Isotopes of gadolinium (original) (raw)

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Isotopes of gadolinium (64Gd)

Main isotopes[1] Decay abun­dance half-life (_t_1/2) mode pro­duct 148Gd synth 86.9 y[2] α 144Sm 150Gd synth 1.79×106 y α 146Sm 152Gd 0.2% 1.08×1014 y α 148Sm 153Gd synth 240.6 d ε 153Eu 154Gd 2.18% stable 155Gd 14.8% stable 156Gd 20.5% stable 157Gd 15.7% stable 158Gd 24.8% stable 160Gd 21.9% stable
Standard atomic weight _A_r°(Gd)
157.249±0.002[3]157.25±0.01 (abridged)[4]
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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.[5]

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.

| Nuclide[n 1] | Z | N | Isotopic mass (Da)[6][n 2][n 3] | Half-life[1][n 4][n 5] | Decay mode[1][n 6] | Daughter isotope[n 7][n 8] | Spin andparity[1][n 9][n 5] | Natural abundance (mole fraction) | | | ----------------------------------------------------------------------------------------------- | --------------------------------------------------- | ---------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------- | | | Excitation energy[n 5] | Normal proportion[1] | 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[n 10] | 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[2] | α[n 11] | 144Sm | 0+ | | | | 149Gd | 64 | 85 | 148.9193477(36) | 9.28(10) d | β+ | 149Eu | 7/2− | | | | α (4.3×10−4%) | 145Sm | | | | | | | | | | 150Gd | 64 | 86 | 149.9186639(65) | 1.79(8)×106 y | α[n 12] | 146Sm | 0+ | | | | 151Gd | 64 | 87 | 150.9203549(32) | 123.9(10) d | EC | 151Eu | 7/2− | | | | α (1.1×10−6%) | 147Sm | | | | | | | | | | 152Gd[n 13] | 64 | 88 | 151.9197984(11) | 1.08(8)×1014 y | α[n 14] | 148Sm | 0+ | 0.0020(1) | | | 153Gd | 64 | 89 | 152.9217569(11) | 240.6(7) d | EC | 153Eu | 3/2− | | | | 153m1Gd | 95.1737(8) keV | 3.5(4) μs | IT | 153Gd | 9/2+ | | | | | | 153m2Gd | 171.188(4) keV | 76.0(14) μs | IT | 153Gd | (11/2−) | | | | | | 154Gd | 64 | 90 | 153.9208730(11) | Observationally Stable[n 15] | 0+ | 0.0218(2) | | | | | 155Gd[n 16] | 64 | 91 | 154.9226294(11) | Observationally Stable[n 17] | 3/2− | 0.1480(9) | | | | | 155mGd | 121.10(19) keV | 31.97(27) ms | IT | 155Gd | 11/2− | | | | | | 156Gd[n 16] | 64 | 92 | 155.9221301(11) | Stable | 0+ | 0.2047(3) | | | | | 156mGd | 2137.60(5) keV | 1.3(1) μs | IT | 156Gd | 7- | | | | | | 157Gd[n 16] | 64 | 93 | 156.9239674(10) | Stable | 3/2− | 0.1565(4) | | | | | 157m1Gd | 63.916(5) keV | 460(40) ns | IT | 157Gd | 5/2+ | | | | | | 157m2Gd | 426.539(23) keV | 18.5(23) μs | IT | 157Gd | 11/2− | | | | | | 158Gd[n 16] | 64 | 94 | 157.9241112(10) | Stable | 0+ | 0.2484(8) | | | | | 159Gd[n 16] | 64 | 95 | 158.9263958(11) | 18.479(4) h | β− | 159Tb | 3/2− | | | | 160Gd[n 16] | 64 | 96 | 159.9270612(12) | Observationally Stable[n 18] | 0+ | 0.2186(3) | | | | | 161Gd | 64 | 97 | 160.9296763(16) | 3.646(3) min | β− | 161Tb | 5/2− | | | | 162Gd | 64 | 98 | 161.9309918(43) | 8.4(2) min | β− | 162Tb | 0+ | | | | 163Gd | 64 | 99 | 162.93409664(86) | 68(3) s | β− | 163Tb | 7/2+ | | | | 163mGd | 138.22(20) keV | 23.5(10) s | IT? | 163Gd | 1/2− | | | | | | β− | 163Tb | | | | | | | | | | 164Gd | 64 | 100 | 163.9359162(11) | 45(3) s | β− | 164Tb | 0+ | | | | 164mGd | 1095.8(4) keV | 589(18) ns | IT | 164Gd | (4−) | | | | | | 165Gd | 64 | 101 | 164.9393171(14) | 11.6(10) s | β− | 165Tb | 1/2−# | | | | 166Gd | 64 | 102 | 165.9416304(17) | 5.1(8) s | β− | 166Tb | 0+ | | | | 166mGd | 1601.5(11) keV | 950(60) ns | IT | 166Gd | (6−) | | | | | | 167Gd | 64 | 103 | 166.9454900(56) | 4.2(3) s | β− | 167Tb | 5/2−# | | | | 168Gd | 64 | 104 | 167.94831(32)# | 3.03(16) s | β− | 168Tb | 0+ | | | | 169Gd | 64 | 105 | 168.95288(43)# | 750(210) ms | β− | 169Tb | 7/2−# | | | | β−, n? (<0.7%)[7] | 168Tb | | | | | | | | | | 170Gd | 64 | 106 | 169.95615(54)# | 675+94−75 ms[7] | β− | 170Tb | 0+ | | | | β−, n? (<3%)[7] | 169Tb | | | | | | | | | | 171Gd | 64 | 107 | 170.96113(54)# | 392+145−136 ms[7] | β− | 171Tb | 9/2+# | | | | β−, n? (<10%)[7] | 170Tb | | | | | | | | | | 172Gd | 64 | 108 | 171.96461(32)# | 163+113−99 ms[7] | β− | 172Tb | 0+# | | | | β−, n? (<50%)[7] | 171Tb | | | | | | | | | | This table header & footer: view | | | | | | | | | |

