Isotopes Of Gadolinium

Main isotopes of Chemistry:gadolinium (₆₄Gd)
γ	–
Standard atomic weight Ar, standard(Gd)	157.25(3);
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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.

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

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)
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
¹³³Gd^[2]	64	69	132.96129(54)#	2026	10# ms [>310 ns]			5/2+#
¹³⁴Gd^[2]	64	70	133.95542(43)#	2026	400# ms [>310 ns]			0+
¹³⁵Gd	64	71	134.95250(43)#	1996	1.1(2) s	β⁺ (98%)	¹³⁵Eu	(5/2+)
¹³⁵Gd	64	71	134.95250(43)#	1996	1.1(2) s	β⁺, p (98%)	¹³⁴Sm	(5/2+)
¹³⁶Gd^[2]	64	72	135.94730(32)#	2026	1# s [>310 ns]	β⁺?	¹³⁶Eu	0+
¹³⁶Gd^[2]	64	72	135.94730(32)#	2026	1# s [>310 ns]	β⁺, p?	¹³⁵Sm	0+
¹³⁷Gd	64	73	136.94502(32)#	1999	2.2(2) s	β⁺	¹³⁷Eu	(7/2)+#
¹³⁷Gd	64	73	136.94502(32)#	1999	2.2(2) s	β⁺, p?	¹³⁶Sm	(7/2)+#
¹³⁸Gd	64	74	137.94025(22)#	1985	4.7(9) s	β⁺	¹³⁸Eu	0+
^138mGd	2232.6(11) keV			1997	6.2(0.2) μs	IT	¹³⁸Gd	(8−)
¹³⁹Gd	64	75	138.93813(21)#	1983	5.7(3) s	β⁺	¹³⁹Eu	9/2−#
¹³⁹Gd	64	75	138.93813(21)#	1983	5.7(3) s	β⁺, p?	¹³⁸Sm	9/2−#
^139mGd^{[n 10]}	250(150)# keV			1999	4.8(9) s	β⁺	¹³⁹Eu	1/2+#
^139mGd^{[n 10]}	250(150)# keV			1999	4.8(9) s	β⁺, p?	¹³⁸Sm	1/2+#
¹⁴⁰Gd	64	76	139.933674(30)	1985	15.8(4) s	β⁺ (67(8)%)	¹⁴⁰Eu	0+
¹⁴⁰Gd	64	76	139.933674(30)	1985	15.8(4) s	EC (33(8)%)	¹⁴⁰Eu	0+
¹⁴¹Gd	64	77	140.932126(21)	1986	14(4) s	β⁺ (99.97%)	¹⁴¹Eu	(1/2+)
¹⁴¹Gd	64	77	140.932126(21)	1986	14(4) s	β⁺, p (0.03%)	¹⁴⁰Sm	(1/2+)
^141mGd	377.76(9) keV			1989	24.5(5) s	β⁺ (89%)	¹⁴¹Eu	(11/2−)
^141mGd	377.76(9) keV			1989	24.5(5) s	IT (11%)	¹⁴¹Gd	(11/2−)
¹⁴²Gd	64	78	141.928116(30)	1986	70.2(6) s	EC (52(5)%)	¹⁴²Eu	0+
¹⁴²Gd	64	78	141.928116(30)	1986	70.2(6) s	β⁺ (48(5)%)	¹⁴²Eu	0+
¹⁴³Gd	64	79	142.92675(22)	1975	39(2) s	β⁺	¹⁴³Eu	1/2+
						β⁺, p?	¹⁴²Sm
						β⁺, α?	¹³⁹Pm
^143mGd	152.6(5) keV			1975	110.0(14) s	β⁺	¹⁴³Eu	11/2−
						β⁺, p?	¹⁴²Sm
						β⁺, α?	¹³⁹Pm
¹⁴⁴Gd	64	80	143.922963(30)	1968	4.47(6) min	β⁺	¹⁴⁴Eu	0+
^144mGd	3433.1(5) keV			1978	145(30) ns	IT	¹⁴⁴Gd	(10+)
¹⁴⁵Gd	64	81	144.921710(21)	1959	23.0(4) min	β⁺	¹⁴⁵Eu	1/2+
^145mGd	749.1(2) keV			1969	85(3) s	IT (94.3%)	¹⁴⁵Gd	11/2−
^145mGd	749.1(2) keV			1969	85(3) s	β⁺ (5.7%)	¹⁴⁵Eu	11/2−
¹⁴⁶Gd	64	82	145.9183185(44)	1957	48.27(9) d	EC	¹⁴⁶Eu	0+
¹⁴⁷Gd	64	83	146.9191010(20)	1957	38.06(12) h	β⁺	¹⁴⁷Eu	7/2−
^147mGd	8587.8(5) keV			1978	510(20) ns	IT	¹⁴⁷Gd	49/2+
¹⁴⁸Gd	64	84	147.9181214(16)	1953	86.9(39) y^[3]	α^{[n 11]}	¹⁴⁴Sm	0+
¹⁴⁹Gd	64	85	148.9193477(36)	1951	9.28(10) d	β⁺	¹⁴⁹Eu	7/2−
