Isotopes of gadolinium

{{Short description|none}} {{Infobox gadolinium isotopes}} thumb | right | Gadolinium Naturally occurring gadolinium (₆₄Gd) is composed of six stable isotopes, ¹⁵⁴Gd, ¹⁵⁵Gd, ¹⁵⁶Gd, ¹⁵⁷Gd, ¹⁵⁸Gd and ¹⁶⁰Gd, and one long-lived radioisotope, ¹⁵²Gd, with ¹⁵⁸Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of ¹⁶⁰Gd has not been observed.

In all, 32 radioisotopes of gadolinium have been characterized, with the three most stable being alpha emitters: ¹⁵²Gd (naturally occurring) with a half-life of 1.08×10¹⁴ years, ¹⁵⁰Gd with a half-life of 1.79×10⁶ years, and ¹⁴⁸Gd (theoretically not beta-stable) with a half-life of 86.9 years. All of the remaining radioactive isotopes have half-lives less than a year, the majority of these having half-lives less than two minutes. There are also 16 metastable isomers, with the most stable being ^143mGd (t_1/2 = 110 seconds), ^145mGd (t_1/2 = 85 seconds) and ^141mGd (t_1/2 = 24.5 seconds).

The isotopes with atomic masses lower than the most abundant stable isotope, ¹⁵⁸Gd, primarily decay by electron capture to isotopes of europium. For higher atomic masses, the primary decay mode is beta decay to isotopes of terbium.

== List of isotopes == {{Anchor}}

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{{Isotopes table |symbol=Gd |refs=NUBASE2020, AME2020 II, IsotopeFRIB, IsomerFRIB |notes=m, unc(), mass#, exen#, hl#, hl-nst, spin(), spin#, daughter-st, daughter-nst, EC, IT, discoveryname }} |-id=Gadolinium-133 | ¹³³Gd<ref name="suzuki2026">{{cite journal |last1=Suzuki |first1=H |last2=Fukuda |first2=N |last3=Takeda |first3=H |last4=Shimizu |first4=Y |last5=Yoshimoto |first5=M |last6=Togano |first6=Y |last7=Sato |first7=H |last8=Kitamura |first8=N |last9=Momota |first9=S |last10=Kusaka |first10=K |last11=Yanagisawa |first11=Y |last12=Ohtake |first12=M |last13=Fukunishi |first13=N |last14=Michimasa |first14=S |title=Discovery of Proton-Rich Radioactive Isotopes in the Z = 63–70 Region Produced by the Projectile Fragmentation of a 345-MeV/Nucleon 238U Beam |journal=Progress of Theoretical and Experimental Physics |date=3 February 2026 |volume=2026 |issue=2 |doi=10.1093/ptep/ptaf190|doi-access=free }}</ref> | style="text-align:right" | 64 | style="text-align:right" | 69 | 132.96129(54)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/133.pdf 2026] | 10#&nbsp;ms<br>[>310&nbsp;ns] | | | 5/2+# | | |-id=Gadolinium-134 | ¹³⁴Gd<ref name="suzuki2026"/> | style="text-align:right" | 64 | style="text-align:right" | 70 | 133.95542(43)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/134.pdf 2026] | 400#&nbsp;ms<br>[>310&nbsp;ns] | | | 0+ | | |-id=Gadolinium-135 | rowspan=2|¹³⁵Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 71 | rowspan=2|134.95250(43)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/135.pdf 1996] | rowspan=2|1.1(2)&nbsp;s | β⁺ (98%) | ¹³⁵Eu | rowspan=2|(5/2+) | rowspan=2| | rowspan=2| |- | β⁺, p (98%) | ¹³⁴Sm |-id=Gadolinium-136 | rowspan=2|¹³⁶Gd<ref name="suzuki2026"/> | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 72 | rowspan=2|135.94730(32)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/136.pdf 