  1. ^ mGd – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1_σ_) 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. ^ a b c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. ^ Modes of decay:
  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. ^ Order of ground state and isomer is uncertain.
  11. ^ Theorized to also undergo β+β+ decay to 148Sm
  12. ^ Theorized to also undergo β+β+ decay to 150Sm
  13. ^ primordial radionuclide
  14. ^ Theorized to also undergo β+β+ decay to 152Sm
  15. ^ Believed to undergo α decay to 150Sm
  16. ^ a b c d e f Fission product
  17. ^ Believed to undergo α decay to 151Sm
  18. ^ Believed to undergo β−β− decay to 160Dy with a half-life over 3.1×1019 years

With a half-life of 86.9±3.9 year via alpha decay alone,[2] gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.[8]

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.[9] It can also detect the loss of calcium in the hip and back bones, allowing the ability to diagnose osteoporosis.[10]

  1. ^ a b c d e Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ^ a b c Chiera, Nadine M.; Dressler, Rugard; Sprung, Peter; Talip, Zeynep; Schumann, Dorothea (2023). "Determination of the half-life of gadolinium-148". Applied Radiation and Isotopes. 194. Elsevier BV: 110708. doi:10.1016/j.apradiso.2023.110708. ISSN 0969-8043.
  3. ^ "Standard Atomic Weights: Gadolinium". CIAAW. 2024.
  4. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  5. ^ F. A. Danevich; et al. (2001). "Quest for double beta decay of 160Gd and Ce isotopes". Nuclear Physics A. 694 (1–2): 375–391. arXiv:nucl-ex/0011020. Bibcode:2001NuPhA.694..375D. doi:10.1016/S0375-9474(01)00983-6. S2CID 11874988.
  6. ^ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  7. ^ a b c d e f g Kiss, G. G.; Vitéz-Sveiczer, A.; Saito, Y.; et al. (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. Bibcode:2022ApJ...936..107K. doi:10.3847/1538-4357/ac80fc. hdl:2117/375253.
  8. ^ 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. CiteSeerX 10.1.1.367.4042. doi:10.17226/12653. ISBN 978-0-309-13857-4.
  9. ^ "PNNL: Isotope Sciences Program – Gadolinium-153". pnl.gov. Archived from the original on 2009-05-27.
  10. ^ "Gadolinium". BCIT Chemistry Resource Center. British Columbia Institute of Technology. Archived from the original on 23 August 2011. Retrieved 30 March 2011.