Isotopes of thulium
Encyclopedia
Naturally occurring thulium
(Tm) is composed of 1 stable isotope
, 169Tm (100% natural abundance
). 34 radioisotopes have been characterized, with the most stable being 171Tm with a half-life
of 1.92 years, 170Tm with a half-life of 128.6 days, 168Tm with a half-life of 93.1 days, and 167Tm with a half-life of 9.25 days. All of the remaining radioactive isotopes have half-lives that are less than 64 hours, and the majority of these have half-lives that are less than 2 minutes. This element also has 26 meta states, with the most stable being 164mTm (t½ 5.1 minutes), 160mTm (t½ 74.5 seconds) and 155mTm (t½ 45 seconds).
The isotopes of thulium range in atomic weight
from 144.97007 u
(145Tm) to 178.95534 u (179Tm). The primary decay mode before the most abundant stable isotope, 169Tm, is electron capture
, and the primary mode after is beta emission. The primary decay product
s before 169Tm are erbium
isotopes, and the primary products after are ytterbium
isotopes.
Standard atomic mass: 168.93421(2) u
Thulium
Thulium is a chemical element that has the symbol Tm and atomic number 69. Thulium is the second least abundant of the lanthanides . It is an easily workable metal with a bright silvery-gray luster...
(Tm) 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...
, 169Tm (100% 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...
). 34 radioisotopes have been characterized, with the most stable being 171Tm 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 1.92 years, 170Tm with a half-life of 128.6 days, 168Tm with a half-life of 93.1 days, and 167Tm with a half-life of 9.25 days. All of the remaining radioactive isotopes have half-lives that are less than 64 hours, and the majority of these have half-lives that are less than 2 minutes. This element also has 26 meta states, with the most stable being 164mTm (t½ 5.1 minutes), 160mTm (t½ 74.5 seconds) and 155mTm (t½ 45 seconds).
The isotopes of thulium range in atomic weight
Atomic weight
Atomic weight is a dimensionless physical quantity, the ratio of the average mass of atoms of an element to 1/12 of the mass of an atom of carbon-12...
from 144.97007 u
Atomic mass unit
The unified atomic mass unit or dalton is a unit that is used for indicating mass on an atomic or molecular scale. It is defined as one twelfth of the rest mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and has a value of...
(145Tm) to 178.95534 u (179Tm). The primary decay mode before the most abundant stable isotope, 169Tm, 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 after is beta emission. 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 169Tm are erbium
Erbium
Erbium is a chemical element in the lanthanide series, with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements on Earth...
isotopes, and the primary products after are ytterbium
Ytterbium
Ytterbium is a chemical element with the symbol Yb and atomic number 70. A soft silvery metallic element, ytterbium is a rare earth element of the lanthanide series and is found in the minerals gadolinite, monazite, and xenotime. The element is sometimes associated with yttrium or other related...
isotopes.
Standard atomic mass: 168.93421(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 | |||||||||
| 145Tm | 69 | 76 | 144.97007(43)# | 3.1(3) µs | (11/2-) | ||||
| 146Tm | 69 | 77 | 145.96643(43)# | 240(30) ms | 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... |
145Er | (6-) | ||
| 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... (rare) |
146Er | ||||||||
| 146mTm | 71(6) keV | 72(23) ms | 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... |
145Er | (10+) | ||||
| β+ (rare) | 146Er | ||||||||
| 147Tm | 69 | 78 | 146.96096(32)# | 0.58(3) s | β+ (85%) | 147Er | 11/2- | ||
| p (15%) | 146Er | ||||||||
| 147mTm | 60(5) keV | 360(40) µs | 3/2+ | ||||||
| 148Tm | 69 | 79 | 147.95784(43)# | 0.7(2) s | β+ | 148Er | (10+) | ||
| 148mTm | 0.7 s | ||||||||
| 149Tm | 69 | 80 | 148.95272(32)# | 0.9(2) s | β+ (99.74%) | 149Er | (11/2-) | ||
| β+, p (.26%) | 148Ho | ||||||||
| 150Tm | 69 | 81 | 149.94996(21)# | 3# s | β+ | 150Er | (1+) | ||
