Isotopes of terbium
Encyclopedia
Naturally occurring terbium
(Tb) is composed of 1 stable isotope
, 159Tb. 36 radioisotopes have been characterized, with the most stable being 158Tb with a half-life
of 180 years, 157Tb with a half-life of 71 years, and 160Tb with a half-life of 72.3 days. All of the remaining radioactive isotopes have half-lives that are less than 6.907 days, and the majority of these have half-lives that are less than 24 seconds. This element also has 27 meta states, with the most stable being 156m1Tb (t½ 24.4 hours), 154m2Tb (t½ 22.7 hours) and 154m1Tb (t½ 9.4 hours).
The primary decay mode before the most abundant stable isotope, 159Tb, is electron capture
, and the primary mode behind is beta minus decay. The primary decay product
s before 159Tb are element Gd (gadolinium
) isotopes, and the primary products behind are element Dy (dysprosium
) isotopes.
Standard atomic mass: 158.92535(2) u
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...
(Tb) is composed of 1 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...
, 159Tb. 36 radioisotopes have been characterized, with the most stable being 158Tb 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...
of 180 years, 157Tb with a half-life of 71 years, and 160Tb with a half-life of 72.3 days. All of the remaining radioactive isotopes have half-lives that are less than 6.907 days, and the majority of these have half-lives that are less than 24 seconds. This element also has 27 meta states, with the most stable being 156m1Tb (t½ 24.4 hours), 154m2Tb (t½ 22.7 hours) and 154m1Tb (t½ 9.4 hours).
The primary decay mode before the most abundant stable isotope, 159Tb, 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 behind is beta minus decay. 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 before 159Tb are element Gd (gadolinium
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...
) isotopes, and the primary products behind are element Dy (dysprosium
Dysprosium
Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime...
) isotopes.
Standard atomic mass: 158.92535(2) 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-life | 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 |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|
| excitation energy | |||||||||
| 135Tb | 65 | 70 | 0.94(+33-22) ms | (7/2-) | |||||
| 136Tb | 65 | 71 | 135.96138(64)# | 0.2# s | |||||
| 137Tb | 65 | 72 | 136.95598(64)# | 600# ms | 11/2-# | ||||
| 138Tb | 65 | 73 | 137.95316(43)# | 800# ms [>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... |
138Gd | |||
| 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... |
137Gd | ||||||||
| 139Tb | 65 | 74 | 138.94829(32)# | 1.6(2) s | β+ | 139Gd | 11/2-# | ||
| 140Tb | 65 | 75 | 139.94581(86) | 2.4(2) s | β+ (99.74%) | 140Gd | 5 | ||
| β+, p (.26%) | 139Eu | ||||||||
| 141Tb | 65 | 76 | 140.94145(11) | 3.5(2) s | β+ | 141Gd | (5/2-) | ||
| 141mTb | 0(200)# keV | 7.9(6) s | β+ | 141Gd | 11/2-# | ||||
| 142Tb | 65 | 77 | 141.93874(32)# | 597(17) ms | β+ | 142Gd | 1+ | ||
| β+, p | 141Eu | ||||||||
| 142m1Tb | 280.2(10) keV | 303(17) ms | 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.... (99.5%) |
142Tb | (5-) | ||||
| β+ (.5%) | 142Gd | ||||||||
| 142m2Tb | 621.4(11) keV | 15(4) µs | |||||||
| 143Tb | 65 | 78 | 142.93512(6) | 12(1) s | β+ | 143Gd | (11/2-) | ||
| 143mTb | 0(100)# keV | <21 s | β+ | 143Gd | 5/2+# | ||||
| 144Tb | 65 | 79 | 143.93305(3) | ~1 s | β+ | 144Gd | 1+ | ||
| β+, p (rare) | 143Eu | ||||||||
| 144m1Tb | 396.9(5) keV | 4.25(15) s | IT (66%) | 144Tb | (6-) | ||||
| β+ (34%) | 144Gd | ||||||||
| β+, p (<1%) | 143Eu | ||||||||
| 144m2Tb | 476.2(5) keV | 2.8(3) µs | (8-) | ||||||
| 144m3Tb | 517.1(5) keV | 670(60) ns | (9+) | ||||||
| 144m4Tb | 544.5(6) keV | <300 ns | (10+) | ||||||
