Isotopes of gadolinium
Encyclopedia
Naturally occurring gadolinium
(Gd) is composed of 6 stable isotope
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 lower limit on its half-life
of more than 1.3×1021 years has been set experimentally.
Thirty 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 isomer
s, with the most stable being 143mGd (T½=110 seconds), 145mGd (T½=85 seconds) and 141mGd (T½=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 product
s for isotopes of weights lower than 158Gd are the element Eu (europium
) isotopes and the primary products at higher weights are the element Tb (terbium
) isotopes.
Gadolinium-153 has a half-life of 240.4±10 days and emits gamma radiation with strong peaks at 41 keV
and 102 keV. It is used as a gamma ray source in X-ray
absorptiometry or bone density gauges for osteoporosis
screening, and in the Lixiscope portable x-ray imaging system.
Standard atomic mass: 157.25(3) u
Gadolinium
Gadolinium is a chemical element with the symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined form. Gadolinium was first detected spectroscopically in 1880 by de Marignac who separated its oxide and is credited with...
(Gd) is composed of 6 stable isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant (24.84% natural abundance
Natural abundance
In chemistry, natural abundance refers to the abundance of isotopes of a chemical element as naturally found on a planet. The relative atomic mass of these isotopes is the atomic weight listed for the element in the periodic table...
). The predicted double beta decay
Double beta decay
Double beta decay is a radioactive decay process where a nucleus releases two beta rays as a single process.In double-beta decay, two neutrons in the nucleus are converted to protons, and two electrons and two electron antineutrinos are emitted...
of 160Gd has never been observed; only lower limit on its half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of more than 1.3×1021 years has been set experimentally.
Thirty 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 isomer
Nuclear isomer
A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons . "Metastable" refers to the fact that these excited states have half-lives more than 100 to 1000 times the half-lives of the other possible excited nuclear states...
s, with the most stable being 143mGd (T½=110 seconds), 145mGd (T½=85 seconds) and 141mGd (T½=24.5 seconds).
The primary decay mode at atomic weights lower than the most abundant stable isotope, 158Gd, is electron capture
Electron capture
Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...
, and the primary mode at higher atomic weights is beta decay
Beta decay
In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...
. The primary decay product
Decay product
In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps...
s for isotopes of weights lower than 158Gd are the element Eu (europium
Europium
Europium is a chemical element with the symbol Eu and atomic number 63. It is named after the continent of Europe. It is a moderately hard silvery metal which readily oxidizes in air and water...
) isotopes and the primary products at higher weights are the element Tb (terbium
Terbium
Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife...
) isotopes.
Gadolinium-153 has a half-life of 240.4±10 days and emits gamma radiation with strong peaks at 41 keV
Kev
Kev can refer to:*Kev Hawkins, a fictional character.*Kevin, a given name occasionally shortened to "Kev".*Kiloelectronvolt, a unit of energy who symbol is "KeV".* Krefelder Eislauf-VereinKEV can refer to:...
and 102 keV. It is used as a gamma ray source in X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
absorptiometry or bone density gauges for osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
screening, and in the Lixiscope portable x-ray imaging system.
Standard atomic mass: 157.25(3) u
Table
| nuclide symbol |
Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... ) |
N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... ) |
isotopic mass (u) |
half-lifeBold for isotopes with half-lives longer than the age of the universe (nearly stable) | decay mode(s)Abbreviations: EC: Electron capture Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer.... |
daughter isotope(s)Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe Age of the universe The age of the universe is the time elapsed since the Big Bang posited by the most widely accepted scientific model of cosmology. The best current estimate of the age of the universe is 13.75 ± 0.13 billion years within the Lambda-CDM concordance model... ) |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|