| 150m1Tm | 140(140)# keV | 2.20(6) s | β+ (98.8%) | 150Er | (6-) | ||||
| β+, p (1.2%) | 149Ho | ||||||||
| 150m2Tm | 810(140)# keV | 5.2(3) ms | (10+) | ||||||
| 151Tm | 69 | 82 | 150.945483(22) | 4.17(10) s | β+ | 151Er | (11/2-) | ||
| 151m1Tm | 92(7) keV | 6.6(14) s | β+ | 151Er | (1/2+) | ||||
| 151m2Tm | 2655.67(22) keV | 451(24) ns | (27/2-) | ||||||
| 152Tm | 69 | 83 | 151.94442(8) | 8.0(10) s | β+ | 152Er | (2#)- | ||
| 152m1Tm | 100(80)# keV | 5.2(6) s | β+ | 152Er | (9)+ | ||||
| 152m2Tm | 2555.05(19)+X keV | 294(12) ns | (17+) | ||||||
| 153Tm | 69 | 84 | 152.942012(20) | 1.48(1) s | 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... (91%) |
149Ho | (11/2-) | ||
| β+ (9%) | 153Er | ||||||||
| 153mTm | 43.2(2) keV | 2.5(2) s | α (92%) | 149Ho | (1/2+) | ||||
| β+ (8%) | 153Er | ||||||||
| 154Tm | 69 | 85 | 153.941568(15) | 8.1(3) s | β+ (56%) | 154Er | (2-) | ||
| α (44%) | 150Ho | ||||||||
| 154mTm | 70(50) keV | 3.30(7) s | α (90%) | 150Ho | (9+) | ||||
| β+ (10%) | 154Er | ||||||||
| 155Tm | 69 | 86 | 154.939199(14) | 21.6(2) s | β+ (98.1%) | 155Er | (11/2-) | ||
| α (1.9%) | 151Ho | ||||||||
| 155mTm | 41(6) keV | 45(3) s | β+ (92%) | 155Er | (1/2+) | ||||
| α (8%) | 151Ho | ||||||||
| 156Tm | 69 | 87 | 155.938980(17) | 83.8(18) s | β+ (99.93%) | 156Er | 2- | ||
| α (.064%) | 152Er | ||||||||
| 156mTm | 203.6(5) keV | ~400 ns | (11-) | ||||||
| 157Tm | 69 | 88 | 156.93697(3) | 3.63(9) min | β+ | 157Er | 1/2+ | ||
| 158Tm | 69 | 89 | 157.936980(27) | 3.98(6) min | β+ | 158Er | 2- | ||
| 158mTm | 50(100)# keV | ~20 ns | (5+) | ||||||
| 159Tm | 69 | 90 | 158.93498(3) | 9.13(16) min | β+ | 159Er | 5/2+ | ||
| 160Tm | 69 | 91 | 159.93526(4) | 9.4(3) min | β+ | 160Er | 1- | ||
| 160m1Tm | 70(20) keV | 74.5(15) s | 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.... (85%) |
160Tm | 5(+#) | ||||
| β+ (15%) | 160Er | ||||||||
| 160m2Tm | 98.2+X keV | ~200 ns | (8) | ||||||
| 161Tm | 69 | 92 | 160.93355(3) | 30.2(8) min | β+ | 161Er | 7/2+ | ||
| 161m1Tm | 7.4(2) keV | 5# min | 1/2+ | ||||||
| 161m2Tm | 78.20(3) keV | 110(3) ns | 7/2- | ||||||
| 162Tm | 69 | 93 | 161.933995(28) | 21.70(19) min | β+ | 162Er | 1- | ||
| 162mTm | 130(40) keV | 24.3(17) s | IT (82%) | 162Tm | 5+ | ||||
| β+ (18%) | 162Er | ||||||||
| 163Tm | 69 | 94 | 162.932651(6) | 1.810(5) h | β+ | 163Er | 1/2+ | ||
| 164Tm | 69 | 95 | 163.93356(3) | 2.0(1) min | β+ | 164Er | 1+ | ||
| 164mTm | 10(6) keV | 5.1(1) min | IT (80%) | 164Tm | 6- | ||||
| β+ (20%) | 164Er | ||||||||
| 165Tm | 69 | 96 | 164.932435(4) | 30.06(3) h | β+ | 165Er | 1/2+ | ||
| 166Tm | 69 | 97 | 165.933554(13) | 7.70(3) h | β+ | 166Er | 2+ | ||
| 166mTm | 122(8) keV | 340(25) ms | IT | 166Tm | 6- | ||||
| 167Tm | 69 | 98 | 166.9328516(29) | 9.25(2) 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... |
167Er | 1/2+ | ||
| 167m1Tm | 179.480(19) keV | 1.16(6) µs | (7/2)+ | ||||||
| 167m2Tm | 292.820(20) keV | 0.9(1) µs | 7/2- | ||||||
| 168Tm | 69 | 99 | 167.934173(3) | 93.1(2) d | β+ (99.99%) | 168Er | 3+ | ||
| β- (.01%) | 168Yb | ||||||||
| 169Tm | 69 | 100 | 168.9342133(27) | Observationally StableBelieved to undergo α decay to 165Ho | 1/2+ | 1.0000 | |||
| 170Tm | 69 | 101 | 169.9358014(27) | 128.6(3) d | β- (99.86%) | 170Yb | 1- | ||
| EC (.14%) | 170Er | ||||||||
| 170mTm | 183.197(4) keV | 4.12(13) µs | (3)+ | ||||||
| 171Tm | 69 | 102 | 170.9364294(28) | 1.92(1) a | β- | 171Yb | 1/2+ | ||
| 171mTm | 424.9560(15) keV | 2.60(2) µs | 7/2- | ||||||
| 172Tm | 69 | 103 | 171.938400(6) | 63.6(2) h | β- | 172Yb | 2- | ||
| 173Tm | 69 | 104 | 172.939604(5) | 8.24(8) h | β- | 173Yb | (1/2+) | ||
| 173mTm | 317.73(20) keV | 10(3) µs | (7/2-) | ||||||
| 174Tm | 69 | 105 | 173.94217(5) | 5.4(1) min | β- | 174Yb | (4)- | ||
| 175Tm | 69 | 106 | 174.94384(5) | 15.2(5) min | β- | 175Yb | (1/2+) | ||
| 176Tm | 69 | 107 | 175.94699(11) | 1.85(3) min | β- | 176Yb | (4+) | ||
| 177Tm | 69 | 108 | 176.94904(32)# | 90(6) s | β- | 177Yb | (7/2-) | ||
| 178Tm | 69 | 109 | 177.95264(43)# | 30# s | β- | 178Yb | |||
| 179Tm | 69 | 110 | 178.95534(54)# | 20# s | β- | 179Yb | 1/2+# | ||