¹⁴⁹Gd	64	85	148.9193477(36)	1951	9.28(10) d	α (4.3×10⁻⁴%)	¹⁴⁵Sm	7/2−
¹⁵⁰Gd	64	86	149.9186639(65)	1953	1.79(8)×10⁶ y	α^{[n 12]}	¹⁴⁶Sm	0+
¹⁵¹Gd	64	87	150.9203549(32)	1950	123.9(10) d	EC	¹⁵¹Eu	7/2−
¹⁵¹Gd	64	87	150.9203549(32)	1950	123.9(10) d	α (1.1×10⁻⁶%)	¹⁴⁷Sm	7/2−
¹⁵²Gd^{[n 13]}	64	88	151.9197984(11)	1938	1.08(8)×10¹⁴ y	α^{[n 14]}	¹⁴⁸Sm	0+	0.0020(1)
¹⁵³Gd	64	89	152.9217569(11)	1947	240.6(7) d	EC	¹⁵³Eu	3/2−
^153m1Gd	95.1737(8) keV			1979	3.5(4) μs	IT	¹⁵³Gd	9/2+
^153m2Gd	171.188(4) keV			1967	76.0(14) μs	IT	¹⁵³Gd	(11/2−)
¹⁵⁴Gd^{[n 15]}	64	90	153.9208730(11)	1938	Observationally Stable^{[n 16]}			0+	0.0218(2)
¹⁵⁵Gd^{[n 15]}	64	91	154.9226294(11)	1933	Observationally Stable^{[n 17]}			3/2−	0.1480(9)
^155mGd	121.10(19) keV			1967	31.97(27) ms	IT	¹⁵⁵Gd	11/2−
¹⁵⁶Gd^{[n 15]}	64	92	155.9221301(11)	1933	Stable			0+	0.2047(3)
^156mGd	2137.60(5) keV			1969	1.3(1) μs	IT	¹⁵⁶Gd	7-
¹⁵⁷Gd^{[n 15]}	64	93	156.9239674(10)	1933	Stable			3/2−	0.1565(4)
^157m1Gd	63.916(5) keV			1964	460(40) ns	IT	¹⁵⁷Gd	5/2+
^157m2Gd	426.539(23) keV			1967	18.5(23) μs	IT	¹⁵⁷Gd	11/2−
¹⁵⁸Gd^{[n 15]}	64	94	157.9241112(10)	1933	Stable			0+	0.2484(8)
¹⁵⁹Gd^{[n 15]}	64	95	158.9263958(11)	1949	18.479(4) h	β⁻	¹⁵⁹Tb	3/2−
¹⁶⁰Gd^{[n 15]}	64	96	159.9270612(12)	1933	Observationally Stable^{[n 18]}			0+	0.2186(3)
¹⁶¹Gd	64	97	160.9296763(16)	1949	3.646(3) min	β⁻	¹⁶¹Tb	5/2−
¹⁶²Gd	64	98	161.9309918(43)	1967	8.4(2) min	β⁻	¹⁶²Tb	0+
¹⁶³Gd	64	99	162.93409664(86)	1982	68(3) s	β⁻	¹⁶³Tb	7/2+
^163mGd	138.22(20) keV			2014	23.5(10) s	IT?	¹⁶³Gd	1/2−
^163mGd	138.22(20) keV			2014	23.5(10) s	β⁻	¹⁶³Tb	1/2−
¹⁶⁴Gd	64	100	163.9359162(11)	1988	45(3) s	β⁻	¹⁶⁴Tb	0+
^164mGd	1095.8(4) keV			2017	589(18) ns	IT	¹⁶⁴Gd	(4−)
¹⁶⁵Gd	64	101	164.9393171(14)	1998	11.6(10) s	β⁻	¹⁶⁵Tb	1/2−#
¹⁶⁶Gd	64	102	165.9416304(17)	2005	5.1(8) s	β⁻	¹⁶⁶Tb	0+
^166mGd	1601.5(11) keV			2014	950(60) ns	IT	¹⁶⁶Gd	(6−)
¹⁶⁷Gd	64	103	166.9454900(56)	2012	4.2(3) s	β⁻	¹⁶⁷Tb	5/2−#
¹⁶⁸Gd	64	104	167.94831(32)#	2012	3.03(16) s	β⁻	¹⁶⁸Tb	0+
¹⁶⁹Gd	64	105	168.95288(43)#	2012	750(210) ms	β⁻	¹⁶⁹Tb	7/2−#
¹⁶⁹Gd	64	105	168.95288(43)#	2012	750(210) ms	β⁻, n? (<0.7%)^[4]	¹⁶⁸Tb	7/2−#
¹⁷⁰Gd	64	106	169.95615(54)#	2012	675+94 −75 ms^[4]	β⁻	¹⁷⁰Tb	0+
¹⁷⁰Gd	64	106	169.95615(54)#	2012	675+94 −75 ms^[4]	β⁻, n? (<3%)^[4]	¹⁶⁹Tb	0+
¹⁷¹Gd	64	107	170.96113(54)#	2018	392+145 −136 ms^[4]	β⁻	¹⁷¹Tb	9/2+#
¹⁷¹Gd	64	107	170.96113(54)#	2018	392+145 −136 ms^[4]	β⁻, n? (<10%)^[4]	¹⁷⁰Tb	9/2+#
¹⁷²Gd	64	108	171.96461(32)#	2022	163+113 −99 ms^[4]	β⁻	¹⁷²Tb	0+#
¹⁷²Gd	64	108	171.96461(32)#	2022	163+113 −99 ms^[4]	β⁻, n? (<50%)^[4]	¹⁷¹Tb	0+#
¹⁷³Gd^[5]	64	109		2026	>310 ns

