Isotopes of 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

|-id=Gadolinium-133 | ¹³³Gd | style="text-align:right" | 64 | style="text-align:right" | 69 | 132.96129(54)# | 10#&nbsp;ms<br>[>310&nbsp;ns] | | | 5/2+# | | |-id=Gadolinium-134 | ¹³⁴Gd | style="text-align:right" | 64 | style="text-align:right" | 70 | 133.95542(43)# | 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|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 | rowspan=2 style="text-align:right" | 64 | rowspan=2 style="text-align:right" | 72 | rowspan=2|135.94730(32)# | 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|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)# | 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 | 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|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 | rowspan=2 colspan="3" style="text-indent:2em" | 250(150)#&nbsp;keV | 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|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|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|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|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|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|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) | 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 | 145(30)&nbsp;ns | IT | ¹⁴⁴Gd | (10+) | | |-id=Gadolinium-145 | ¹⁴⁵Gd | style="text-align:right" | 64 | style="text-align:right" | 81 | 144.921710(21) | 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|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) | 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) | 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 | 510(20)&nbsp;ns | IT | ¹⁴⁷Gd | 49/2+ | | |- | ¹⁴⁸Gd | style="text-align:right" | 64 | style="text-align:right" | 84 | 147.9181214(16) | 86.9(39)&nbsp;y | α | 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|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) |1.79(8)×10⁶&nbsp;y | α | 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|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 | style="text-align:right" | 64 | style="text-align:right" | 88 | 151.9197984(11) | 1.08(8)×10¹⁴&nbsp;y | α | ¹⁴⁸Sm | 0+ | 0.0020(1) | |- | ¹⁵³Gd | style="text-align:right" | 64 | style="text-align:right" | 89 | 152.9217569(11) | 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 | 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 | 76.0(14)&nbsp;μs | IT | ¹⁵³Gd | (11/2−) | | |-id=Gadolinium-154 | ¹⁵⁴Gd | style="text-align:right" | 64 | style="text-align:right" | 90 | 153.9208730(11) | colspan="3" style="text-align:center;"|Observationally Stable | 0+ | 0.0218(2) | |-id=Gadolinium-155 | ¹⁵⁵Gd | style="text-align:right" | 64 | style="text-align:right" | 91 | 154.9226294(11) | colspan="3" style="text-align:center;"|Observationally Stable | 3/2− | 0.1480(9) | |-id=Gadolinium-155m | style="text-indent:1em" | ^155mGd | colspan="3" style="text-indent:2em" | 121.10(19)&nbsp;keV | 31.97(27)&nbsp;ms | IT | ¹⁵⁵Gd | 11/2− | | |-id=Gadolinium-156 | ¹⁵⁶Gd | style="text-align:right" | 64 | style="text-align:right" | 92 | 155.9221301(11) | 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 | 1.3(1)&nbsp;μs | IT | ¹⁵⁶Gd | 7- | | |-id=Gadolinium-157 | ¹⁵⁷Gd | style="text-align:right" | 64 | style="text-align:right" | 93 | 156.9239674(10) | 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 | 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 | 18.5(23)&nbsp;μs | IT | ¹⁵⁷Gd | 11/2− | | |-id=Gadolinium-158 | ¹⁵⁸Gd | style="text-align:right" | 64 | style="text-align:right" | 94 | 157.9241112(10) | colspan="3" style="text-align:center;"|Stable | 0+ | 0.2484(8) | |-id=Gadolinium-159 | ¹⁵⁹Gd | style="text-align:right" | 64 | style="text-align:right" | 95 | 158.9263958(11) | 18.479(4)&nbsp;h | β^− | ¹⁵⁹Tb | 3/2− | | |-id=Gadolinium-160 | ¹⁶⁰Gd | style="text-align:right" | 64 | style="text-align:right" | 96 | 159.9270612(12) | colspan="3" style="text-align:center;"|Observationally Stable | 0+ | 0.2186(3) | |-id=Gadolinium-161 | ¹⁶¹Gd | style="text-align:right" | 64 | style="text-align:right" | 97 | 160.9296763(16) | 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) | 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) | 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|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) | 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 | 589(18)&nbsp;ns | IT | ¹⁶⁴Gd | (4−) | | |-id=Gadolinium-165 | ¹⁶⁵Gd | style="text-align:right" | 64 | style="text-align:right" | 101 | 164.9393171(14) | 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) | 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 | 950(60)&nbsp;ns | IT | ¹⁶⁶Gd | (6−) | | |-id=Gadolinium-167 | ¹⁶⁷Gd | style="text-align:right" | 64 | style="text-align:right" | 103 | 166.9454900(56) | 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)# | 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|750(210)&nbsp;ms | β^− | ¹⁶⁹Tb | rowspan=2|7/2−# | rowspan=2| | rowspan=2| |- | β^−, n? (<0.7%) | 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| | β^− | ¹⁷⁰Tb | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β^−, n? (<3%) | 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| | β^− | ¹⁷¹Tb | rowspan=2|9/2+# | rowspan=2| | rowspan=2| |- | β^−, n? (<10%) | 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| | β^− | ¹⁷²Tb | rowspan=2|0+# | rowspan=2| | rowspan=2| |- | β^−, n? (<50%) | ¹⁷¹Tb |-id=Gadolinium-173 | ¹⁷³Gd | style="text-align:right" | 64 | style="text-align:right" | 109 | | >310&nbsp;ns | | | | |

Gadolinium-148

As a pure alpha emitter with a half-life of (the same as plutonium-238 within error), gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.

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. It can also detect the loss of calcium in the hip and back bones, allowing the ability to diagnose osteoporosis.

See also

Daughter products other than gadolinium

• Isotopes of terbium
• Isotopes of europium
• Isotopes of samarium
• Isotopes of promethium

References