Isotopes of erbium

Naturally occurring erbium (₆₈Er) is composed of six stable isotopes, with ¹⁶⁶Er being the most abundant (33.503% natural abundance). Radioisotopes have been characterized with from ¹⁴⁵Er to ¹⁷⁵Er, all having half-lives less than ten days: the most stable are ¹⁶⁹Er (9.39 days), ¹⁷²Er (49.3 hours), and ¹⁶⁰Er (28.58 hours). All of the remaining radioactive isotopes have half-lives that are less than 11 hours, and the majority of these have half-lives that are less than 4 minutes. This element also has numerous meta states, with the most stable being ^149m1Er (t_1/2 = 8.9 seconds).

The primary decay mode before the most abundant stable isotope, ¹⁶⁶Er, is electron capture to holmium isotopes, and the primary mode after is beta decay to thulium isotopes. All isotopes of erbium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.

List of isotopes

|-id=Erbium-142 | ¹⁴²Er | style="text-align:right" | 68 | style="text-align:right" | 74 | 141.97002(54)# | 10#&nbsp;μs<br>[>310&nbsp;ns] | | | 0+ | | |-id=Erbium-143 | ¹⁴³Er | style="text-align:right" | 68 | style="text-align:right" | 75 | 142.96655(43)# | 200#&nbsp;ms | | | 9/2−# | | |-id=Erbium-144 | ¹⁴⁴Er | style="text-align:right" | 68 | style="text-align:right" | 76 | 143.96070(21)# | 400#&nbsp;ms[>&nbsp;200&nbsp;ns] | | | 0+ | | |-id=Erbium-145 | rowspan=2| ¹⁴⁵Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 77 | rowspan=2| 144.95787(22)# | rowspan=2| 900(200)&nbsp;ms | β⁺ | ¹⁴⁵Ho | rowspan=2|1/2+# | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹⁴⁴Dy |-id=Erbium-145m | rowspan=2 style="text-indent:1em" | ^145mEr | rowspan=2 colspan="3" style="text-indent:2em" | 205(4)#&nbsp;keV | rowspan=2| 1.0(3)&nbsp;s | β⁺ | ¹⁴⁵Ho | rowspan=2| (11/2-) | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹⁴⁴Dy |-id=Erbium-146 | rowspan=2|¹⁴⁶Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 78 | rowspan=2|145.952418(7) | rowspan=2|1.7(6)&nbsp;s | β⁺ | ¹⁴⁶Ho | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹⁴⁵Dy |-id=Erbium-147 | rowspan=2|¹⁴⁷Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 79 | rowspan=2|146.94996(4)# | rowspan=2|3.2(12)&nbsp;s | β⁺ | ¹⁴⁷Ho | rowspan=2|(1/2+) | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹⁴⁶Dy |-id=Erbium-147m | rowspan=2 style="text-indent:1em" | ^147mEr | rowspan=2 colspan="3" style="text-indent:2em" | 100(50)#&nbsp;keV | rowspan=2| 1.6(2)&nbsp;s | β⁺ | ¹⁴⁷Ho | rowspan=2| (11/2−) | rowspan=2| | rowspan=2| |- | β⁺, p (?%) | ¹⁴⁶Dy |-id=Erbium-148 | rowspan=2|¹⁴⁸Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 80 | rowspan=2|147.944735(11)# | rowspan=2|4.6(2)&nbsp;s | β⁺ (99.85%) | ¹⁴⁸Ho | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺, p (0.15%) | ¹⁴⁷Dy |-id=Erbium-148m | style="text-indent:1em" | ^148mEr | colspan="3" style="text-indent:2em" | 2.9132(4)&nbsp;MeV | 13(3)&nbsp;μs | IT | ¹⁴⁸Er | (10+) | | |-id=Erbium-149 | rowspan=2|¹⁴⁹Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 81 | rowspan=2|148.94231(3) | rowspan=2|4(2)&nbsp;s | β⁺ (93%) | ¹⁴⁹Ho | rowspan=2|(1/2+) | rowspan=2| | rowspan=2| |- | β⁺, p (7%) | ¹⁴⁸Dy |-id=Erbium-149m1 | rowspan=3 style="text-indent:1em" | ^149m1Er | rowspan=3 colspan="3" style="text-indent:2em" | 741.8(2)&nbsp;keV | rowspan=3|8.9(2)&nbsp;s | β⁺ (96.3%) | ¹⁴⁹Ho | rowspan=3|(11/2−) | rowspan=3| | rowspan=3| |- | IT (3.5%) | ¹⁴⁹Er |- | β⁺, p (0.18%) | ¹⁴⁸Dy |-id=Erbium-149m2 | style="text-indent:1em" | ^149m2Er | colspan="3" style="text-indent:2em" | 2.6111(3)&nbsp;MeV | 0.61(8)&nbsp;μs | IT | ¹⁴⁹Er | (19/2+) | | |-id=Erbium-149m3 | style="text-indent:1em" | ^149m3Er | colspan="3" style="text-indent:2em" | 3.302(7)&nbsp;MeV | 4.8(1)&nbsp;μs | IT | ¹⁴⁹Er | (27/2−) | | |-id=Erbium-150 | ¹⁵⁰Er | style="text-align:right" | 68 | style="text-align:right" | 82 | 149.937916(18) | 18.5(7)&nbsp;s | β⁺ | ¹⁵⁰Ho | 0+ | | |-id=Erbium-150m | style="text-indent:1em" | ^150mEr | colspan="3" style="text-indent:2em" | 2.7965(5)&nbsp;MeV | 2.55(10)&nbsp;μs | IT | ¹⁵⁰Er | 10+ | | |-id=Erbium-151 | ¹⁵¹Er | style="text-align:right" | 68 | style="text-align:right" | 83 | 150.937449(18) | 23.5(20)&nbsp;s | β⁺ | ¹⁵¹Ho | (7/2−) | | |-id=Erbium-151m1 | rowspan=2 style="text-indent:1em" | ^151m1Er | rowspan=2 colspan="3" style="text-indent:2em" | 2.5860(5)&nbsp;MeV | rowspan=2|580(20)&nbsp;ms | IT (95.3%) | ¹⁵¹Er | rowspan=2|(27/2−) | rowspan=2| | rowspan=2| |- | β⁺ (4.7%) | ¹⁵¹Ho |-id=Erbium-151m2 | style="text-indent:1em" | ^151m2Er | colspan="3" style="text-indent:2em" | 10.2866(10)&nbsp;MeV | 0.42(5)&nbsp;μs | IT | ¹⁵¹Er | (65/2-, 61/2+) | | |-id=Erbium-152 | rowspan=2|¹⁵²Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 84 | rowspan=2|151.935050(9) | rowspan=2|10.3(1)&nbsp;s | α (90%) | ¹⁴⁸Dy | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺ (10%) | ¹⁵²Ho |-id=Erbium-153 | rowspan=2|¹⁵³Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 85 | rowspan=2|152.935086(10) | rowspan=2|37.1(2)&nbsp;s | α (53%) | ¹⁴⁹Dy | rowspan=2|7/2− | rowspan=2| | rowspan=2| |- | β⁺ (47%) | ¹⁵³Ho |-id=Erbium-153m1 | style="text-indent:1em" | ^153m1Er | colspan="3" style="text-indent:2em" | 2.7982(10)&nbsp;MeV | 373(9)&nbsp;ns | IT | ¹⁵³Er | (27/2-) | | |-id=Erbium-153m2 | style="text-indent:1em" | ^153m2Er | colspan="3" style="text-indent:2em" | 5.2481(10)&nbsp;MeV | 248(32)&nbsp;ns | IT | ¹⁵³Er | (41/2-) | | |-id=Erbium-154 | rowspan=2|¹⁵⁴Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 86 | rowspan=2|153.932791(5) | rowspan=2|3.73(9)&nbsp;min | β⁺ (99.53%) | ¹⁵⁴Ho | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | α (0.47%) | ¹⁵⁰Dy |-id=Erbium-155 | rowspan=2|¹⁵⁵Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 87 | rowspan=2|154.933216(7) | rowspan=2|5.3(3)&nbsp;min | β⁺ (99.978%) | ¹⁵⁵Ho | rowspan=2|7/2− | rowspan=2| | rowspan=2| |- | α (0.022%) | ¹⁵¹Dy |-id=Erbium-156 | rowspan=2| ¹⁵⁶Er | rowspan=2 style="text-align:right" | 68 | rowspan=2 style="text-align:right" | 88 | rowspan=2| 155.931066(26) | rowspan=2| 19.5(10)&nbsp;min | β⁺ | ¹⁵⁶Ho | rowspan=2| 0+ | rowspan=2| | rowspan=2| |- | α (1.2%) | ¹⁵²Dy |-id=Erbium-157 | ¹⁵⁷Er | style="text-align:right" | 68 | style="text-align:right" | 89 | 156.931923(28) | 18.65(10)&nbsp;min | β⁺ | ¹⁵⁷Ho | 3/2− | | |-id=Erbium-157m | style="text-indent:1em" | ^157mEr | colspan="3" style="text-indent:2em" | 155.4(3)&nbsp;keV | 76(6)&nbsp;ms | IT | ¹⁵⁷Er | 9/2+ | | |-id=Erbium-158 | ¹⁵⁸Er | style="text-align:right" | 68 | style="text-align:right" | 90 | 157.929893(27) | 2.29(6)&nbsp;h | EC | ¹⁵⁸Ho | 0+ | | |-id=Erbium-159 | ¹⁵⁹Er | style="text-align:right" | 68 | style="text-align:right" | 91 | 158.930691(4) | 36(1)&nbsp;min | β⁺ | ¹⁵⁹Ho | 3/2− | | |-id=Erbium-159m1 | style="text-indent:1em" | ^159m1Er | colspan="3" style="text-indent:2em" | 182.602(24)&nbsp;keV | 337(14)&nbsp;ns | IT | ¹⁵⁹Er | 9/2+ | | |-id=Erbium-159m2 | style="text-indent:1em" | ^159m2Er | colspan="3" style="text-indent:2em" | 429.05(3)&nbsp;keV | 590(60)&nbsp;ns | IT | ¹⁵⁹Er | 11/2− | | |-id=Erbium-160 | ¹⁶⁰Er | style="text-align:right" | 68 | style="text-align:right" | 92 | 159.929077(26) | 28.58(9)&nbsp;h | EC | ¹⁶⁰Ho | 0+ | | |-id=Erbium-161 | ¹⁶¹Er | style="text-align:right" | 68 | style="text-align:right" | 93 | 160.930004(9) | 3.21(3)&nbsp;h | β⁺ | ¹⁶¹Ho | 3/2− | | |-id=Erbium-161m | style="text-indent:1em" | ^161mEr | colspan="3" style="text-indent:2em" | 396.44(4)&nbsp;keV | 7.5(7)&nbsp;μs | IT | ¹⁶¹Er | 11/2− | | |-id=Erbium-162 | ¹⁶²Er | style="text-align:right" | 68 | style="text-align:right" | 94 | 161.9287873(8) | colspan=3 align=center|Observationally Stable | 0+ | 0.00139(5) | |-id=Erbium-162m | style="text-indent:1em" | ^162mEr | colspan="3" style="text-indent:2em" | 2.02601(13)&nbsp;MeV | 88(16)&nbsp;ns | IT | ¹⁶²Er | 7(-) | | |-id=Erbium-163 | ¹⁶³Er | style="text-align:right" | 68 | style="text-align:right" | 95 | 162.930040(5) | 75.0(4)&nbsp;min | β⁺ | ¹⁶³Ho | 5/2− | | |-id=Erbium-163m | style="text-indent:1em" | ^163mEr | colspan="3" style="text-indent:2em" | 445.5(6)&nbsp;keV | 580(100)&nbsp;ns | IT | ¹⁶³Er | (11/2−) | | |-id=Erbium-164 | ¹⁶⁴Er | style="text-align:right" | 68 | style="text-align:right" | 96 | 163.9292077(8) | colspan=3 align=center|Observationally Stable | 0+ | 0.01601(3) | |-id=Erbium-165 | ¹⁶⁵Er | style="text-align:right" | 68 | style="text-align:right" | 97 | 164.9307335(10) | 10.36(4)&nbsp;h | EC | ¹⁶⁵Ho | 5/2− | | |-id=Erbium-165m1 | style="text-indent:1em" | ^165m1Er | colspan="3" style="text-indent:2em" | 551.3(6)&nbsp;keV | 250(30)&nbsp;ns | IT | ¹⁶⁵Er | 11/2- | | |-id=Erbium-165m2 | style="text-indent:1em" | ^165m2Er | colspan="3" style="text-indent:2em" | 1.8230(6)&nbsp;MeV | 370(40)&nbsp;ns | IT | ¹⁶⁵Er | (19/2) | | |-id=Erbium-166 | ¹⁶⁶Er | style="text-align:right" | 68 | style="text-align:right" | 98 | 165.9303011(4) | colspan=3 align=center|Observationally Stable | 0+ | 0.33503(36) | |-id=Erbium-167 | ¹⁶⁷Er | style="text-align:right" | 68 | style="text-align:right" | 99 | 166.9320562(3) | colspan=3 align=center|Observationally Stable | 7/2+ | 0.22869(9) | |-id=Erbium-167m | style="text-indent:1em" | ^167mEr | colspan="3" style="text-indent:2em" | 207.801(5)&nbsp;keV | 2.269(6)&nbsp;s | IT | ¹⁶⁷Er | 1/2− | | |-id=Erbium-168 | ¹⁶⁸Er | style="text-align:right" | 68 | style="text-align:right" | 100 | 