| excitation energy | |||||||||
| 134Gd | 64 | 70 | 133.95537(43)# | 0.4# s | 0+ | ||||
| 135Gd | 64 | 71 | 134.95257(54)# | 1.1(2) s | 3/2- | ||||
| 136Gd | 64 | 72 | 135.94734(43)# | 1# s [>200 ns] | β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a... |
136Eu | |||
| 137Gd | 64 | 73 | 136.94502(43)# | 2.2(2) s | β+ | 137Eu | 7/2+# | ||
| β+, p Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very... (rare) |
136Sm | ||||||||
| 138Gd | 64 | 74 | 137.94012(21)# | 4.7(9) s | β+ | 138Eu | 0+ | ||
| 138mGd | 2232.7(11) keV | 6(1) µs | (8-) | ||||||
| 139Gd | 64 | 75 | 138.93824(21)# | 5.7(3) s | β+ | 139Eu | 9/2-# | ||
| β+, p (rare) | 138Sm | ||||||||
| 139mGd | 250(150)# keV | 4.8(9) s | 1/2+# | ||||||
| 140Gd | 64 | 76 | 139.93367(3) | 15.8(4) s | β+ | 140Eu | 0+ | ||
| 141Gd | 64 | 77 | 140.932126(21) | 14(4) s | β+ (99.97%) | 141Eu | (1/2+) | ||
| β+, p (.03%) | 140Sm | ||||||||
| 141mGd | 377.8(2) keV | 24.5(5) s | β+ (89%) | 141Eu | (11/2-) | ||||
| IT Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer.... (11%) |
141Gd | ||||||||
| 142Gd | 64 | 78 | 141.92812(3) | 70.2(6) s | β+ | 142Eu | 0+ | ||
| 143Gd | 64 | 79 | 142.92675(22) | 39(2) s | β+ | 143Eu | (1/2)+ | ||
| β+, α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less... (rare) |
139Pm | ||||||||
| β+, p (rare) | 142Sm | ||||||||
| 143mGd | 152.6(5) keV | 110.0(14) s | β+ | 143Eu | (11/2-) | ||||
| β+, α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less... (rare) |
139Pm | ||||||||
| β+, p (rare) | 142Sm | ||||||||
| 144Gd | 64 | 80 | 143.92296(3) | 4.47(6) min | β+ | 144Eu | 0+ | ||
| 145Gd | 64 | 81 | 144.921709(20) | 23.0(4) min | β+ | 145Eu | 1/2+ | ||
| 145mGd | 749.1(2) keV | 85(3) s | IT (94.3%) | 145Gd | 11/2- | ||||
| β+ (5.7%) | 145Eu | ||||||||
| 146Gd | 64 | 82 | 145.918311(5) | 48.27(10) d | EC Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... |
146Eu | 0+ | ||
| 147Gd | 64 | 83 | 146.919094(3) | 38.06(12) h | β+ | 147Eu | 7/2- | ||
| 147mGd | 8587.8(4) keV | 510(20) ns | (49/2+) | ||||||
| 148Gd | 64 | 84 | 147.918115(3) | 74.6(30) a | α | 144Sm | 0+ | ||
| β+β+ (rare) | 148Sm | ||||||||
| 149Gd | 64 | 85 | 148.919341(4) | 9.28(10) d | β+ | 149Eu | 7/2- | ||
| α (4.34×10−4%) | 145Sm | ||||||||
| 150Gd | 64 | 86 | 149.918659(7) | 1.79(8)×106 a | α | 146Sm | 0+ | ||
| β+β+ (rare) | 150Sm | ||||||||
| 151Gd | 64 | 87 | 150.920348(4) | 124(1) d | EC | 151Eu | 7/2- | ||
| α (10−6%) | 147Sm | ||||||||
| 152Gdprimordial Primordial nuclide In geochemistry and geonuclear physics, primordial nuclides or primordial isotopes are nuclides found on the earth that have existed in their current form since before Earth was formed. Only 288 such nuclides are known... radionuclide Radionuclide A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits gamma... |
64 | 88 | 151.9197910(27) | 1.08(8)×1014 a | α | 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 StableBelieved to undergo α decay to 150Sm | 0+ | 0.0218(3) | |||
| 155GdFission product Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus fissions. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons and a large release of energy in the form of heat , gamma rays and neutrinos. The... |
64 | 91 | 154.9226220(27) | Observationally StableBelieved to undergo α decay to 151Sm | 3/2- | 0.1480(12) | |||
| 155mGd | 121.05(19) keV | 31.97(27) ms | IT | 155Gd | 11/2- | ||||
| 156Gd | 64 | 92 | 155.9221227(27) | Observationally StableTheoretically capable of spontaneous fission Spontaneous fission Spontaneous fission is a form of radioactive decay characteristic of very heavy isotopes. Because the nuclear binding energy reaches a maximum at a nuclear mass greater than about 60 atomic mass units , spontaneous breakdown into smaller nuclei and single particles becomes possible at heavier masses... |
0+ | 0.2047(9) | |||
| 156mGd | 2137.60(5) keV | 1.3(1) µs | 7- | ||||||
| 157Gd | 64 | 93 | 156.9239601(27) | Observationally Stable | 3/2- | 0.1565(2) | |||
| 158Gd | 64 | 94 | 157.9241039(27) | Observationally Stable | 0+ | 0.2484(7) | |||
| 159Gd | 64 | 95 | 158.9263887(27) | 18.479(4) h | β- | 159Tb | 3/2- | ||
| 160Gd | 64 | 96 | 159.9270541(27) | Observationally StableBelieved to undergo β-β- decay to 160Dy with a half-life Half-life Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to... over 1.3×1021 years |
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)# | 3# s | β- | 167Tb | 5/2-# | ||
| 168Gd | 64 | 104 | 167.94836(75)# | 300# ms | β- | 168Tb | 0+ | ||
| 169Gd | 64 | 105 | 168.95287(86)# | 1# s | β- | 169Tb | 7/2-# | ||