-indent:2em" | 292.820(20)&nbsp;keV | 0.9(1)&nbsp;μs | IT | ¹⁶⁷Tm | 7/2− | |-id=Thulium-168 | rowspan=2|¹⁶⁸Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 99 | rowspan=2|167.9341785(18) | rowspan=2|93.1(2)&nbsp;d | β⁺ (99.99%) | ¹⁶⁸Er | rowspan=2|3+ | rowspan=2| |- | β^− (0.010%) | ¹⁶⁸Yb |-id=Thulium-169 | ¹⁶⁹Tm | style="text-align:right" | 69 | style="text-align:right" | 100 | 168.93421896(79) | colspan=3 align=center|Observationally Stable | 1/2+ | 1.0000 |-id=Thulium-169m | style="text-indent:1em" | ^169mTm | colspan="3" style="text-indent:2em" | 316.1463(1)&nbsp;keV | 659.9(23)&nbsp;ns | IT | ¹⁶⁹Tm | 7/2+ | |- | rowspan=2|¹⁷⁰Tm | rowspan=2 style="text-align:right" | 69 | rowspan=2 style="text-align:right" | 101 | rowspan=2|169.93580709(79) | rowspan=2|128.6(3)&nbsp;d | β^− (99.87%) | ¹⁷⁰Yb | rowspan=2|1− | rowspan=2| |- | EC (0.131%) | ¹⁷⁰Er |-id=Thulium-170m | style="text-indent:1em" | ^170mTm | colspan="3" style="text-indent:2em" | 183.197(4)&nbsp;keV | 4.12(13)&nbsp;μs | IT | ¹⁷⁰Tm | 3+ | |-id=Thulium-171 | ¹⁷¹Tm | style="text-align:right" | 69 | style="text-align:right" | 102 | 170.9364352(10) | 1.92(1)&nbsp;y | β^− | ¹⁷¹Yb | 1/2+ | |-id=Thulium-171m1 | style="text-indent:1em" | ^171m1Tm | colspan="3" style="text-indent:2em" | 424.9557(15)&nbsp;keV | 2.60(2)&nbsp;μs | IT | ¹⁷¹Tm | 7/2− | |-id=Thulium-171m2 | style="text-indent:1em" | ^171m2Tm | colspan="3" style="text-indent:2em" | 1674.43(13)&nbsp;keV | 1.7(2)&nbsp;μs | IT | ¹⁷¹Tm | 19/2+ | |-id=Thulium-172 | ¹⁷²Tm | style="text-align:right" | 69 | style="text-align:right" | 103 | 171.9384070(59) | 63.6(3)&nbsp;h | β^− | ¹⁷²Yb | 2− | |-id=Thulium-172m | style="text-indent:1em" | ^172mTm | colspan="3" style="text-indent:2em" | 476.2(2)&nbsp;keV | 132(7)&nbsp;μs | IT | ¹⁷²Tm | (6+) | |-id=Thulium-173 | ¹⁷³Tm | style="text-align:right" | 69 | style="text-align:right" | 104 | 172.9396066(47) | 8.24(8)&nbsp;h | β^− | ¹⁷³Yb | (1/2+) | |-id=Thulium-173m1 | style="text-indent:1em" | ^173m1Tm | colspan="3" style="text-indent:2em" | 317.73(20)&nbsp;keV | 10.7(17)&nbsp;μs | IT | ¹⁷³Tm | 7/2− | |-id=Thulium-173m2 | style="text-indent:1em" | ^173m2Tm | colspan="3" style="text-indent:2em" | 1905.7(4)&nbsp;keV | 250(69)&nbsp;ns | IT | ¹⁷³Tm | 19/2− | |-id=Thulium-173m3 | style="text-indent:1em" | ^173m3Tm | colspan="3" style="text-indent:2em" | 4047.9(5)&nbsp;keV | 121(28)&nbsp;ns | IT | ¹⁷³Tm | 35/2− | |-id=Thulium-174 | ¹⁷⁴Tm | style="text-align:right" | 69 | style="text-align:right" | 105 | 173.942174(48) | 5.4(1)&nbsp;min | β^− | ¹⁷⁴Yb | 4− | |-id=Thulium-174m1 | rowspan=2 style="text-indent:1em" | ^174m1Tm | rowspan=2 colspan="3" style="text-indent:2em" | 252.4(7)&nbsp;keV | rowspan=2|2.29(1)&nbsp;s | IT (>98.5%) | ¹⁷⁴Tm | rowspan=2|0+ | rowspan=2| |- | β^− (<1.5%) | ¹⁷⁴Yb |-id=Thulium-174m2 | style="text-indent:1em" | ^174m2Tm | colspan="3" style="text-indent:2em" | 2091.7(3)&nbsp;keV | 106(7)&nbsp;μs | IT | ¹⁷⁴Tm | 14− | |-id=Thulium-175 | ¹⁷⁵Tm | style="text-align:right" | 69 | style="text-align:right" | 106 | 174.943842(54) | 15.2(5)&nbsp;min | β^− | ¹⁷⁵Yb | (1/2)+ | |-id=Thulium-175m1 | style="text-indent:1em" | ^175m1Tm | colspan="3" style="text-indent:2em" | 440.0(11)&nbsp;keV | 319(35)&nbsp;ns | IT | ¹⁷⁵Tm | 7/2− | |-id=Thulium-175m2 | style="text-indent:1em" | ^175m2Tm | colspan="3" style="text-indent:2em" | 1517.7(12)&nbsp;keV | 21(14)&nbsp;μs | IT | ¹⁷⁵Tm | 23/2+ | |-id=Thulium-176 | ¹⁷⁶Tm | style="text-align:right" | 69 | style="text-align:right" | 107 | 175.94700(11) | 1.85(3)&nbsp;min | β^− | ¹⁷⁶Yb | (4+) | |-id=Thulium-177 | ¹⁷⁷Tm | style="text-align:right" | 69 | style="text-align:right" | 108 | 176.94893(22)# | 95(7)&nbsp;s | β^− | ¹⁷⁷Yb | 1/2+# | |-id=Thulium-177m | style="text-indent:1em" | ^177mTm | colspan="3" style="text-indent:2em" | 100(100)#&nbsp;keV | 77(11)&nbsp;s | β^− | ¹⁷⁷Yb | 7/2−# | |-id=Thulium-178 | ¹⁷⁸Tm | style="text-align:right" | 69 | style="text-align:right" | 109 | 177.95251(32)# | 10#&nbsp;s<br />[>300&nbsp;ns] | | | 1−# | |-id=Thulium-179 | ¹⁷⁹Tm | style="text-align:right" | 69 | style="text-align:right" | 110 | 178.95502(43)# | 18#&nbsp;s<br />[>300&nbsp;ns] | | | 1/2+# | |-id=Thulium-180 | ¹⁸⁰Tm | style="text-align:right" | 69 | style="text-align:right" | 111 | 179.95902(43)# | 3#&nbsp;s<br />[>300&nbsp;ns] | | | | |-id=Thulium-181 | ¹⁸¹Tm | style="text-align:right" | 69 | style="text-align:right" | 112 | 180.96195(54)# | 7#&nbsp;s<br />[>300&nbsp;ns] | | | 1/2+# | |-id=Thulium-182 | ¹⁸²Tm | style="text-align:right" | 69 | style="text-align:right" | 113 | 181.96619(54)# | | | | | |-id=Thulium-183 | ¹⁸³Tm | style="text-align:right" | 69 | style="text-align:right" | 114 | | | | | |

Thulium-170

Thulium-170 has a half-life of 128.6 days, decaying by β^− decay about 99.87% of the time and electron capture the remaining 0.13% of the time. Due to its low-energy X-ray emissions, it has been proposed for radiotherapy and as a source in a radiothermal generator.

See also

Daughter products other than thulium

• Isotopes of ytterbium
• Isotopes of erbium
• Isotopes of holmium

References