167.93237828(28) | colspan=3 align=center|Observationally Stable | 0+ | 0.26978(18) | |-id=Erbium-168m | style="text-indent:1em" | ^168mEr | colspan="3" style="text-indent:2em" | 1.0940383(16)&nbsp;MeV | 109.0(7)&nbsp;ns | IT | ¹⁶⁸Er | 4- | | |-id=Erbium-169 | ¹⁶⁹Er | style="text-align:right" | 68 | style="text-align:right" | 101 | 168.9345984(3) | 9.392(18)&nbsp;d | β^− | ¹⁶⁹Tm | 1/2− | | |-id=Erbium-169m1 | style="text-indent:1em" | ^169m1Er | colspan="3" style="text-indent:2em" | 92.05(10)&nbsp;keV | 285(20)&nbsp;ns | IT | ¹⁶⁹Er | (5/2)- | | |-id=Erbium-169m2 | style="text-indent:1em" | ^169m2Er | colspan="3" style="text-indent:2em" | 243.69(17)&nbsp;keV | 200(10)&nbsp;ns | IT | ¹⁶⁹Er | 7/2+ | | |-id=Erbium-170 | ¹⁷⁰Er | style="text-align:right" | 68 | style="text-align:right" | 102 | 169.9354719(15) | colspan=3 align=center|Observationally Stable | 0+ | 0.14910(36) | |-id=Erbium-171 | ¹⁷¹Er | style="text-align:right" | 68 | style="text-align:right" | 103 | 170.9380374(15) | 7.516(2)&nbsp;h | β^− | ¹⁷¹Tm | 5/2− | | |-id=Erbium-171m | style="text-indent:1em" | ^171mEr | colspan="3" style="text-indent:2em" | 198.61(9)&nbsp;keV | 210(10)&nbsp;ns | IT | ¹⁷¹Er | 1/2− | | |-id=Erbium-172 | ¹⁷²Er | style="text-align:right" | 68 | style="text-align:right" | 104 | 171.939363(4) | 49.3(5)&nbsp;h | β^− | ¹⁷²Tm | 0+ | | |- |-id=Erbium-172m | style="text-indent:1em" | ^172mEr | colspan="3" style="text-indent:2em" | 1.5009(3)&nbsp;MeV | 579(62)&nbsp;ns | IT | ¹⁷²Er | (6+) | | |-id=Erbium-173 | ¹⁷³Er | style="text-align:right" | 68 | style="text-align:right" | 105 | 172.94240(21)# | 1.434(17)&nbsp;min | β^− | ¹⁷³Tm | (7/2−) | | |-id=Erbium-174 | ¹⁷⁴Er | style="text-align:right" | 68 | style="text-align:right" | 106 | 173.94423(32)# | 3.2(2)&nbsp;min | β^− | ¹⁷⁴Tm | 0+ | | |-id=Erbium-174m | style="text-indent:1em" | ^174mEr | colspan="3" style="text-indent:2em" | 1.1115(7)&nbsp;MeV | 3.9(3)&nbsp;s | IT | ¹⁷⁴Er | 8- | | |-id=Erbium-175 | ¹⁷⁵Er | style="text-align:right" | 68 | style="text-align:right" | 107 | 174.94777(43)# | 1.2(3)&nbsp;min | β^− | ¹⁷⁵Tm | 9/2+# | | |-id=Erbium-176 | ¹⁷⁶Er | style="text-align:right" | 68 | style="text-align:right" | 108 | 175.94994(43)# | 12#&nbsp;s[>300&nbsp;ns] | | | 0+ | | |-id=Erbium-177 | ¹⁷⁷Er | style="text-align:right" | 68 | style="text-align:right" | 109 | 176.95399(54)# | 8#&nbsp;s[>300&nbsp;ns] | | | 1/2−# | | |-id=Erbium-178 | ¹⁷⁸Er | style="text-align:right" | 68 | style="text-align:right" | 110 | 177.95678(64)# | 4#&nbsp;s[>300&nbsp;ns] | | | 0+ | | |-id=Erbium-179 | ¹⁷⁹Er | style="text-align:right" | 68 | style="text-align:right" | 111 | 178.96127(54)# | 3#&nbsp;s[>550&nbsp;ns)] | | | 3/2−# | | |-id=Erbium-180 | ¹⁸⁰Er | style="text-align:right" | 68 | style="text-align:right" | 112 | 179.96438(54)# | 2#&nbsp;s[>550&nbsp;ns] | | | 0+ | |

See also

Daughter products other than erbium

• Isotopes of thulium
• Isotopes of holmium
• Isotopes of dysprosium

References

• Isotope masses from:
• Isotopic compositions and standard atomic masses from:
• Half-life, spin, and isomer data selected from the following sources.