Isotopes of gadolinium

Short description: Nuclides with atomic number of 64 but with different mass numbers

Main isotopes of Chemistry:gadolinium (64Gd) | Iso­tope | Decay

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| abun­dance | half-life (t1/2) | mode | pro­duct
148Gd  | syn | 75 y  | α | 144Sm
150Gd  | syn  | 1.8×106 y  | α  | 146Sm
152Gd  | 0.20%  | 1.08×1014 y  | α  | 148Sm
153Gd  | syn  | 240.4 d  | ε | 153Eu
γ | –
154Gd  | 2.18%  | stable
155Gd  | 14.80%  | stable
156Gd  | 20.47%  | stable
157Gd  | 15.65%  | stable
158Gd  | 24.84%  | stable
160Gd  | 21.86%  | stable
Standard atomic weight Ar, standard(Gd)|

* 157.25(3)[1]

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Naturally occurring gadolinium (64Gd) is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance). The predicted double beta decay of 160Gd has never been observed; only a lower limit on its half-life of more than 1.3×1021 years has been set experimentally.[2]

Thirty-three radioisotopes have been characterized, with the most stable being alpha-decaying 152Gd (naturally occurring) with a half-life of 1.08×1014 years, and 150Gd with a half-life of 1.79×106 years. All of the remaining radioactive isotopes have half-lives less than 100 years, the majority of these having half-lives less than 24.6 seconds. Gadolinium isotopes have 10 metastable isomers, with the most stable being 143mGd (t1/2 = 110 seconds), 145mGd (t1/2 = 85 seconds) and 141mGd (t1/2 = 24.5 seconds).

The primary decay mode at atomic weights lower than the most abundant stable isotope, 158Gd, is electron capture, and the primary mode at higher atomic weights is beta decay. The primary decay products for isotopes lighter than 158Gd are isotopes of europium and the primary products of heavier isotopes are isotopes of terbium.

## Contents

* 1 List of isotopes
* 2 Gadolinium-148
* 3 Gadolinium-153
* 4 References

## List of isotopes

Nuclide
[n 1] | Z | N | Isotopic mass (u)
[n 2][n 3] | Half-life
[n 4][n 5] | Decay
mode
[n 6] | Daughter
isotope
[n 7][n 8] | Spin and
parity
[n 9][n 5] | Physics:Natural abundance (mole fraction)

