Isotopes of gadolinium

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Isotopes of gadolinium  (64Gd)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
148Gd synth 86.9 y [2] α 144Sm
150Gdsynth1.79×106 yα 146Sm
152Gd0.2%1.08×1014 yα 148Sm
153Gdsynth240.6 d ε 153Eu
154Gd2.18% stable
155Gd14.8%stable
156Gd20.5%stable
157Gd15.7%stable
158Gd24.8%stable
160Gd21.9%stable
Standard atomic weight Ar°(Gd)

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]

Contents

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.

List of isotopes


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 and
parity [1]
[n 9] [n 5] 		Natural abundance (mole fraction)
Excitation energy [n 5] Normal proportion [1] Range of variation
135Gd6471134.95250(43)#1.1(2) s β+ (98%)135Eu(5/2+)
β+, p (98%)134Sm
136Gd6472135.94730(32)#1# s [>200 ns]β+?136Eu0+
β+, p?135Sm
137Gd6473136.94502(32)#2.2(2) sβ+137Eu(7/2)+#
β+, p?136Sm
138Gd6474137.94025(22)#4.7(9) sβ+138Eu0+
138mGd2232.6(11) keV6.2(0.2) μs IT 138Gd(8−)
139Gd6475138.93813(21)#5.7(3) sβ+139Eu9/2−#
β+, p?138Sm
139mGd [n 10] 250(150)# keV4.8(9) sβ+139Eu1/2+#
β+, p?138Sm
140Gd6476139.933674(30)15.8(4) sβ+ (67(8)%)140Eu0+
EC (33(8)%)
141Gd6477140.932126(21)14(4) sβ+ (99.97%)141Eu(1/2+)
β+, p (0.03%)140Sm
141mGd377.76(9) keV24.5(5) sβ+ (89%)141Eu(11/2−)
IT (11%)141Gd
142Gd6478141.928116(30)70.2(6) sEC (52(5)%)142Eu0+
β+ (48(5)%)
143Gd6479142.92675(22)39(2) sβ+143Eu1/2+
β+, p?142Sm
β+, α?139Pm
143mGd152.6(5) keV110.0(14) sβ+143Eu11/2−
β+, p?142Sm
β+, α?139Pm
144Gd6480143.922963(30)4.47(6) minβ+144Eu0+
144mGd3433.1(5) keV145(30) nsIT144Gd(10+)
145Gd6481144.921710(21)23.0(4) minβ+145Eu1/2+
145mGd749.1(2) keV85(3) sIT (94.3%)145Gd11/2−
β+ (5.7%)145Eu
146Gd6482145.9183185(44)48.27(10) dEC146Eu0+
147Gd6483146.9191010(20)38.06(12) hβ+147Eu7/2−
147mGd8587.8(5) keV510(20) nsIT147Gd49/2+
148Gd6484147.9181214(16)86.9(39) y [2] α [n 11] 144Sm0+
149Gd6485148.9193477(36)9.28(10) dβ+149Eu7/2−
α (4.3×10−4%)145Sm
150Gd6486149.9186639(65)1.79(8)×106 yα [n 12] 146Sm0+
151Gd6487150.9203549(32)123.9(10) dEC151Eu7/2−
α (1.1×10−6%)147Sm
152Gd [n 13] 6488151.9197984(11)1.08(8)×1014 yα [n 14] 148Sm0+0.0020(1)
153Gd6489152.9217569(11)240.6(7) dEC153Eu3/2−
153m1Gd95.1737(8) keV3.5(4) μsIT153Gd9/2+
153m2Gd171.188(4) keV76.0(14) μsIT153Gd(11/2−)
154Gd6490153.9208730(11) Observationally Stable [n 15] 0+0.0218(2)
155Gd [n 16] 6491154.9226294(11)Observationally Stable [n 17] 3/2−0.1480(9)
155mGd121.10(19) keV31.97(27) msIT155Gd11/2−
156Gd [n 16] 6492155.9221301(11)Stable0+0.2047(3)
156mGd2137.60(5) keV1.3(1) μsIT156Gd7-
157Gd [n 16] 6493156.9239674(10)Stable3/2−0.1565(4)
157m1Gd63.916(5) keV460(40) nsIT157Gd5/2+
157m2Gd426.539(23) keV18.5(23) μsIT157Gd11/2−
158Gd [n 16] 6494157.9241112(10)Stable0+0.2484(8)
159Gd [n 16] 6495158.9263958(11)18.479(4) hβ−159Tb3/2−
160Gd [n 16] 6496159.9270612(12)Observationally Stable [n 18] 0+0.2186(3)
161Gd6497160.9296763(16)3.646(3) minβ−161Tb5/2−
162Gd6498161.9309918(43)8.4(2) minβ−162Tb0+
163Gd6499162.93409664(86)68(3) sβ−163Tb7/2+
163mGd138.22(20) keV23.5(10) sIT?163Gd1/2−
β−163Tb
164Gd64100163.9359162(11)45(3) sβ−164Tb0+
164mGd1095.8(4) keV589(18) nsIT164Gd(4−)
165Gd64101164.9393171(14)11.6(10) sβ−165Tb1/2−#
166Gd64102165.9416304(17)5.1(8) sβ−166Tb0+
166mGd1601.5(11) keV950(60) nsIT166Gd(6−)
167Gd64103166.9454900(56)4.2(3) sβ−167Tb5/2−#
168Gd64104167.94831(32)#3.03(16) sβ−168Tb0+
169Gd64105168.95288(43)#750(210) msβ−169Tb7/2−#
β−, n? (<0.7%) [7] 168Tb
170Gd64106169.95615(54)#675+94
−75 ms [7] 		β−170Tb0+
β−, n? (<3%) [7] 169Tb
171Gd64107170.96113(54)#392+145
−136 ms [7] 		β−171Tb9/2+#
β−, n? (<10%) [7] 170Tb
172Gd64108171.96461(32)#163+113
−99 ms [7] 		β−172Tb0+#
β−, n? (<50%) [7] 171Tb
This table header & footer:
  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. 1 2 3 # – 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
    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. ↑ 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. 1 2 3 4 5 6 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

Gadolinium-148

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

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]

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Naturally occurring ytterbium (70Yb) is composed of seven stable isotopes: 168Yb, 170Yb–174Yb, and 176Yb, with 174Yb being the most abundant. 30 radioisotopes have been characterized, with the most stable being 169Yb with a half-life of 32.014 days, 175Yb with a half-life of 4.185 days, and 166Yb with a half-life of 56.7 hours. All of the remaining radioactive isotopes have half-lives that are less than 2 hours, and the majority of these have half-lives that are less than 20 minutes. This element also has 18 meta states, with the most stable being 169mYb.

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References

  1. 1 2 3 4 5 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. 1 2 3 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. 1969.
  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. 1 2 3 4 5 6 7 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.
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