Naturally occurring

erbium Erbium is a chemical element; it has Symbol (chemistry), symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare- ...

(₆₈Er) is composed of six stable

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

s, with ¹⁶⁶Er being the most abundant (33.503%

natural abundance In physics, natural abundance (NA) refers to the abundance of isotopes of a chemical element as naturally found on a planet. The relative atomic mass (a weighted average, weighted by mole-fraction abundance figures) of these isotopes is the ato ...

). Thirty-nine

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ...

s have been characterized with between 74 and 112 neutrons, or 142 to 180 nucleons, with the most stable being ¹⁶⁹Er with a

half-life Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * ''Half Life: ...

of 9.4 days, ¹⁷²Er with a half-life of 49.3 hours, ¹⁶⁰Er with a half-life of 28.58 hours, ¹⁶⁵Er with a half-life of 10.36 hours, and ¹⁷¹Er with a half-life of 7.516 hours. All of the remaining

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...

isotopes have half-lives that are less than 3.5 hours, and the majority of these have half-lives that are less than 4 minutes. This element also has numerous

meta state A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy excited state levels (higher energy levels). "Metastable" describes nuclei whose excited states have half-lives of 10−9 s ...

s, with the most stable being ^167mEr (t_1/2 = 2.269 seconds). The isotopes of erbium range in

atomic weight Relative atomic mass (symbol: ''A''; sometimes abbreviated RAM or r.a.m.), also known by the deprecated synonym atomic weight, is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a giv ...

from 141.9723 u (¹⁴²Er) to 179.9644 u (¹⁸⁰Er). The primary

decay mode Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...

before the most abundant stable isotope, ¹⁶⁶Er, is

electron capture Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Th ...

, and the primary mode after is

beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which an atomic nucleus emits a beta particle (fast energetic electron or positron), transforming into an isobar of that nuclide. For example, beta decay of a neutron ...

. The primary

decay product In nuclear physics, a decay product (also known as a daughter product, daughter isotope, radio-daughter, or daughter nuclide) is the remaining nuclide left over from radioactive decay. Radioactive decay often proceeds via a sequence of steps ( d ...

s before ¹⁶⁶Er are

holmium Holmium is a chemical element; it has symbol Ho and atomic number 67. It is a rare-earth element and the eleventh member of the lanthanide series. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like many other ...

isotopes, and the primary products after are

thulium Thulium is a chemical element; it has symbol Tm and atomic number 69. It is the thirteenth element in the lanthanide series of metals. It is the second-least abundant lanthanide in the Earth's crust, after radioactively unstable promethium. It i ...

isotopes. All isotopes of erbium are either radioactive or

observationally stable Stable nuclides are isotopes of a chemical element whose nucleons are in a configuration that does not permit them the surplus energy required to produce a radioactive emission. The nuclei of such isotopes are not radioactive and unlike radionuc ...

, meaning that they are predicted to be radioactive but no actual decay has been observed.

