Naturally occurring gadolinium (₆₄Gd) is composed of 6 stable

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

s, 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 Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * ''Half Life: ...

of more than 1.3×10²¹ years has been set experimentally. 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 Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Th ...

, and the primary mode at higher atomic weights is

beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which an atomic nucleus emits a beta particle (fast energetic electron or positron), transforming into an isobar of that nuclide. For example, beta decay of a neutron ...

. 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

, -id=Gadolinium-135 , rowspan=2, ¹³⁵Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 71 , rowspan=2, 134.95250(43)# , rowspan=2, 1.1(2) s , β⁺ (98%) , ¹³⁵Eu , rowspan=2, (5/2+) , rowspan=2, , rowspan=2, , - , β⁺, p (98%) , ¹³⁴Sm , -id=Gadolinium-136 , rowspan=2, ¹³⁶Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 72 , rowspan=2, 135.94730(32)# , rowspan=2, 1# s 200 ns, β⁺? , ¹³⁶Eu , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p? , ¹³⁵Sm , -id=Gadolinium-137 , rowspan=2, ¹³⁷Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 73 , rowspan=2, 136.94502(32)# , rowspan=2, 2.2(2) s , β⁺ , ¹³⁷Eu , rowspan=2, (7/2)+# , rowspan=2, , rowspan=2, , - , β⁺, p? , ¹³⁶Sm , -id=Gadolinium-138 , ¹³⁸Gd , style="text-align:right" , 64 , style="text-align:right" , 74 , 137.94025(22)# , 4.7(9) s , β⁺ , ¹³⁸Eu , 0+ , , , -id=Gadolinium-138m , style="text-indent:1em" , ^138mGd , colspan="3" style="text-indent:2em" , 2232.6(11) keV , 6.2(0.2) μs , IT , ¹³⁸Gd , (8−) , , , -id=Gadolinium-139 , rowspan=2, ¹³⁹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 75 , rowspan=2, 138.93813(21)# , rowspan=2, 5.7(3) s , β⁺ , ¹³⁹Eu , rowspan=2, 9/2−# , rowspan=2, , rowspan=2, , - , β⁺, p? , ¹³⁸Sm , -id=Gadolinium-139m , rowspan=2 style="text-indent:1em" , ^139mGdOrder of ground state and isomer is uncertain. , rowspan=2 colspan="3" style="text-indent:2em" , 250(150)# keV , rowspan=2, 4.8(9) s , β⁺ , ¹³⁹Eu , rowspan=2, 1/2+# , rowspan=2, , rowspan=2, , - , β⁺, p? , ¹³⁸Sm , -id=Gadolinium-140 , rowspan=2, ¹⁴⁰Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 76 , rowspan=2, 139.933674(30) , rowspan=2, 15.8(4) s , β⁺ (67(8)%) , rowspan=2, ¹⁴⁰Eu , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , EC (33(8)%) , -id=Gadolinium-141 , rowspan=2, ¹⁴¹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 77 , rowspan=2, 140.932126(21) , rowspan=2, 14(4) s , β⁺ (99.97%) , ¹⁴¹Eu , rowspan=2, (1/2+) , rowspan=2, , rowspan=2, , - , β⁺, p (0.03%) , ¹⁴⁰Sm , -id=Gadolinium-141m , rowspan=2 style="text-indent:1em" , ^141mGd , rowspan=2 colspan="3" style="text-indent:2em" , 377.76(9) keV , rowspan=2, 24.5(5) s , β⁺ (89%) , ¹⁴¹Eu , rowspan=2, (11/2−) , rowspan=2, , rowspan=2, , - , IT (11%) , ¹⁴¹Gd , -id=Gadolinium-142 , rowspan=2, ¹⁴²Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 78 , rowspan=2, 141.928116(30) , rowspan=2, 70.2(6) s , EC (52(5)%) , rowspan=2, ¹⁴²Eu , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺ (48(5)%) , -id=Gadolinium-143 , rowspan=3, ¹⁴³Gd , rowspan=3 style="text-align:right" , 64 , rowspan=3 style="text-align:right" , 79 , rowspan=3, 142.92675(22) , rowspan=3, 39(2) s , β⁺ , ¹⁴³Eu , rowspan=3, 1/2+ , rowspan=3, , rowspan=3, , - , β⁺, p? , ¹⁴²Sm , - , β⁺, α? , ¹³⁹Pm , -id=Gadolinium-143m , rowspan=3 style="text-indent:1em" , ^143mGd , rowspan=3 colspan="3" style="text-indent:2em" , 152.6(5) keV , rowspan=3, 110.0(14) s , β⁺ , ¹⁴³Eu , rowspan=3, 11/2− , rowspan=3, , rowspan=3, , - , β⁺, p? , ¹⁴²Sm , - , β⁺, α? , ¹³⁹Pm , -id=Gadolinium-144 , ¹⁴⁴Gd , style="text-align:right" , 64 , style="text-align:right" , 80 , 143.922963(30) , 4.47(6) min , β⁺ , ¹⁴⁴Eu , 0+ , , , -id=Gadolinium-144m , style="text-indent:1em" , ^144mGd , colspan="3" style="text-indent:2em" , 3433.1(5) keV , 145(30) ns , IT , ¹⁴⁴Gd , (10+) , , , -id=Gadolinium-145 , ¹⁴⁵Gd , style="text-align:right" , 64 , style="text-align:right" , 81 , 144.921710(21) , 23.0(4) min , β⁺ , ¹⁴⁵Eu , 1/2+ , , , -id=Gadolinium-145m , rowspan=2 style="text-indent:1em" , ^145mGd , rowspan=2 colspan="3" style="text-indent:2em" , 749.1(2) keV , rowspan=2, 85(3) s , IT (94.3%) , ¹⁴⁵Gd , rowspan=2, 11/2− , rowspan=2, , rowspan=2, , - , β⁺ (5.7%) , ¹⁴⁵Eu , -id=Gadolinium-146 , ¹⁴⁶Gd , style="text-align:right" , 64 , style="text-align:right" , 82 , 145.9183185(44) , 48.27(10) d , EC , ¹⁴⁶Eu , 0+ , , , -id=Gadolinium-147 , ¹⁴⁷Gd , style="text-align:right" , 64 , style="text-align:right" , 83 , 146.9191010(20) , 38.06(12) h , β⁺ , ¹⁴⁷Eu , 7/2− , , , -id=Gadolinium-147m , style="text-indent:1em" , ^147mGd , colspan="3" style="text-indent:2em" , 8587.8(5) keV , 510(20) ns , IT , ¹⁴⁷Gd , 49/2+ , , , - , ¹⁴⁸Gd , style="text-align:right" , 64 , style="text-align:right" , 84 , 147.9181214(16) , 86.9(39) y , αTheorized to also undergo β⁺β⁺ decay to ''¹⁴⁸Sm'' , ¹⁴⁴Sm , 0+ , , -id=Gadolinium-149 , rowspan=2, ¹⁴⁹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 85 , rowspan=2, 148.9193477(36) , rowspan=2, 9.28(10) d , β⁺ , ¹⁴⁹Eu , rowspan=2, 7/2− , rowspan=2, , rowspan=2, , - , α (4.3×10⁻⁴%) , ¹⁴⁵Sm , -id=Gadolinium-150 , ¹⁵⁰Gd , style="text-align:right" , 64 , style="text-align:right" , 86 , 149.9186639(65) , 1.79(8)×10⁶ y , αTheorized to also undergo β⁺β⁺ decay to ¹⁵⁰Sm , ¹⁴⁶Sm , 0+ , , , -id=Gadolinium-151 , rowspan=2, ¹⁵¹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 87 , rowspan=2, 