Naturally occurring

gadolinium Gadolinium is a chemical element with the symbol Gd and atomic number 64. Gadolinium is a silvery-white metal when oxidation is removed. It is only slightly malleable and is a ductile rare-earth element. Gadolinium reacts with atmospheric oxygen ...

(₆₄Gd) is composed of 6 stable

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

s, ¹⁵⁴Gd, ¹⁵⁵Gd, ¹⁵⁶Gd, ¹⁵⁷Gd, ¹⁵⁸Gd and ¹⁶⁰Gd, and 1

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

, ¹⁵²Gd, with ¹⁵⁸Gd being the most abundant (24.84%

natural abundance In physics, natural abundance (NA) refers to the abundance of isotopes of a chemical element as naturally found on a planet. The relative atomic mass (a weighted average, weighted by mole-fraction abundance figures) of these isotopes is the atomi ...

). The predicted

double beta decay In nuclear physics, double beta decay is a type of radioactive decay in which two neutrons are simultaneously transformed into two protons, or vice versa, inside an atomic nucleus. As in single beta decay, this process allows the atom to move clos ...

of ¹⁶⁰Gd has never been observed; only a lower limit on its

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

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 74.7 years. The majority of these have half-lives less than 24.6 seconds. Gadolinium isotopes have 10 metastable

isomers In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of 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. Thi ...

, 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 a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...

. The primary decay products for isotopes lighter than ¹⁵⁸Gd are

isotopes of europium Naturally occurring europium (63Eu) is composed of two isotopes, 151Eu and 153Eu, with 153Eu being the most abundant (52.2% natural abundance). While 153Eu is observationally stable, 151Eu was found in 2007 to be unstable and undergo alpha decay ...

and the primary products of heavier isotopes are isotopes of terbium. Gadolinium-153 has a half-life of 240.4 ± 10 days and emits gamma radiation with strong peaks at 41

keV Kev can refer to: Given name * Kev Adams, French comedian, actor, screenwriter and film producer born Kevin Smadja in 1991 * Kevin Kev Carmody (born 1946), Indigenous Australian singer-songwriter * Kev Coghlan (born 1988), Scottish Grand Prix moto ...

and 102 keV. It is used as a gamma ray source for

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

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 Nuclear medicine or nucleology is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear imaging, in a sense, is " radiology done inside out" because it records radiation emi ...

, it serves to calibrate the equipment needed like single-photon emission computed tomography systems (SPECT) to make

x-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

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 Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

in the hip and back bones, allowing the ability to diagnose osteoporosis. Gadolinium-148 would be ideal for

radioisotope thermoelectric generators A radioisotope thermoelectric generator (RTG, RITEG), sometimes referred to as a radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert the heat released by the decay of a suitable radioact ...

due to its 74-year half-life, high density, and dominant alpha decay mode. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.