List of isotopes

, -id=Erbium-143 , ¹⁴³Er , style="text-align:right" , 68 , style="text-align:right" , 75 , 142.96655(43)# , 200# ms , , , 9/2−# , , , -id=Erbium-144 , ¹⁴⁴Er , style="text-align:right" , 68 , style="text-align:right" , 76 , 143.96070(21)# , 400# ms
200 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) 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)# keV , rowspan=2, 1.0(3) 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) 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) s , β⁺ , ¹⁴⁷Ho , rowspan=2, (1/2+) , rowspan=2, , rowspan=2, , - , β⁺, p (?%) , ¹⁴⁶Dy , -id=Erbium-147m , rowspan=2 style="text-indent:1em" , ^147mErOrder of ground state and isomer is uncertain. , rowspan=2 colspan="3" style="text-indent:2em" , 100(50)# keV , rowspan=2, 1.6(2) 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) 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) MeV , 13(3) 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) 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) keV , rowspan=3, 8.9(2) 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) MeV , 0.61(8) μs , IT , ¹⁴⁹Er , (19/2+) , , , -id=Erbium-149m3 , style="text-indent:1em" , ^149m3Er , colspan="3" style="text-indent:2em" , 3.302(7) MeV , 4.8(1) 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) s , β⁺ , ¹⁵⁰Ho , 0+ , , , -id=Erbium-150m , style="text-indent:1em" , ^150mEr , colspan="3" style="text-indent:2em" , 2.7965(5) MeV , 2.55(10) μs , IT , ¹⁵⁰Er , 10+ , , , -id=Erbium-151 , ¹⁵¹Er , style="text-align:right" , 68 , style="text-align:right" , 83 , 150.937449(18) , 23.5(20) 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) MeV , rowspan=2, 580(20) 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) MeV , 0.42(5) 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) 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) 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) MeV , 373(9) ns , IT , ¹⁵³Er , (27/2-) , , , -id=Erbium-153m2 , style="text-indent:1em" , ^153m2Er , colspan="3" style="text-indent:2em" , 5.2481(10) MeV , 248(32) 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) 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) 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) 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) min , β⁺ , ¹⁵⁷Ho , 3/2− , , , -id=Erbium-157m , style="text-indent:1em" , ^157mEr , colspan="3" style="text-indent:2em" , 155.4(3) keV , 76(6) 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) h , EC , ¹⁵⁸Ho , 0+ , , , -id=Erbium-159 , ¹⁵⁹Er , style="text-align:right" , 68 , style="text-align:right" , 91 , 158.930691(4) , 36(1) min , β⁺ , ¹⁵⁹Ho , 3/2− , , , -id=Erbium-159m1 , style="text-indent:1em" , ^159m1Er , colspan="3" style="text-indent:2em" , 182.602(24) keV , 337(14) ns , IT , ¹⁵⁹Er , 9/2+ , , , -id=Erbium-159m2 , style="text-indent:1em" , ^159m2Er , colspan="3" style="text-indent:2em" , 429.05(3) keV , 590(60) 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) h , EC , ¹⁶⁰Ho , 0+ , , , -id=Erbium-161 , ¹⁶¹Er , style="text-align:right" , 68 , style="text-align:right" , 93 , 160.930004(9) , 3.21(3) h , β⁺ , ¹⁶¹Ho , 3/2− , , , -id=Erbium-161m , style="text-indent:1em" , ^161mEr , colspan="3" style="text-indent:2em" , 396.44(4) keV , 7.5(7) 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 Stable nuclides are isotopes of a chemical element whose nucleons are in a configuration that does not permit them the surplus energy required to produce a radioactive emission. The nuclei of such isotopes are not radioactive and unlike radionuc ...