2026] | rowspan=2|1#&nbsp;s [>310&nbsp;ns] | β⁺? | ¹³⁶Eu | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺, p? | ¹³⁵Sm |-id=Gadolinium-137 | rowspan=2|¹³⁷Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 73 | rowspan=2|136.94502(32)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/137.pdf 1999] | rowspan=2|2.2(2)&nbsp;s | β⁺ | ¹³⁷Eu | rowspan=2|(7/2)+# | rowspan=2| | rowspan=2| |- | β⁺, p? | ¹³⁶Sm |-id=Gadolinium-138 | ¹³⁸Gd | style="text-align:right" | 64 | style="text-align:right" | 74 | 137.94025(22)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/138.pdf 1985] | 4.7(9)&nbsp;s | β⁺ | ¹³⁸Eu | 0+ | | |-id=Gadolinium-138m | style="text-indent:1em" | ^138mGd | colspan="3" style="text-indent:2em" | 2232.6(11)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/138Gd-1.pdf 1997] | 6.2(0.2)&nbsp;μs | IT | ¹³⁸Gd | (8−) | | |-id=Gadolinium-139 | rowspan=2|¹³⁹Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 75 | rowspan=2|138.93813(21)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/139.pdf 1983] | rowspan=2|5.7(3)&nbsp;s | β⁺ | ¹³⁹Eu | rowspan=2|9/2−# | rowspan=2| | rowspan=2| |- | β⁺, p? | ¹³⁸Sm |-id=Gadolinium-139m | rowspan=2 style="text-indent:1em" | ^139mGd<ref group="n" name="order">Order of ground state and isomer is uncertain.</ref> | rowspan=2 colspan="3" style="text-indent:2em" | 250(150)#&nbsp;keV | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/139Gd-1.pdf 1999] | rowspan=2|4.8(9)&nbsp;s | β⁺ | ¹³⁹Eu | rowspan=2|1/2+# | rowspan=2| | rowspan=2| |- | β⁺, p? | ¹³⁸Sm |-id=Gadolinium-140 | rowspan=2|¹⁴⁰Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 76 | rowspan=2|139.933674(30) | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/140.pdf 1985] | rowspan=2|15.8(4)&nbsp;s | β⁺ (67(8)%) | rowspan=2|¹⁴⁰Eu | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | EC (33(8)%) |-id=Gadolinium-141 | rowspan=2|¹⁴¹Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 77 | rowspan=2|140.932126(21) | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/141.pdf 1986] | rowspan=2|14(4)&nbsp;s | β⁺ (99.97%) | ¹⁴¹Eu | rowspan=2|(1/2+) | rowspan=2| | rowspan=2| |- | β⁺, p (0.03%) | ¹⁴⁰Sm |-id=Gadolinium-141m | rowspan=2 style="text-indent:1em" | ^141mGd | rowspan=2 colspan="3" style="text-indent:2em" | 377.76(9)&nbsp;keV | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/141Gd-1.pdf 1989] | rowspan=2|24.5(5)&nbsp;s | β⁺ (89%) | ¹⁴¹Eu | rowspan=2|(11/2−) | rowspan=2| | rowspan=2| |- | IT (11%) | ¹⁴¹Gd |-id=Gadolinium-142 | rowspan=2|¹⁴²Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 78 | rowspan=2|141.928116(30) | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/142.pdf 1986] | rowspan=2|70.2(6)&nbsp;s | EC (52(5)%) | rowspan=2|¹⁴²Eu | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺ (48(5)%) |-id=Gadolinium-143 | rowspan=3|¹⁴³Gd | rowspan=3 style="text-align:right" | 64 | rowspan=3 style="text-align:right" | 79 | rowspan=3|142.92675(22) | rowspan=3 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/143.pdf 1975] | rowspan=3|39(2)&nbsp;s | β⁺ | ¹⁴³Eu | rowspan=3|1/2+ | rowspan=3| | rowspan=3| |- | β⁺, p? | ¹⁴²Sm |- | β⁺, α? | ¹³⁹Pm |-id=Gadolinium-143m | rowspan=3 style="text-indent:1em" | ^143mGd | rowspan=3 colspan="3" style="text-indent:2em" | 152.6(5)&nbsp;keV | rowspan=3 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/143Gd-1.pdf 1975] | rowspan=3|110.0(14)&nbsp;s | β⁺ | ¹⁴³Eu | rowspan=3|11/2− | rowspan=3| | rowspan=3| |- | β⁺, p? | ¹⁴²Sm |- | β⁺, α? | ¹³⁹Pm |-id=Gadolinium-144 | ¹⁴⁴Gd | style="text-align:right" | 64 | style="text-align:right" | 80 | 143.922963(30) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/144.pdf 1968] | 4.47(6)&nbsp;min | β⁺ | ¹⁴⁴Eu | 0+ | | |-id=Gadolinium-144m | style="text-indent:1em" | ^144mGd | colspan="3" style="text-indent:2em" | 3433.1(5)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/144Gd-1.pdf 1978] | 145(30)&nbsp;ns | IT | ¹⁴⁴Gd | (10+) | | |-id=Gadolinium-145 | ¹⁴⁵Gd | style="text-align:right" | 64 | style="text-align:right" | 81 | 144.921710(21) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/145.pdf 1959] | 23.0(4)&nbsp;min | β⁺ | ¹⁴⁵Eu | 1/2+ | | |-id=Gadolinium-145m | rowspan=2 style="text-indent:1em" | ^145mGd | rowspan=2 colspan="3" style="text-indent:2em" | 749.1(2)&nbsp;keV | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/145Gd-1.pdf 1969] | rowspan=2|85(3)&nbsp;s | IT (94.3%) | ¹⁴⁵Gd | rowspan=2|11/2− | rowspan=2| | rowspan=2| |- | β⁺ (5.7%) | ¹⁴⁵Eu |-id=Gadolinium-146 | ¹⁴⁶Gd | style="text-align:right" | 64 | style="text-align:right" | 82 | 145.9183185(44) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/146.pdf 1957] | 48.27(9)&nbsp;d | EC | ¹⁴⁶Eu | 0+ | | |-id=Gadolinium-147 | ¹⁴⁷Gd | style="text-align:right" | 64 | style="text-align:right" | 83 | 146.9191010(20) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/147.pdf 1957] | 38.06(12)&nbsp;h | β⁺ | ¹⁴⁷Eu | 7/2− | | |-id=Gadolinium-147m | style="text-indent:1em" | ^147mGd | colspan="3" style="text-indent:2em" | 8587.8(5)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/147Gd-1.pdf 1978] | 510(20)&nbsp;ns | IT | ¹⁴⁷Gd | 49/2+ | | |-id=Gadolinium-148 | ¹⁴⁸Gd | style="text-align:right" | 64 | style="text-align:right" | 84 | 147.9181214(16) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/148.pdf 1953] | 86.9(39)&nbsp;y<ref name="148Gd"/> | α<ref group="n">Theorized to also undergo β⁺β⁺ decay to '''''¹⁴⁸Sm''''' or EC to ¹⁴⁸Eu</ref> | '''¹⁴⁴Sm''' |0+ | |-id=Gadolinium-149 | rowspan=2|¹⁴⁹Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 85 | rowspan=2|148.9193477(36) | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/149.pdf 1951] | rowspan=2|9.28(10)&nbsp;d | β⁺ | ¹⁴⁹Eu | rowspan=2|7/2− | rowspan=2| | rowspan=2| |- | α (4.3×10⁻⁴%) | ¹⁴⁵Sm |-id=Gadolinium-150 |¹⁵⁰Gd |style="text-align:right" | 64 | style="text-align:right" | 86 | 149.9186639(65) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/150.pdf 1953] |1.79(8)×10⁶&nbsp;y | α<ref group="n">Theorized to also undergo β⁺β⁺ decay to '''¹⁵⁰Sm'''</ref> | ¹⁴⁶Sm |0+ | | |-id=Gadolinium-151 | rowspan=2|¹⁵¹Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 87 | rowspan=2|150.9203549(32) | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/151.pdf 