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Excitation energy[n 5] | Normal proportion  | Range of variation
135Gd  | 64  | 71  | 134.95250(43)#  | 1.1(2) s  | β+ (98%)  | 135Eu  | (5/2+)  |  |
β+, p (98%)  | 134Sm
136Gd  | 64  | 72  | 135.94730(32)#  | 1# s [>200 ns]  | β+?  | 136Eu  | 0+  |  |
β+, p?  | 135Sm
137Gd  | 64  | 73  | 136.94502(32)#  | 2.2(2) s  | β+ | 137Eu  | (7/2)+#  |  |
β+, p?  | 136Sm
138Gd  | 64  | 74  | 137.94025(22)#  | 4.7(9) s  | β+ | 138Eu  | 0+  |  |
138mGd  | 2232.6(11) keV  | 6.2(0.2) μs  | IT  | 138Gd  | (8−)  |  |
139Gd  | 64  | 75  | 138.93813(21)#  | 5.7(3) s  | β+ | 139Eu  | 9/2−#  |  |
β+, p?  | 138Sm
139mGd  | 250(150)# keV  | 4.8(9) s  | β+ | 139Eu  | 1/2+#  |  |
β+, p?  | 138Sm
140Gd  | 64  | 76  | 139.933674(30)  | 15.8(4) s  | β+ (67(8)%)  | 140Eu  | 0+  |  |
EC (33(8)%)
141Gd  | 64  | 77  | 140.932126(21)  | 14(4) s  | β+ (99.97%)  | 141Eu  | (1/2+)  |  |
β+, p (0.03%)  | 140Sm
141mGd  | 377.76(9) keV  | 24.5(5) s  | β+ (89%)  | 141Eu  | (11/2−)  |  |
IT (11%)  | 141Gd
142Gd  | 64  | 78  | 141.928116(30)  | 70.2(6) s  | EC (52(5)%)  | 142Eu  | 0+  |  |
β+ (48(5)%)
143Gd  | 64  | 79  | 142.92675(22)  | 39(2) s  | β+ | 143Eu  | 1/2+  |  |
β+, p?  | 142Sm
β+, α?  | 139Pm
143mGd  | 152.6(5) keV  | 110.0(14) s  | β+ | 143Eu  | 11/2−  |  |
β+, p?  | 142Sm
β+, α?  | 139Pm
144Gd  | 64  | 80  | 143.922963(30)  | 4.47(6) min  | β+ | 144Eu  | 0+  |  |
144mGd  | 3433.1(5) keV  | 145(30) ns  | IT  | 144Gd  | (10+)  |  |
145Gd  | 64  | 81  | 144.921710(21)  | 23.0(4) min  | β+ | 145Eu  | 1/2+  |  |
145mGd  | 749.1(2) keV  | 85(3) s  | IT (94.3%)  | 145Gd  | 11/2−  |  |
β+ (5.7%)  | 145Eu
146Gd  | 64  | 82  | 145.9183185(44)  | 48.27(10) d  | EC  | 146Eu  | 0+  |  |
147Gd  | 64  | 83  | 146.9191010(20)  | 38.06(12) h  | β+ | 147Eu  | 7/2−  |  |
147mGd  | 8587.8(5) keV  | 510(20) ns  | IT  | 147Gd  | 49/2+  |  |
148Gd  | 64  | 84  | 147.9181214(16)  | 86.9(39) y[3] | α[n 10] | 144Sm | 0+  |
149Gd  | 64  | 85  | 148.919341(4)  | 9.28(10) d  | β+ | 149Eu  | 7/2−  |  |
α (4.34×10−4%)  | 145Sm
150Gd  | 64  | 86  | 149.918659(7)  | 1.79(8)×106 y  | α[n 11] | 146Sm  | 0+  |  |
151Gd  | 64  | 87  | 150.920348(4)  | 124(1) d  | EC  | 151Eu | 7/2−  |  |
α (1.1(6)×10−6%)  | 147Sm
152Gd[n 12] | 64  | 88  | 151.9197910(27)  | 1.08(8)×1014 y | α[n 13] | 148Sm | 0+  | 0.0020(1)  |
153Gd  | 64  | 89  | 152.9217495(27)  | 240.4(10) d  | EC  | 153Eu | 3/2−  |  |
153m1Gd  | 95.1737(12) keV  | 3.5(4) µs  |  |  | (9/2+)  |  |
153m2Gd  | 171.189(5) keV  | 76.0(14) µs  |  |  | (11/2−)  |  |
154Gd  | 64  | 90  | 153.9208656(27)  | Observationally Stable[n 14] | 0+  | 0.0218(3)  |
155Gd[n 15] | 64  | 91  | 154.9226220(27)  | Observationally Stable[n 16] | 3/2−  | 0.1480(12)  |
155mGd  | 121.05(19) keV  | 31.97(27) ms  | IT  | 155Gd | 11/2−  |  |
156Gd[n 15] | 64  | 92  | 155.9221227(27)  | Stable | 0+  | 0.2047(9)  |
156mGd  | 2137.60(5) keV  | 1.3(1) µs  |  |  | 7-  |  |
157Gd[n 15] | 64  | 93  | 156.9239601(27)  | Stable | 3/2−  | 0.1565(2)  |
158Gd[n 15] | 64  | 94  | 157.9241039(27)  | Stable | 0+  | 0.2484(7)  |
159Gd[n 15] | 64  | 95  | 158.9263887(27)  | 18.479(4) h  | β− | 159Tb | 3/2−  |  |
160Gd[n 15] | 64  | 96  | 159.9270541(27)  | Observationally Stable[n 17] | 0+  | 0.2186(19)  |
161Gd  | 64  | 97  | 160.9296692(29)  | 3.646(3) min  | β− | 161Tb  | 5/2−  |  |
162Gd  | 64  | 98  | 161.930985(5)  | 8.4(2) min  | β− | 162Tb  | 0+  |  |
163Gd  | 64  | 99  | 162.93399(32)#  | 68(3) s  | β− | 163Tb  | 7/2+#  |  |
164Gd  | 64  | 100  | 163.93586(43)#  | 45(3) s  | β− | 164Tb  | 0+  |  |
165Gd  | 64  | 101  | 164.93938(54)#  | 10.3(16) s  | β− | 165Tb  | 1/2−#  |  |
166Gd  | 64  | 102  | 165.94160(64)#  | 4.8(10) s  | β− | 166Tb  | 0+  |  |
167Gd  | 64  | 103  | 166.94557(64)#  | 4.2(3) s  | β− | 167Tb  | 5/2−#  |  |
168Gd  | 64  | 104  | 167.94836(75)#  | 3.03(16) s  | β− | 168Tb  | 0+  |  |
169Gd  | 64  | 105  | 168.95287(86)#  | 750(210) ms  | β− | 169Tb  | 7/2−#  |  |
170Gd  | 64  | 106  |  | 675+94
−75 ms[4] | β− | 170Tb  | 0+  |  |
171Gd  | 64  | 107  |  | 392+145
−136 ms[4] | β− | 171Tb  |  |  |
172Gd  | 64  | 108  |  | 163+113
−99 ms[4] | β− | 172Tb  | 0+  |  |