150.9203549(32) , rowspan=2, 123.9(10) d , EC , ''¹⁵¹Eu'' , rowspan=2, 7/2− , rowspan=2, , rowspan=2, , - , α (1.1×10⁻⁶%) , ''¹⁴⁷Sm'' , -id=Gadolinium-152 , ¹⁵²Gd primordial radionuclide , style="text-align:right" , 64 , style="text-align:right" , 88 , 151.9197984(11) , 1.08(8)×10¹⁴ y , αTheorized to also undergo β⁺β⁺ decay to ¹⁵²Sm , ''¹⁴⁸Sm'' , 0+ , 0.0020(1) , , - , ¹⁵³Gd , style="text-align:right" , 64 , style="text-align:right" , 89 , 152.9217569(11) , 240.6(7) d , EC , ¹⁵³Eu , 3/2− , , , -id=Gadolinium-153m1 , style="text-indent:1em" , ^153m1Gd , colspan="3" style="text-indent:2em" , 95.1737(8) keV , 3.5(4) μs , IT , ¹⁵³Gd , 9/2+ , , , -id=Gadolinium-153m2 , style="text-indent:1em" , ^153m2Gd , colspan="3" style="text-indent:2em" , 171.188(4) keV , 76.0(14) μs , IT , ¹⁵³Gd , (11/2−) , , , -id=Gadolinium-154 , ¹⁵⁴Gd , style="text-align:right" , 64 , style="text-align:right" , 90 , 153.9208730(11) , colspan="3" style="text-align:center;", Observationally StableBelieved to undergo α decay to ¹⁵⁰Sm , 0+ , 0.0218(2) , , -id=Gadolinium-155 , ¹⁵⁵Gd Fission product , style="text-align:right" , 64 , style="text-align:right" , 91 , 154.9226294(11) , colspan="3" style="text-align:center;", Observationally StableBelieved to undergo α decay to ¹⁵¹Sm , 3/2− , 0.1480(9) , , -id=Gadolinium-155m , style="text-indent:1em" , ^155mGd , colspan="3" style="text-indent:2em" , 121.10(19) keV , 31.97(27) ms , IT , ¹⁵⁵Gd , 11/2− , , , -id=Gadolinium-156 , ¹⁵⁶Gd , style="text-align:right" , 64 , style="text-align:right" , 92 , 155.9221301(11) , colspan="3" style="text-align:center;", Stable , 0+ , 0.2047(3) , , -id=Gadolinium-156m , style="text-indent:1em" , ^156mGd , colspan="3" style="text-indent:2em" , 2137.60(5) keV , 1.3(1) μs , IT , ¹⁵⁶Gd , 7- , , , -id=Gadolinium-157 , ¹⁵⁷Gd , style="text-align:right" , 64 , style="text-align:right" , 93 , 156.9239674(10) , colspan="3" style="text-align:center;", Stable , 3/2− , 0.1565(4) , , -id=Gadolinium-157m1 , style="text-indent:1em" , ^157m1Gd , colspan="3" style="text-indent:2em" , 63.916(5) keV , 460(40) ns , IT , ¹⁵⁷Gd , 5/2+ , , , -id=Gadolinium-157m2 , style="text-indent:1em" , ^157m2Gd , colspan="3" style="text-indent:2em" , 426.539(23) keV , 18.5(23) μs , IT , ¹⁵⁷Gd , 11/2− , , , -id=Gadolinium-158 , ¹⁵⁸Gd , style="text-align:right" , 64 , style="text-align:right" , 94 , 157.9241112(10) , colspan="3" style="text-align:center;", Stable , 0+ , 0.2484(8) , , -id=Gadolinium-159 , ¹⁵⁹Gd , style="text-align:right" , 64 , style="text-align:right" , 95 , 158.9263958(11) , 18.479(4) h , β⁻ , ¹⁵⁹Tb , 3/2− , , , -id=Gadolinium-160 , ¹⁶⁰Gd , style="text-align:right" , 64 , style="text-align:right" , 96 , 159.9270612(12) , colspan="3" style="text-align:center;", Observationally StableBelieved to undergo β⁻β⁻ decay to ¹⁶⁰Dy with a