↑ ^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.
↑ ^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).
↑ 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.
↑ Order of ground state and isomer is uncertain.
↑ Theorized to also undergo β⁺β⁺ decay to ¹⁴⁸Sm or EC to ¹⁴⁸Eu
↑ Theorized to also undergo β⁺β⁺ decay to ¹⁵⁰Sm
↑ primordial radionuclide
↑ Theorized to also undergo β⁺β⁺ decay to ¹⁵²Sm
↑ ^15.0 ^15.1 ^15.2 ^15.3 ^15.4 ^15.5 ^15.6 Fission product
↑ Believed to undergo α decay to ¹⁵⁰Sm
↑ Believed to undergo α decay to ¹⁵¹Sm
↑ 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 years (the same as plutonium-238 within error),^[3] gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.^[6]

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.^[7] It can also detect the loss of calcium in the hip and back bones, allowing the ability to diagnose osteoporosis.^[8]

References

↑ 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.
↑ ^2.0 ^2.1 ^2.2 Suzuki, H; Fukuda, N; Takeda, H; Shimizu, Y; Yoshimoto, M; Togano, Y; Sato, H; Kitamura, N et al. (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.
↑ ^3.0 ^3.1 Cite error: Invalid <ref> tag; no text was provided for refs named 148Gd
↑ ^4.0 ^4.1 ^4.2 ^4.3 ^4.4 ^4.5 ^4.6 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.
↑ Sumikama, Toshiyuki; Fukuda, Naoki; Kubo, Toshiyuki; Suzuki, Hiroshi; Takeda, Hiroyuki; Inabe, Naohito; Kameda, Daisuke; Ahn, Deuk Soon et al. (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.
↑ 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. doi:10.17226/12653. ISBN 978-0-309-13857-4.
↑ "PNNL: Isotope Sciences Program – Gadolinium-153". pnl.gov. http://radioisotopes.pnl.gov/gadolinium.stm.
↑ "Gadolinium". BCIT Chemistry Resource Center. British Columbia Institute of Technology. http://nobel.scas.bcit.ca/resource/ptable/gd.htm.

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[2] Gd – Excited nuclear isomer.

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

[TMS-4] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

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

[TNN-6] 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).

[7] Modes of decay:

EC: Electron capture

IT: Isomeric transition

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

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

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

[order-12] Order of ground state and isomer is uncertain.

[14] Theorized to also undergo β⁺β⁺ decay to ¹⁴⁸Sm or EC to ¹⁴⁸Eu

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

[16] rimordial radionuclide

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

[FP-18] 15.0 ^15.1 ^15.2 ^15.3 ^15.4 ^15.5 ^15.6 Fission product

[19] Believed to undergo α decay to ¹⁵⁰Sm

[20] Believed to undergo α decay to ¹⁵¹Sm

[21] Believed to undergo β⁻β⁻ decay to ¹⁶⁰Dy with a half-life over 3.1×10¹⁹ years

[CIAAW2013-1] 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.

[suzuki2026-11] 2.0 ^2.1 ^2.2 Suzuki, H; Fukuda, N; Takeda, H; Shimizu, Y; Yoshimoto, M; Togano, Y; Sato, H; Kitamura, N et al. (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.

[148Gd-13] 3.0 ^3.1 Cite error: Invalid <ref> tag; no text was provided for refs named 148Gd

[Ln922-22] 4.0 ^4.1 ^4.2 ^4.3 ^4.4 ^4.5 ^4.6 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.

[sumikama2026-23] Sumikama, Toshiyuki; Fukuda, Naoki; Kubo, Toshiyuki; Suzuki, Hiroshi; Takeda, Hiroyuki; Inabe, Naohito; Kameda, Daisuke; Ahn, Deuk Soon et al. (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.

[24] 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. doi:10.17226/12653. ISBN 978-0-309-13857-4.

[25] "PNNL: Isotope Sciences Program – Gadolinium-153". pnl.gov. http://radioisotopes.pnl.gov/gadolinium.stm.

[26] "Gadolinium". BCIT Chemistry Resource Center. British Columbia Institute of Technology. http://nobel.scas.bcit.ca/resource/ptable/gd.htm.

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Isotopes Of Gadolinium

Contents

List of isotopes

Gadolinium-148

Gadolinium-153

See also

References