1950] | rowspan=2|123.9(10)&nbsp;d | EC | '''''¹⁵¹Eu''''' | rowspan=2|7/2− | rowspan=2| | rowspan=2| |- | α (1.1×10⁻⁶%) | '''''¹⁴⁷Sm''''' |-id=Gadolinium-152 | ¹⁵²Gd<ref group="n">primordial radionuclide</ref> | style="text-align:right" | 64 | style="text-align:right" | 88 | 151.9197984(11) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/152.pdf 1938] | '''1.08(8)×10¹⁴&nbsp;y''' | α<ref group="n">Theorized to also undergo β⁺β⁺ decay to '''¹⁵²Sm'''</ref> | '''''¹⁴⁸Sm''''' | 0+ | 0.0020(1) | |-id=Gadolinium-153 | ¹⁵³Gd | style="text-align:right" | 64 | style="text-align:right" | 89 | 152.9217569(11) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/153.pdf 1947] | 240.6(7)&nbsp;d | EC | '''¹⁵³Eu''' | 3/2− | | |-id=Gadolinium-153m1 | style="text-indent:1em" | ^153m1Gd | colspan="3" style="text-indent:2em" | 95.1737(8)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/153Gd-2.pdf 1979] | 3.5(4)&nbsp;μs | IT | ¹⁵³Gd | 9/2+ | | |-id=Gadolinium-153m2 | style="text-indent:1em" | ^153m2Gd | colspan="3" style="text-indent:2em" | 171.188(4)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/153Gd-1.pdf 1967] | 76.0(14)&nbsp;μs | IT | ¹⁵³Gd | (11/2−) | | |-id=Gadolinium-154 | ¹⁵⁴Gd<ref group="n" name="FP"/> | style="text-align:right" | 64 | style="text-align:right" | 90 | 153.9208730(11) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/154.pdf 1938] | colspan="3" style="text-align:center;"|'''Observationally Stable'''<ref group="n">Believed to undergo α decay to '''¹⁵⁰Sm'''</ref> | 0+ | 0.0218(2) | |-id=Gadolinium-155 | ¹⁵⁵Gd<ref group="n" name="FP">Fission product</ref> | style="text-align:right" | 64 | style="text-align:right" | 91 | 154.9226294(11) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/155.pdf 1933] | colspan="3" style="text-align:center;"|'''Observationally Stable'''<ref group="n">Believed to undergo α decay to ¹⁵¹Sm</ref> | 3/2− | 0.1480(9) | |-id=Gadolinium-155m | style="text-indent:1em" | ^155mGd | colspan="3" style="text-indent:2em" | 121.10(19)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/155Gd-1.pdf 1967] | 31.97(27)&nbsp;ms | IT | '''¹⁵⁵Gd''' | 11/2− | | |-id=Gadolinium-156 | ¹⁵⁶Gd<ref group="n" name="FP" /> | style="text-align:right" | 64 | style="text-align:right" | 92 | 155.9221301(11) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/156.pdf 1933] | colspan="3" style="text-align:center;"|'''Stable''' | 0+ | 0.2047(3) | |-id=Gadolinium-156m | style="text-indent:1em" | ^156mGd | colspan="3" style="text-indent:2em" | 2137.60(5)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/156Gd-1.pdf 1969] | 1.3(1)&nbsp;μs | IT | '''¹⁵⁶Gd''' | 7- | | |-id=Gadolinium-157 | ¹⁵⁷Gd<ref group="n" name="FP" /> | style="text-align:right" | 64 | style="text-align:right" | 93 | 156.9239674(10) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/157.pdf 1933] | colspan="3" style="text-align:center;"|'''Stable''' | 3/2− | 0.1565(4) | |-id=Gadolinium-157m1 | style="text-indent:1em" | ^157m1Gd | colspan="3" style="text-indent:2em" | 63.916(5)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/157Gd-1.pdf 1964] | 460(40)&nbsp;ns | IT | '''¹⁵⁷Gd''' | 5/2+ | | |-id=Gadolinium-157m2 | style="text-indent:1em" | ^157m2Gd | colspan="3" style="text-indent:2em" | 426.539(23)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/157Gd-2.pdf 1967] | 18.5(23)&nbsp;μs | IT | '''¹⁵⁷Gd''' | 11/2− | | |-id=Gadolinium-158 | ¹⁵⁸Gd<ref group="n" name="FP" /> | style="text-align:right" | 64 | style="text-align:right" | 94 | 157.9241112(10) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/158.pdf 1933] | colspan="3" style="text-align:center;"|'''Stable''' | 0+ | 0.2484(8) | |-id=Gadolinium-159 | ¹⁵⁹Gd<ref group="n" name="FP" /> | style="text-align:right" | 64 | style="text-align:right" | 95 | 158.9263958(11) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/159.pdf 1949] | 18.479(4)&nbsp;h | β⁻ | '''¹⁵⁹Tb''' | 3/2− | | |-id=Gadolinium-160 | ¹⁶⁰Gd<ref group="n" name="FP" /> | style="text-align:right" | 64 | style="text-align:right" | 96 | 159.9270612(12) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/160.pdf 1933] | colspan="3" style="text-align:center;"|'''Observationally Stable'''<ref group="n">Believed to undergo β⁻β⁻ decay to '''¹⁶⁰Dy''' with a half-life over 3.1×10¹⁹ years</ref> | 0+ | 0.2186(3) | |-id=Gadolinium-161 | ¹⁶¹Gd | style="text-align:right" | 64 | style="text-align:right" | 97 | 160.9296763(16) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/161.pdf 1949] | 3.646(3)&nbsp;min | β⁻ | ¹⁶¹Tb | 5/2− | | |-id=Gadolinium-162 | ¹⁶²Gd | style="text-align:right" | 64 | style="text-align:right" | 98 | 161.9309918(43) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/162.pdf 1967] | 8.4(2)&nbsp;min | β⁻ | ¹⁶²Tb | 0+ | | |-id=Gadolinium-163 | ¹⁶³Gd | style="text-align:right" | 64 | style="text-align:right" | 99 | 162.93409664(86) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/163.pdf 1982] | 68(3)&nbsp;s | β⁻ | ¹⁶³Tb | 7/2+ | | |-id=Gadolinium-163m | rowspan=2 style="text-indent:1em" | ^163mGd | rowspan=2 colspan="3" style="text-indent:2em" | 138.22(20)&nbsp;keV | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/163Gd-1.pdf 2014] | rowspan=2|23.5(10)&nbsp;s | IT? | ¹⁶³Gd | rowspan=2|1/2− | rowspan=2| | rowspan=2| |- | β⁻ | ¹⁶³Tb |-id=Gadolinium-164 | ¹⁶⁴Gd | style="text-align:right" | 64 | style="text-align:right" | 100 | 163.9359162(11) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/164.pdf 1988] | 45(3)&nbsp;s | β⁻ | ¹⁶⁴Tb | 0+ | | |-id=Gadolinium-164m | style="text-indent:1em" | ^164mGd | colspan="3" style="text-indent:2em" | 1095.8(4)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/164Gd-1.pdf 2017] | 589(18)&nbsp;ns | IT | ¹⁶⁴Gd | (4−) | | |-id=Gadolinium-165 | ¹⁶⁵Gd | style="text-align:right" | 64 | style="text-align:right" | 101 | 164.9393171(14) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/165.pdf 1998] | 11.6(10)&nbsp;s | β⁻ | ¹⁶⁵Tb | 1/2−# | | |-id=Gadolinium-166 | ¹⁶⁶Gd | style="text-align:right" | 64 | style="text-align:right" | 102 | 165.9416304(17) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/166.pdf 2005] | 5.1(8)&nbsp;s | β⁻ | ¹⁶⁶Tb | 0+ | | |-id=Gadolinium-166m | style="text-indent:1em" | ^166mGd | colspan="3" style="text-indent:2em" | 