Isotopes of gadolinium

Isotopes of gadolinium (₆₄Gd)
Standard atomic weight Ar°(Gd)
	157.25±0.03; 157.25±0.03 (abridged);
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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 (t_1/2 = 110 seconds), ^145mGd (t_1/2 = 85 seconds) and ^141mGd (t_1/2 = 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) ^{[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]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 5]}			Half-life ^{[n 4]}^{[n 5]}	Decay mode ^{[n 6]}	Daughter isotope ^{[n 7]}^{[n 8]}	Spin and parity ^{[n 9]}^{[n 5]}	Normal proportion	Range of variation
¹³⁵Gd	64	71	134.95250(43)#	1.1(2) s	β⁺ (98%)	¹³⁵Eu	(5/2+)
¹³⁵Gd	64	71	134.95250(43)#	1.1(2) s	β⁺, p (98%)	¹³⁴Sm	(5/2+)
¹³⁶Gd	64	72	135.94730(32)#	1# s [>200 ns]	β⁺?	¹³⁶Eu	0+
¹³⁶Gd	64	72	135.94730(32)#	1# s [>200 ns]	β⁺, p?	¹³⁵Sm	0+
¹³⁷Gd	64	73	136.94502(32)#	2.2(2) s	β⁺	¹³⁷Eu	(7/2)+#
¹³⁷Gd	64	73	136.94502(32)#	2.2(2) s	β⁺, p?	¹³⁶Sm	(7/2)+#
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−#
¹³⁹Gd	64	75	138.93813(21)#	5.7(3) s	β⁺, p?	¹³⁸Sm	9/2−#
^139mGd	250(150)# keV			4.8(9) s	β⁺	¹³⁹Eu	1/2+#
^139mGd	250(150)# keV			4.8(9) s	β⁺, p?	¹³⁸Sm	1/2+#
¹⁴⁰Gd	64	76	139.933674(30)	15.8(4) s	β⁺ (67(8)%)	¹⁴⁰Eu	0+
¹⁴⁰Gd	64	76	139.933674(30)	15.8(4) s	EC (33(8)%)	¹⁴⁰Eu	0+
¹⁴¹Gd	64	77	140.932126(21)	14(4) s	β⁺ (99.97%)	¹⁴¹Eu	(1/2+)
¹⁴¹Gd	64	77	140.932126(21)	14(4) s	β⁺, p (0.03%)	¹⁴⁰Sm	(1/2+)
^141mGd	377.76(9) keV			24.5(5) s	β⁺ (89%)	¹⁴¹Eu	(11/2−)
^141mGd	377.76(9) keV			24.5(5) s	IT (11%)	¹⁴¹Gd	(11/2−)
¹⁴²Gd	64	78	141.928116(30)	70.2(6) s	EC (52(5)%)	¹⁴²Eu	0+
¹⁴²Gd	64	78	141.928116(30)	70.2(6) s	β⁺ (48(5)%)	¹⁴²Eu	0+
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−
^145mGd	749.1(2) keV			85(3) s	β⁺ (5.7%)	¹⁴⁵Eu	11/2−
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 10]}	¹⁴⁴Sm	0+
¹⁴⁹Gd	64	85	148.919341(4)	9.28(10) d	β⁺	¹⁴⁹Eu	7/2−
¹⁴⁹Gd	64	85	148.919341(4)	9.28(10) d	α (4.34×10⁻⁴%)	¹⁴⁵Sm	7/2−
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−
¹⁵¹Gd	64	87	150.920348(4)	124(1) d	α (1.1(6)×10⁻⁶%)	¹⁴⁷Sm	7/2−
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^[6]	β⁻	¹⁷⁰Tb	0+
¹⁷¹Gd	64	107		392+145 −136 ms^[6]	β⁻	¹⁷¹Tb
¹⁷²Gd	64	108		163+113 −99 ms^[6]	β⁻	¹⁷²Tb	0+
This table header & footer: view

^ ^mGd – Excited nuclear isomer.
^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
^ Bold half-life – nearly stable, half-life longer than age of universe.
^ ^a ^b ^c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
^ Modes of decay:

EC: Electron capture

IT: Isomeric transition
^ Bold italics symbol as daughter – Daughter product is nearly stable.
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ Theorized to also undergo β⁺β⁺ decay to ¹⁴⁸Sm
^ Theorized to also undergo β⁺β⁺ decay to ¹⁵⁰Sm
^ primordial radionuclide
^ Theorized to also undergo β⁺β⁺ decay to ¹⁵²Sm
^ Believed to undergo α decay to ¹⁵⁰Sm
^ ^a ^b ^c ^d ^e ^f Fission product
^ Believed to undergo α decay to ¹⁵¹Sm
^ 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,^[2] gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.^[7]

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.^[8] It can also detect the loss of calcium in the hip and back bones, allowing the ability to diagnose osteoporosis.^[9]

References

^ 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.
^ ^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. Elsevier BV. 194: 110708. doi:10.1016/j.apradiso.2023.110708. ISSN 0969-8043.
^ "Standard Atomic Weights: Gadolinium". CIAAW. 1969.
^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (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.
^ 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.
^ ^a ^b ^c 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.
^ 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.
^ "PNNL: Isotope Sciences Program – Gadolinium-153". pnl.gov. Archived from the original on 2009-05-27.
^ "Gadolinium". BCIT Chemistry Resource Center. British Columbia Institute of Technology. Archived from the original on 23 August 2011. Retrieved 30 March 2011.

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, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- 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.
"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
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, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

[6] Gd – Excited nuclear isomer.

[7] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-8] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[9] Bold half-life – nearly stable, half-life longer than age of universe.

[TNN-10] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[11] Modes of decay:

EC: Electron capture

IT: Isomeric transition

[12] Bold italics symbol as daughter – Daughter product is nearly stable.

[13] Bold symbol as daughter – Daughter product is stable.

[14] ( ) spin value – Indicates spin with weak assignment arguments.

[15] Theorized to also undergo β⁺β⁺ decay to ¹⁴⁸Sm

[16] Theorized to also undergo β⁺β⁺ decay to ¹⁵⁰Sm

[17] rimordial radionuclide

[18] Theorized to also undergo β⁺β⁺ decay to ¹⁵²Sm

[19] Believed to undergo α decay to ¹⁵⁰Sm

[FP-20] ^ ^a ^b ^c ^d ^e ^f Fission product

[21] Believed to undergo α decay to ¹⁵¹Sm

[22] Believed to undergo β⁻β⁻ decay to ¹⁶⁰Dy with a half-life over 1.3×10²¹ years

[NUBASE2020-1] 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.

[148Gd-2] Chiera, Nadine M.; Dressler, Rugard; Sprung, Peter; Talip, Zeynep; Schumann, Dorothea (2023). "Determination of the half-life of gadolinium-148". Applied Radiation and Isotopes. Elsevier BV. 194: 110708. doi:10.1016/j.apradiso.2023.110708. ISSN 0969-8043.

[3] "Standard Atomic Weights: Gadolinium". CIAAW. 1969.

[CIAAW2021-4] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (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.

[DBD-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.

[Ln922-23] 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.

[24] 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.

[25] "PNNL: Isotope Sciences Program – Gadolinium-153". pnl.gov. Archived from the original on 2009-05-27.

[26] "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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