Isotopes of gadolinium

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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.

Quick facts Main isotopes, Decay ...

Isotopes of gadolinium (₆₄Gd)

Main isotopes^[1]			Decay
Isotope	abundance	half-life (t_1/2)	mode	product
¹⁴⁸Gd	synth	86.9 y^[2]	α	¹⁴⁴Sm
¹⁵⁰Gd	synth	1.79×10⁶ y	α	¹⁴⁶Sm
¹⁵¹Gd	synth	123.9 d	ε	¹⁵¹Eu
¹⁵¹Gd	synth	123.9 d	α	¹⁴⁷Sm
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
¹⁵⁹Gd	synth	18.479 h	β⁻	¹⁵⁹Tb
¹⁶⁰Gd	21.9%	stable

Standard atomic weight A_r°(Gd)

157.249±0.002^[3]
157.25±0.01 (abridged)^[4]

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

More information Nuclide, Z ...

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da)^[5] ^{[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)
Nuclide ^{[n 1]}	Excitation energy^{[n 5]}			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]}	Normal proportion^[1]	Range of variation
¹³³Gd^[6]	64	69	132.96129(54)#	10# ms [>310 ns]			5/2+#
¹³⁴Gd^[6]	64	70	133.95542(43)#	400# ms [>310 ns]			0+
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^[6]	64	72	135.94730(32)#	1# s [>310 ns]	β⁺?	¹³⁶Eu	0+
¹³⁶Gd^[6]	64	72	135.94730(32)#	1# s [>310 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^{[n 10]}	250(150)# keV			4.8(9) s	β⁺	¹³⁹Eu	1/2+#
^139mGd^{[n 10]}	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(9) 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−
¹⁴⁹Gd	64	85	148.9193477(36)	9.28(10) d	α (4.3×10⁻⁴%)	¹⁴⁵Sm	7/2−
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−
¹⁵¹Gd	64	87	150.9203549(32)	123.9(10) d	α (1.1×10⁻⁶%)	¹⁴⁷Sm	7/2−
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^{[n 15]}	64	90	153.9208730(11)	Observationally Stable^{[n 16]}			0+	0.0218(2)
¹⁵⁵Gd^{[n 15]}	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 15]}	64	92	155.9221301(11)	Stable			0+	0.2047(3)
^156mGd	2137.60(5) keV			1.3(1) μs	IT	¹⁵⁶Gd	7-
¹⁵⁷Gd^{[n 15]}	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 15]}	64	94	157.9241112(10)	Stable			0+	0.2484(8)
¹⁵⁹Gd^{[n 15]}	64	95	158.9263958(11)	18.479(4) h	β⁻	¹⁵⁹Tb	3/2−
¹⁶⁰Gd^{[n 15]}	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−
^163mGd	138.22(20) keV			23.5(10) s	β⁻	¹⁶³Tb	1/2−
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−#
¹⁶⁹Gd	64	105	168.95288(43)#	750(210) ms	β⁻, n? (<0.7%)^[7]	¹⁶⁸Tb	7/2−#
¹⁷⁰Gd	64	106	169.95615(54)#	675+94 −75 ms^[7]	β⁻	¹⁷⁰Tb	0+
¹⁷⁰Gd	64	106	169.95615(54)#	675+94 −75 ms^[7]	β⁻, n? (<3%)^[7]	¹⁶⁹Tb	0+
¹⁷¹Gd	64	107	170.96113(54)#	392+145 −136 ms^[7]	β⁻	¹⁷¹Tb	9/2+#
¹⁷¹Gd	64	107	170.96113(54)#	392+145 −136 ms^[7]	β⁻, n? (<10%)^[7]	¹⁷⁰Tb	9/2+#
¹⁷²Gd	64	108	171.96461(32)#	163+113 −99 ms^[7]	β⁻	¹⁷²Tb	0+#
¹⁷²Gd	64	108	171.96461(32)#	163+113 −99 ms^[7]	β⁻, n? (<50%)^[7]	¹⁷¹Tb	0+#
¹⁷³Gd^[8]	64	109		>310 ns
This table header & footer: view

[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]
# – 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 or EC to ¹⁴⁸Eu
[12]
Theorized to also undergo β⁺β⁺ decay to ¹⁵⁰Sm
[13]
primordial radionuclide
[14]
Theorized to also undergo β⁺β⁺ decay to ¹⁵²Sm
[15]
Fission product
[16]
Believed to undergo α decay to ¹⁵⁰Sm
[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

As a pure alpha emitter with a half-life of 86.9±3.9 year (the same as plutonium-238 within error),^[2] gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.^[9]

Gadolinium-153

Gadolinium-153 has a half-life of 240.6 days 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.^[10] It can also detect the loss of calcium in the hip and back bones, allowing the ability to diagnose osteoporosis.^[11]

References

[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.
[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. 194 110708. Elsevier BV. 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]
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.
[6]
Suzuki, H; Fukuda, N; Takeda, H; Shimizu, Y; Yoshimoto, M; Togano, Y; Sato, H; Kitamura, N; Momota, S; Kusaka, K; Yanagisawa, Y; Ohtake, M; Fukunishi, N; Michimasa, S (3 February 2026). "Discovery of Proton-Rich Radioactive Isotopes in the Z = 63–70 Region Produced by the Projectile Fragmentation of a 345-MeV/Nucleon 238U Beam". Progress of Theoretical and Experimental Physics. 2026 (2). doi:10.1093/ptep/ptaf190.
[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]
Sumikama, Toshiyuki; Fukuda, Naoki; Kubo, Toshiyuki; Suzuki, Hiroshi; Takeda, Hiroyuki; Inabe, Naohito; Kameda, Daisuke; Ahn, Deuk Soon; Murai, Daichi; Yoshida, Koichi; Kusaka, Kensuke; Yanagisawa, Yoshiyuki; Ohtake, Masao; Shimizu, Yohei; Sato, Yuki; Sato, Hiromi; Otsu, Hideaki; Baba, Hidetada; Lorusso, Giuseppe; Söderström, Pär-Anders; Isobe, Tadaaki; Imai, Nobuaki; Mukai, Momo; Kimura, Sota; Miyatake, Hiroari; Iwasa, Naohito; Yagi, Ayumi; Yokoyama, Rin; Tarasov, Oleg Borisovich; Geissel, Hans (15 February 2026). "Expanding the Isotopic Frontier: Seven New Neutron-Rich Rare-Earth Isotopes Observed at RIKEN RI Beam Factory". Journal of the Physical Society of Japan. 95 (2). doi:10.7566/JPSJ.95.024202.
[9]
National Research Council of the National Academies; Division on Engineering Physical Sciences; Aeronautics Space Engineering Board; Space Studies Board; Radioisotope Power Systems Committee (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.
[10]
"PNNL: Isotope Sciences Program – Gadolinium-153". pnl.gov. Archived from the original on 2009-05-27.
[11]
"Gadolinium". BCIT Chemistry Resource Center. British Columbia Institute of Technology. Archived from the original on 23 August 2011. Retrieved 30 March 2011.

Isotopes of gadolinium

List of isotopes

Gadolinium-148

Gadolinium-153

See also

References

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