1601.5(11)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/64/166Gd-1.pdf 2014] | 950(60)&nbsp;ns | IT | ¹⁶⁶Gd | (6−) | | |-id=Gadolinium-167 | ¹⁶⁷Gd | style="text-align:right" | 64 | style="text-align:right" | 103 | 166.9454900(56) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/167.pdf 2012] | 4.2(3)&nbsp;s | β⁻ | ¹⁶⁷Tb | 5/2−# | | |-id=Gadolinium-168 | ¹⁶⁸Gd | style="text-align:right" | 64 | style="text-align:right" | 104 | 167.94831(32)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/168.pdf 2012] | 3.03(16)&nbsp;s | β⁻ | ¹⁶⁸Tb | 0+ | | |-id=Gadolinium-169 | rowspan=2|¹⁶⁹Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 105 | rowspan=2|168.95288(43)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/169.pdf 2012] | rowspan=2|750(210)&nbsp;ms | β⁻ | ¹⁶⁹Tb | rowspan=2|7/2−# | rowspan=2| | rowspan=2| |- | β⁻, n? (<0.7%)<ref name=Ln922>{{cite journal |last1=Kiss |first1=G. G. |last2=Vitéz-Sveiczer |first2=A. |last3=Saito |first3=Y. |display-authors=et al. |title=Measuring the β-decay properties of neutron-rich exotic Pm, Sm, Eu, and Gd isotopes to constrain the nucleosynthesis yields in the rare-earth region |journal=The Astrophysical Journal |volume=936 |issue=107 |date=2022 |page=107 |doi=10.3847/1538-4357/ac80fc|bibcode=2022ApJ...936..107K |doi-access=free |hdl=2117/375253 |hdl-access=free }}</ref><!--only half-lives updated on 2022-11-29--> | ¹⁶⁸Tb |-id=Gadolinium-170 | rowspan=2|¹⁷⁰Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 106 | rowspan=2|169.95615(54)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/170.pdf 2012] | rowspan=2|{{val|675|94|75|u=ms}}<ref name=Ln922/> | β⁻ | ¹⁷⁰Tb | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁻, n? (<3%)<ref name=Ln922/> | ¹⁶⁹Tb |-id=Gadolinium-171 | rowspan=2|¹⁷¹Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 107 | rowspan=2|170.96113(54)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/171.pdf 2018] | rowspan=2|{{val|392|145|136|u=ms}}<ref name=Ln922/> | β⁻ | ¹⁷¹Tb | rowspan=2|9/2+# | rowspan=2| | rowspan=2| |- | β⁻, n? (<10%)<ref name=Ln922/> | ¹⁷⁰Tb |-id=Gadolinium-172 | rowspan=2|¹⁷²Gd | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 108 | rowspan=2|171.96461(32)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/172.pdf 2022] | rowspan=2|{{val|163|113|99|u=ms}}<ref name=Ln922/> | β⁻ | ¹⁷²Tb | rowspan=2|0+# | rowspan=2| | rowspan=2| |- | β⁻, n? (<50%)<ref name=Ln922/> | ¹⁷¹Tb |-id=Gadolinium-173 | ¹⁷³Gd<ref name="sumikama2026">{{cite journal |last1=Sumikama |first1=Toshiyuki |last2=Fukuda |first2=Naoki |last3=Kubo |first3=Toshiyuki |last4=Suzuki |first4=Hiroshi |last5=Takeda |first5=Hiroyuki |last6=Inabe |first6=Naohito |last7=Kameda |first7=Daisuke |last8=Ahn |first8=Deuk Soon |last9=Murai |first9=Daichi |last10=Yoshida |first10=Koichi |last11=Kusaka |first11=Kensuke |last12=Yanagisawa |first12=Yoshiyuki |last13=Ohtake |first13=Masao |last14=Shimizu |first14=Yohei |last15=Sato |first15=Yuki |last16=Sato |first16=Hiromi |last17=Otsu |first17=Hideaki |last18=Baba |first18=Hidetada |last19=Lorusso |first19=Giuseppe |last20=Söderström |first20=Pär-Anders |last21=Isobe |first21=Tadaaki |last22=Imai |first22=Nobuaki |last23=Mukai |first23=Momo |last24=Kimura |first24=Sota |last25=Miyatake |first25=Hiroari |last26=Iwasa |first26=Naohito |last27=Yagi |first27=Ayumi |last28=Yokoyama |first28=Rin |last29=Tarasov |first29=Oleg Borisovich |last30=Geissel |first30=Hans |title=Expanding the Isotopic Frontier: Seven New Neutron-Rich Rare-Earth Isotopes Observed at RIKEN RI Beam Factory |journal=Journal of the Physical Society of Japan |date=15 February 2026 |volume=95 |issue=2 |doi=10.7566/JPSJ.95.024202}}</ref> | style="text-align:right" | 64 | style="text-align:right" | 109 | | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/64/173.pdf 2026] | >310&nbsp;ns | | | | | {{Isotopes table/footer}}

==Gadolinium-148== As a pure alpha emitter with a half-life of {{val|86.9|3.9|u=years}} (the same as plutonium-238 within error),<ref name="148Gd"/> gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.<ref>{{cite book|year=2009|doi=10.17226/12653|title=Radioisotope Power Systems: An Imperative for Maintaining U.S. Leadership in Space Exploration|isbn=978-0-309-13857-4|last1=National Research Council of the National Academies|last2=Division on Engineering Physical Sciences|last3=Aeronautics Space Engineering Board|last4=Space Studies Board|last5=Radioisotope Power Systems Committee|citeseerx=10.1.1.367.4042}}</ref>

==Gadolinium-153== Gadolinium-153 has a half-life of 240.6&nbsp;days and emits gamma radiation with strong peaks at 41 keV and 102&nbsp;keV. It is used as a gamma ray source for X-ray absorptiometry and fluorescence, for bone density gauges for osteoporosis screening, and for radiometric profiling in the Lixiscope portable x-ray imaging system, also known as the Lixi Profiler. In nuclear medicine, it serves to calibrate the equipment needed like single-photon emission computed tomography systems (SPECT) to make x-rays. It ensures that the machines work correctly to produce images of radioisotope distribution inside the patient. This isotope is produced in a nuclear reactor from europium or enriched gadolinium.<ref>{{cite web|url=http://radioisotopes.pnl.gov/gadolinium.stm |title=PNNL: Isotope Sciences Program – Gadolinium-153 |work=pnl.gov |url-status=dead |archive-url=https://web.archive.org/web/20090527014921/http://radioisotopes.pnl.gov/gadolinium.stm |archive-date=2009-05-27 }}</ref> It can also detect the loss of calcium in the hip and back bones, allowing the ability to diagnose osteoporosis.<ref>{{cite web|title=Gadolinium|url=http://nobel.scas.bcit.ca/resource/ptable/gd.htm|work=BCIT Chemistry Resource Center|publisher=British Columbia Institute of Technology|access-date=30 March 2011|archive-date=23 August 2011|archive-url=https://web.archive.org/web/20110823085358/http://nobel.scas.bcit.ca/resource/ptable/gd.htm|url-status=dead}}</ref>

== See also == '''Daughter products other than gadolinium''' * Isotopes of terbium * Isotopes of europium * Isotopes of samarium * Isotopes of promethium

== References == {{reflist}}

{{Navbox element isotopes}}

Category:Isotopes of gadolinium Category:Gadolinium Gadolinium