| 145Tb | 65 | 80 | 144.92927(6) | 20# min | β+ | 145Gd | (3/2+) | ||
| 145mTb | 0(100)# keV | 30.9(7) s | β+ | 145Gd | (11/2-) | ||||
| 146Tb | 65 | 81 | 145.92725(5) | 8(4) s | β+ | 146Gd | 1+ | ||
| 146m1Tb | 150(100)# keV | 24.1(5) s | β+ | 146Gd | 5- | ||||
| 146m2Tb | 930(100)# keV | 1.18(2) ms | (10+) | ||||||
| 147Tb | 65 | 82 | 146.924045(13) | 1.64(3) h | β+ | 147Gd | 1/2+# | ||
| 147mTb | 50.6(9) keV | 1.87(5) min | β+ | 147Gd | (11/2)- | ||||
| 148Tb | 65 | 83 | 147.924272(15) | 60(1) min | β+ | 148Gd | 2- | ||
| 148m1Tb | 90.1(3) keV | 2.20(5) min | β+ | 148Gd | (9)+ | ||||
| 148m2Tb | 8618.6(10) keV | 1.310(7) µs | (27+) | ||||||
| 149Tb | 65 | 84 | 148.923246(5) | 4.118(25) h | β+ (83.3%) | 149Gd | 1/2+ | ||
| 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... (16.7%) |
145Eu | ||||||||
| 149mTb | 35.78(13) keV | 4.16(4) min | β+ (99.97%) | 149Gd | 11/2- | ||||
| α (.022%) | 145Eu | ||||||||
| 150Tb | 65 | 85 | 149.923660(8) | 3.48(16) h | β+ (99.95%) | 150Gd | (2-) | ||
| α (.05%) | 146Eu | ||||||||
| 150mTb | 457(29) keV | 5.8(2) min | β+ | 150Gd | 9+ | ||||
| IT (rare) | 150Tb | ||||||||
| 151Tb | 65 | 86 | 150.923103(5) | 17.609(1) h | β+ (99.99%) | 151Gd | 1/2(+) | ||
| α (.0095%) | 147Eu | ||||||||
| 151mTb | 99.54(6) keV | 25(3) s | IT (93.8%) | 151Tb | (11/2-) | ||||
| β+ (6.2%) | 151Gd | ||||||||
| 152Tb | 65 | 87 | 151.92407(4) | 17.5(1) h | β+ | 152Gd | 2- | ||
| α (7×10−7%) | 148Eu | ||||||||
| 152m1Tb | 342.15(16) keV | 0.96 µs | 5- | ||||||
| 152m2Tb | 501.74(19) keV | 4.2(1) min | IT (78.8%) | 152Tb | 8+ | ||||
| β+ (21.2%) | 152Gd | ||||||||
| 153Tb | 65 | 88 | 152.923435(5) | 2.34(1) d | β+ | 153Gd | 5/2+ | ||
| 153mTb | 163.175(5) keV | 186(4) µs | 11/2- | ||||||
| 154Tb | 65 | 89 | 153.92468(5) | 21.5(4) h | β+ (99.9%) | 154Gd | 0(+#) | ||
| β- (.1%) | 154Dy | ||||||||
| 154m1Tb | 12(7) keV | 9.4(4) h | β+ (78.2%) | 154Gd | 3- | ||||
| IT (21.8%) | 154Tb | ||||||||
| β- (.1%) | 154Dy | ||||||||
| 154m2Tb | 200(150)# keV | 22.7(5) h | 7- | ||||||
| 154m3Tb | 0+Z keV | 513(42) ns | |||||||
| 155Tb | 65 | 90 | 154.923505(13) | 5.32(6) 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... |
155Gd | 3/2+ | ||
| 156Tb | 65 | 91 | 155.924747(5) | 5.35(10) d | β+ | 156Gd | 3- | ||
| β- (rare) | 156Dy | ||||||||
| 156m1Tb | 54(3) keV | 24.4(10) h | IT | 156Tb | (7-) | ||||
| 156m2Tb | 88.4(2) keV | 5.3(2) h | (0+) | ||||||
| 157Tb | 65 | 92 | 156.9240246(27) | 71(7) a | EC | 157Gd | 3/2+ | ||
| 158Tb | 65 | 93 | 157.9254131(28) | 180(11) a | β+ (83.4%) | 158Gd | 3- | ||
| β- (16.6%) | 158Dy | ||||||||
| 158m1Tb | 110.3(12) keV | 10.70(17) s | IT (99.39%) | 158Tb | 0- | ||||
| β- (.6%) | 158Dy | ||||||||
| β+ (.01%) | 158Gd | ||||||||
| 158m2Tb | 388.37(15) keV | 0.40(4) ms | 7- | ||||||
| 159TbFission 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... |
65 | 94 | 158.9253468(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... |
3/2+ | 1.0000 | |||
| 160Tb | 65 | 95 | 159.9271676(27) | 72.3(2) d | β- | 160Dy | 3- | ||
| 161Tb | 65 | 96 | 160.9275699(28) | 6.906(19) d | β- | 161Dy | 3/2+ | ||
| 162Tb | 65 | 97 | 161.92949(4) | 7.60(15) min | β- | 162Dy | 1- | ||
| 163Tb | 65 | 98 | 162.930648(5) | 19.5(3) min | β- | 163Dy | 3/2+ | ||
| 164Tb | 65 | 99 | 163.93335(11) | 3.0(1) min | β- | 164Dy | (5+) | ||
| 165Tb | 65 | 100 | 164.93488(21)# | 2.11(10) min | β- | 165mDy | 3/2+# | ||
| 166Tb | 65 | 101 | 165.93799(11) | 25.6(22) s | β- | 166Dy | |||
| 167Tb | 65 | 102 | 166.94005(43)# | 19.4(27) s | β- | 167Dy | 3/2+# | ||
| 168Tb | 65 | 103 | 167.94364(54)# | 8.2(13) s | β- | 168Dy | 4-# | ||
| 169Tb | 65 | 104 | 168.94622(64)# | 2# s | β- | 169Dy | 3/2+# | ||
| 170Tb | 65 | 105 | 169.95025(75)# | 3# s | β- | 170Dy | |||
| 171Tb | 65 | 106 | 170.95330(86)# | 500# ms | β- | 171Dy | 3/2+# | ||