1. ↑ mGd - Excited nuclear isomer.
2. ↑ ( ) - Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. ↑ # - Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. ↑ Bold half-life - nearly stable, half-life longer than age of universe.
5. ↑ 5.0 5.1 5.2 # - Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
6. ↑ Modes of decay:  EC: | Electron capture

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IT: | Isomeric transition
7. ↑ Bold italics symbol as daughter - Daughter product is nearly stable.
8. ↑ Bold symbol as daughter - Daughter product is stable.
9. ↑ ( ) spin value - Indicates spin with weak assignment arguments.
10. ↑ Theorized to also undergo β+β+ decay to 148Sm
11. ↑ Theorized to also undergo β+β+ decay to 150Sm
12. ↑ primordial radionuclide
13. ↑ Theorized to also undergo β+β+ decay to 152Sm
14. ↑ Believed to undergo α decay to 150Sm
15. ↑ 15.0 15.1 15.2 15.3 15.4 15.5 Fission product
16. ↑ Believed to undergo α decay to 151Sm
17. ↑ Believed to undergo β−β− decay to 160Dy with a half-life over 1.3×1021 years

## Gadolinium-148

With a half-life of 86.9±3.9 year via alpha decay alone,[3] gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.[5]

## Gadolinium-153

Gadolinium-153 has a half-life of 240.4±10 d and emits gamma radiation with strong peaks at 41 keV and 102 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.[6] It can also detect the loss of calcium in the hip and back bones, allowing the ability to diagnose osteoporosis.[7]

## References

1. ↑ Meija, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry 88 (3): 265–91. doi:10.1515/pac-2015-0305.
2. ↑ F. A. Danevich (2001). "Quest for double beta decay of 160Gd and Ce isotopes". Nuclear Physics A 694 (1–2): 375–391. doi:10.1016/S0375-9474(01)00983-6. Bibcode: 2001NuPhA.694..375D.
3. ↑ 3.0 3.1 Cite error: Invalid `<ref>` tag; no text was provided for refs named `148Gd`
4. ↑ 4.0 4.1 4.2 Kiss, G. G.Expression error: Unrecognized word "et". (2022). "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". The Astrophysical Journal 936 (107): 107. doi:10.3847/1538-4357/ac80fc. Bibcode: 2022ApJ...936..107K.
5. ↑ Council, National Research; Sciences, Division on Engineering Physical; Board, Aeronautics Space Engineering; Board, Space Studies; Committee, Radioisotope Power Systems (2009). Radioisotope Power Systems: An Imperative for Maintaining U.S. Leadership in Space Exploration. doi:10.17226/12653. ISBN 978-0-309-13857-4.
6. ↑ "PNNL: Isotope Sciences Program – Gadolinium-153". pnl.gov. http://radioisotopes.pnl.gov/gadolinium.stm.
7. ↑ "Gadolinium". BCIT Chemistry Resource Center. British Columbia Institute of Technology. http://nobel.scas.bcit.ca/resource/ptable/gd.htm.

* Isotope masses from:
* Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A 729: 3–128, doi:10.1016/j.nuclphysa.2003.11.001, Bibcode: 2003NuPhA.729....3A, https://hal.archives-ouvertes.fr/in2p3-00020241/document
* Isotopic compositions and standard atomic masses from:
* Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051.
* Half-life, spin, and isomer data selected from the following sources.
* Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A 729: 3–128, doi:10.1016/j.nuclphysa.2003.11.001, Bibcode: 2003NuPhA.729....3A, https://hal.archives-ouvertes.fr/in2p3-00020241/document
* National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/.
* Lide, David R., ed (2004). "11. Table of the Isotopes". CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

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