Believed to undergo α decay to ¹⁵⁸Dy or β⁺β⁺ to ¹⁶²Dy with a

over 1.40 years , 0+ , 0.00139(5) , , -id=Erbium-162m , style="text-indent:1em" , ^162mEr , colspan="3" style="text-indent:2em" , 2.02601(13) MeV , 88(16) ns , IT , ¹⁶²Er , 7(-) , , , -id=Erbium-163 , ¹⁶³Er , style="text-align:right" , 68 , style="text-align:right" , 95 , 162.930040(5) , 75.0(4) min , β⁺ , ¹⁶³Ho , 5/2− , , , -id=Erbium-163m , style="text-indent:1em" , ^163mEr , colspan="3" style="text-indent:2em" , 445.5(6) keV , 580(100) 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 StableBelieved to undergo α decay to ¹⁶⁰Dy or β⁺β⁺ to ¹⁶⁴Dy , 0+ , 0.01601(3) , , -id=Erbium-165 , ¹⁶⁵Er , style="text-align:right" , 68 , style="text-align:right" , 97 , 164.9307335(10) , 10.36(4) h , EC , ¹⁶⁵Ho , 5/2− , , , -id=Erbium-165m1 , style="text-indent:1em" , ^165m1Er , colspan="3" style="text-indent:2em" , 551.3(6) keV , 250(30) ns , IT , ¹⁶⁵Er , 11/2- , , , -id=Erbium-165m2 , style="text-indent:1em" , ^165m2Er , colspan="3" style="text-indent:2em" , 1.8230(6) MeV , 370(40) 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 StableBelieved to undergo α decay to ¹⁶²Dy , 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 StableBelieved to undergo α decay to ¹⁶³Dy , 7/2+ , 0.22869(9) , , -id=Erbium-167m , style="text-indent:1em" , ^167mEr , colspan="3" style="text-indent:2em" , 207.801(5) keV , 2.269(6) 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 StableBelieved to undergo α decay to ¹⁶⁴Dy , 0+ , 0.26978(18) , , -id=Erbium-168m , style="text-indent:1em" , ^168mEr , colspan="3" style="text-indent:2em" , 1.0940383(16) MeV , 109.0(7) ns , IT , ¹⁶⁸Er , 4- , , , -id=Erbium-169 , ¹⁶⁹Er , style="text-align:right" , 68 , style="text-align:right" , 101 , 168.9345984(3) , 9.392(18) d , β⁻ , ¹⁶⁹Tm , 1/2− , , , -id=Erbium-169m1 , style="text-indent:1em" , ^169m1Er , colspan="3" style="text-indent:2em" , 92.05(10) keV , 285(20) ns , IT , ¹⁶⁹Er , (5/2)- , , , -id=Erbium-169m2 , style="text-indent:1em" , ^169m2Er , colspan="3" style="text-indent:2em" , 243.69(17) keV , 200(10) 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 StableBelieved to undergo α decay to ¹⁶⁶Dy or β⁻β⁻ to ¹⁷⁰Yb with a half-life over 4.10 years , 0+ , 0.14910(36) , , -id=Erbium-171 , ¹⁷¹Er , style="text-align:right" , 68 , style="text-align:right" , 103 , 170.93803746(15) , 7.516(2) h , β⁻ , ¹⁷¹Tm , 5/2− , , , -id=Erbium-171m , style="text-indent:1em" , ^171mEr , colspan="3" style="text-indent:2em" , 198.61(9) keV , 210(10) 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) h , β⁻ , ¹⁷²Tm , 0+ , , , - , -id=Erbium-172m , style="text-indent:1em" , ^172mEr , colspan="3" style="text-indent:2em" , 1.5009(3) MeV , 579(62) ns , IT , ¹⁷²Er , (6+) , , , -id=Erbium-173 , ¹⁷³Er , style="text-align:right" , 68 , style="text-align:right" , 105 , 172.94240(21)# , 1.434(17) 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) min , β⁻ , ¹⁷⁴Tm , 0+ , , , -id=Erbium-174m , style="text-indent:1em" , ^174mEr , colspan="3" style="text-indent:2em" , 1.1115(7) MeV , 3.9(3) s , IT , ¹⁷⁴Er , 8- , , , -id=Erbium-175 , ¹⁷⁵Er , style="text-align:right" , 68 , style="text-align:right" , 107 , 174.94777(43)# , 1.2(3) min , β⁻ , ¹⁷⁵Tm , 9/2+# , , , -id=Erbium-176 , ¹⁷⁶Er , style="text-align:right" , 68 , style="text-align:right" , 108 , 175.94994(43)# , 12# s
300 ns, , , 0+ , , , -id=Erbium-177 , ¹⁷⁷Er , style="text-align:right" , 68 , style="text-align:right" , 109 , 176.95399(54)# , 8# s
300 ns, , , 1/2−# , , , -id=Erbium-178 , ¹⁷⁸Er , style="text-align:right" , 68 , style="text-align:right" , 110 , 177.95678(64)# , 4# s
300 ns, , , 0+ , , , -id=Erbium-179 , ¹⁷⁹Er , style="text-align:right" , 68 , style="text-align:right" , 111 , 178.96127(54)# , 3# s
550 ns), , , 3/2−# , , , -id=Erbium-180 , ¹⁸⁰Er , style="text-align:right" , 68 , style="text-align:right" , 112 , 179.96438(54)# , 2# s
550 ns, , , 0+ , ,

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Erbium

Erbium Erbium is a chemical element; it has Symbol (chemistry), symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare- ...

List of isotopes

See also

References