List of isotopes

, - , ¹³⁴Gd , style="text-align:right" , 64 , style="text-align:right" , 70 , 133.95537(43)# , 0.4# s , , , 0+ , , , - , ¹³⁵Gd , style="text-align:right" , 64 , style="text-align:right" , 71 , 134.95257(54)# , 1.1(2) s , , , 3/2− , , , - , ¹³⁶Gd , style="text-align:right" , 64 , style="text-align:right" , 72 , 135.94734(43)# , 1# s 200 ns, β⁺ , ¹³⁶Eu , , , , - , rowspan=2, ¹³⁷Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 73 , rowspan=2, 136.94502(43)# , rowspan=2, 2.2(2) s , β⁺ , ¹³⁷Eu , rowspan=2, 7/2+# , rowspan=2, , rowspan=2, , - , β⁺, p (rare) , ¹³⁶Sm , - , ¹³⁸Gd , style="text-align:right" , 64 , style="text-align:right" , 74 , 137.94012(21)# , 4.7(9) s , β⁺ , ¹³⁸Eu , 0+ , , , - , style="text-indent:1em" , ^138mGd , colspan="3" style="text-indent:2em" , 2232.7(11) keV , 6(1) µs , , , (8−) , , , - , rowspan=2, ¹³⁹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 75 , rowspan=2, 138.93824(21)# , rowspan=2, 5.7(3) s , β⁺ , ¹³⁹Eu , rowspan=2, 9/2−# , rowspan=2, , rowspan=2, , - , β⁺, p (rare) , ¹³⁸Sm , - , style="text-indent:1em" , ^139mGd , colspan="3" style="text-indent:2em" , 250(150)# keV , 4.8(9) s , , , 1/2+# , , , - , ¹⁴⁰Gd , style="text-align:right" , 64 , style="text-align:right" , 76 , 139.93367(3) , 15.8(4) s , β⁺ , ¹⁴⁰Eu , 0+ , , , - , 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 (.03%) , ¹⁴⁰Sm , - , rowspan=2 style="text-indent:1em" , ^141mGd , rowspan=2 colspan="3" style="text-indent:2em" , 377.8(2) keV , rowspan=2, 24.5(5) s , β⁺ (89%) , ¹⁴¹Eu , rowspan=2, (11/2−) , rowspan=2, , rowspan=2, , - , IT (11%) , ¹⁴¹Gd , - , ¹⁴²Gd , style="text-align:right" , 64 , style="text-align:right" , 78 , 141.92812(3) , 70.2(6) s , β⁺ , ¹⁴²Eu , 0+ , , , - , 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⁺, α (rare) , ¹³⁹Pm , - , β⁺, p (rare) , ¹⁴²Sm , - , 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⁺, α (rare) , ¹³⁹Pm , - , β⁺, p (rare) , ¹⁴²Sm , - , ¹⁴⁴Gd , style="text-align:right" , 64 , style="text-align:right" , 80 , 143.92296(3) , 4.47(6) min , β⁺ , ¹⁴⁴Eu , 0+ , , , - , ¹⁴⁵Gd , style="text-align:right" , 64 , style="text-align:right" , 81 , 144.921709(20) , 23.0(4) min , β⁺ , ¹⁴⁵Eu , 1/2+ , , , - , 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 , - , ¹⁴⁶Gd , style="text-align:right" , 64 , style="text-align:right" , 82 , 145.918311(5) , 48.27(10) d , EC , ¹⁴⁶Eu , 0+ , , , - , ¹⁴⁷Gd , style="text-align:right" , 64 , style="text-align:right" , 83 , 146.919094(3) , 38.06(12) h , β⁺ , ¹⁴⁷Eu , 7/2− , , , - , style="text-indent:1em" , ^147mGd , colspan="3" style="text-indent:2em" , 8587.8(4) keV , 510(20) ns , , , (49/2+) , , , - , rowspan=2, ¹⁴⁸Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 84 , rowspan=2, 147.918115(3) , rowspan=2, 74.6(30) y , α , ¹⁴⁴Sm , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺β⁺ (rare) , ''¹⁴⁸Sm'' , - , rowspan=2, ¹⁴⁹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 85 , rowspan=2, 148.919341(4) , rowspan=2, 9.28(10) d , β⁺ , ¹⁴⁹Eu , rowspan=2, 7/2− , rowspan=2, , rowspan=2, , - , α (4.34×10⁻⁴%) , ¹⁴⁵Sm , - , rowspan=2, ¹⁵⁰Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 86 , rowspan=2, 149.918659(7) , rowspan=2, 1.79(8)×10⁶ y , α , ¹⁴⁶Sm , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺β⁺ (rare) , ¹⁵⁰Sm , - , rowspan=2, ¹⁵¹Gd , rowspan=2 style="text-align:right" , 64 , rowspan=2 style="text-align:right" , 87 , rowspan=2, 150.920348(4) , rowspan=2, 124(1) d , EC , ''¹⁵¹Eu'' , rowspan=2, 7/2− , rowspan=2, , rowspan=2, , - , α (10⁻⁶%) , ''¹⁴⁷Sm'' , - , ¹⁵²Gd primordial radionuclide , style="text-align:right" , 64 , style="text-align:right" , 88 , 151.9197910(27) , 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 , 152.9217495(27) , 240.4(10) d , EC , ¹⁵³Eu , 3/2− , , , - , style="text-indent:1em" , ^153m1Gd , colspan="3" style="text-indent:2em" , 95.1737(12) keV , 3.5(4) µs , , , (9/2+) , , , - , style="text-indent:1em" , ^153m2Gd , colspan="3" style="text-indent:2em" , 171.189(5) keV , 76.0(14) µs , , , (11/2−) , , , - , ¹⁵⁴Gd , style="text-align:right" , 64 , style="text-align:right" , 90 , 153.9208656(27) , colspan="3" style="text-align:center;",

Observationally Stable Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes. Th ...