over 3.1×10¹⁹ years , 0+ , 0.2186(3) , , -id=Gadolinium-161 , ¹⁶¹Gd , style="text-align:right" , 64 , style="text-align:right" , 97 , 160.9296763(16) , 3.646(3) min , β⁻ , ¹⁶¹Tb , 5/2− , , , -id=Gadolinium-162 , ¹⁶²Gd , style="text-align:right" , 64 , style="text-align:right" , 98 , 161.9309918(43) , 8.4(2) min , β⁻ , ¹⁶²Tb , 0+ , , , -id=Gadolinium-163 , ¹⁶³Gd , style="text-align:right" , 64 , style="text-align:right" , 99 , 162.93409664(86) , 68(3) s , β⁻ , ¹⁶³Tb , 7/2+ , , , -id=Gadolinium-163m , rowspan=2 style="text-indent:1em" , ^163mGd , rowspan=2 colspan="3" style="text-indent:2em" , 138.22(20) keV , rowspan=2, 23.5(10) s , IT? , ¹⁶³Gd , rowspan=2, 1/2− , rowspan=2, , rowspan=2, , - , β⁻ , ¹⁶³Tb , -id=Gadolinium-164 , ¹⁶⁴Gd , style="text-align:right" , 64 , style="text-align:right" , 100 , 163.9359162(11) , 45(3) s , β⁻ , ¹⁶⁴Tb , 0+ , , , -id=Gadolinium-164m , style="text-indent:1em" , ^164mGd , colspan="3" style="text-indent:2em" , 1095.8(4) keV , 589(18) ns , IT , ¹⁶⁴Gd , (4−) , , , -id=Gadolinium-165 , ¹⁶⁵Gd , style="text-align:right" , 64 , style="text-align:right" , 101 , 164.9393171(14) , 11.6(10) s , β⁻ , ¹⁶⁵Tb , 1/2−# , , , -id=Gadolinium-166 , ¹⁶⁶Gd , style="text-align:right" , 64 , style="text-align:right" , 102 , 165.9416304(17) , 5.1(8) s , β⁻ , ¹⁶⁶Tb , 0+ , , , -id=Gadolinium-166m , style="text-indent:1em" , ^166mGd , colspan="3" style="text-indent:2em" , 1601.5(11) keV , 950(60) ns , IT , ¹⁶⁶Gd , (6−) , , , -id=Gadolinium-167 , ¹⁶⁷Gd , style="text-align:right" , 64 , style="text-align:right" , 103 , 166.9454900(56) , 4.2(3) s , β⁻ , ¹⁶⁷Tb , 5/2−# , , , -id=Gadolinium-168 , ¹⁶⁸Gd , style="text-align:right" , 64 , style="text-align:right" , 104 , 167.94831(32)# , 3.03(16) s , β⁻ , ¹⁶⁸Tb , 0+ , , , -id=Gadolinium-169 , rowspan=2, ¹⁶⁹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 105 , rowspan=2, 168.95288(43)# , rowspan=2, 750(210) ms , β⁻ , ¹⁶⁹Tb , rowspan=2, 7/2−# , rowspan=2, , rowspan=2, , - , β⁻, n? (<0.7%) , ¹⁶⁸Tb , -id=Gadolinium-170 , rowspan=2, ¹⁷⁰Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 106 , rowspan=2, 169.95615(54)# , rowspan=2, , β⁻ , ¹⁷⁰Tb , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n? (<3%) , ¹⁶⁹Tb , -id=Gadolinium-171 , rowspan=2, ¹⁷¹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 107 , rowspan=2, 170.96113(54)# , rowspan=2, , β⁻ , ¹⁷¹Tb , rowspan=2, 9/2+# , rowspan=2, , rowspan=2, , - , β⁻, n? (<10%) , ¹⁷⁰Tb , -id=Gadolinium-172 , rowspan=2, ¹⁷²Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 108 , rowspan=2, 171.96461(32)# , rowspan=2, , β⁻ , ¹⁷²Tb , rowspan=2, 0+# , rowspan=2, , rowspan=2, , - , β⁻, n? (<50%) , ¹⁷¹Tb

Gadolinium-148

With a half-life of via alpha decay alone, gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.

Gadolinium-153

Gadolinium-153 has a half-life of and emits gamma radiation with strong peaks at 41 keV and 102 keV. It is used as a gamma ray source for

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

absorptiometry and fluorescence, for bone density gauges for

osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason f ...

screening, and for radiometric profiling in the Lixiscope portable x-ray imaging system, also known as the Lixi Profiler. In

nuclear medicine Nuclear medicine (nuclear radiology, nucleology), is a medical specialty involving the application of radioactivity, radioactive substances in the diagnosis and treatment of disease. Nuclear imaging is, in a sense, ''radiology done inside out'', ...

, it serves to calibrate the equipment needed like

single-photon emission computed tomography Single-photon emission computed tomography (SPECT, or less commonly, SPET) is a nuclear medicine tomography, tomographic imaging technique using gamma rays. It is very similar to conventional nuclear medicine planar imaging using a gamma camera ...

systems (SPECT) to make

x-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

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

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Gadolinium Gadolinium

List of isotopes

Gadolinium-148

Gadolinium-153

See also

References