Believed to undergo α decay to ¹⁵⁰Sm , 0+ , 0.0218(3) , , - , ¹⁵⁵Gd Fission product , style="text-align:right" , 64 , style="text-align:right" , 91 , 154.9226220(27) , colspan="3" style="text-align:center;", Observationally StableBelieved to undergo α decay to ¹⁵¹Sm , 3/2− , 0.1480(12) , , - , style="text-indent:1em" , ^155mGd , colspan="3" style="text-indent:2em" , 121.05(19) keV , 31.97(27) ms , IT , ¹⁵⁵Gd , 11/2− , , , - , ¹⁵⁶Gd , style="text-align:right" , 64 , style="text-align:right" , 92 , 155.9221227(27) , colspan="3" style="text-align:center;", StableTheoretically capable of spontaneous fission , 0+ , 0.2047(9) , , - , style="text-indent:1em" , ^156mGd , colspan="3" style="text-indent:2em" , 2137.60(5) keV , 1.3(1) µs , , , 7- , , , - , ¹⁵⁷Gd , style="text-align:right" , 64 , style="text-align:right" , 93 , 156.9239601(27) , colspan="3" style="text-align:center;", Stable , 3/2− , 0.1565(2) , , - , ¹⁵⁸Gd , style="text-align:right" , 64 , style="text-align:right" , 94 , 157.9241039(27) , colspan="3" style="text-align:center;", Stable , 0+ , 0.2484(7) , , - , ¹⁵⁹Gd , style="text-align:right" , 64 , style="text-align:right" , 95 , 158.9263887(27) , 18.479(4) h , β⁻ , ¹⁵⁹Tb , 3/2− , , , - , ¹⁶⁰Gd , style="text-align:right" , 64 , style="text-align:right" , 96 , 159.9270541(27) , colspan="3" style="text-align:center;", Observationally StableBelieved to undergo β⁻β⁻ decay to ¹⁶⁰Dy with a

over 1.3×10²¹ years , 0+ , 0.2186(19) , , - , ¹⁶¹Gd , style="text-align:right" , 64 , style="text-align:right" , 97 , 160.9296692(29) , 3.646(3) min , β⁻ , ¹⁶¹Tb , 5/2− , , , - , ¹⁶²Gd , style="text-align:right" , 64 , style="text-align:right" , 98 , 161.930985(5) , 8.4(2) min , β⁻ , ¹⁶²Tb , 0+ , , , - , ¹⁶³Gd , style="text-align:right" , 64 , style="text-align:right" , 99 , 162.93399(32)# , 68(3) s , β⁻ , ¹⁶³Tb , 7/2+# , , , - , ¹⁶⁴Gd , style="text-align:right" , 64 , style="text-align:right" , 100 , 163.93586(43)# , 45(3) s , β⁻ , ¹⁶⁴Tb , 0+ , , , - , ¹⁶⁵Gd , style="text-align:right" , 64 , style="text-align:right" , 101 , 164.93938(54)# , 10.3(16) s , β⁻ , ¹⁶⁵Tb , 1/2−# , , , - , ¹⁶⁶Gd , style="text-align:right" , 64 , style="text-align:right" , 102 , 165.94160(64)# , 4.8(10) s , β⁻ , ¹⁶⁶Tb , 0+ , , , - , ¹⁶⁷Gd , style="text-align:right" , 64 , style="text-align:right" , 103 , 166.94557(64)# , 4.2(3) s , β⁻ , ¹⁶⁷Tb , 5/2−# , , , - , ¹⁶⁸Gd , style="text-align:right" , 64 , style="text-align:right" , 104 , 167.94836(75)# , 3.03(16) s , β⁻ , ¹⁶⁸Tb , 0+ , , , - , ¹⁶⁹Gd , style="text-align:right" , 64 , style="text-align:right" , 105 , 168.95287(86)# , 750(210) ms , β⁻ , ¹⁶⁹Tb , 7/2−# , , , - , ¹⁷⁰Gd , style="text-align:right" , 64 , style="text-align:right" , 106 , , , β⁻ , ¹⁷⁰Tb , 0+ , , , - , ¹⁷¹Gd , style="text-align:right" , 64 , style="text-align:right" , 107 , , , β⁻ , ¹⁷¹Tb , , , , - , ¹⁷²Gd , style="text-align:right" , 64 , style="text-align:right" , 108 , , , β⁻ , ¹⁷²Tb , 0+ , ,

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 Gadolinium is a chemical element with the symbol Gd and atomic number 64. Gadolinium is a silvery-white metal when oxidation is removed. It is only slightly malleable and is a ductile rare-earth element. Gadolinium reacts with atmospheric oxygen ...