Isotopes of actinium
Encyclopedia
Actinium
(Ac) has no stable isotopes, thus a standard atomic mass cannot be given. There are 31 known isotopes, from 206Ac to 236Ac, and 2 isomers
. Two isotopes are found in nature, 227Ac and 228Ac, as intermediate decay products of, respectively, 235U
and 238U
. 228Ac is extremely rare, and almost all natural actinium is 227Ac.
The most stable isotopes are 227Ac with a half-life of 21.772 years, 225Ac with a half-life of 10.0 days, and 226Ac with a half-life of 29.37 hours. All other isotopes have half-lives under 10 hours, and most under a minute. The shortest-lived known isotope is 217Ac with a half-life of 69 ns
. Actinium also has two meta states.
Purified 227Ac comes into equilibrium with its decay products (227Th and 223Fr) after 185 days.
Actinium
Actinium is a radioactive chemical element with the symbol Ac and atomic number 89, which was discovered in 1899. It was the first non-primordial radioactive element to be isolated. Polonium, radium and radon were observed before actinium, but they were not isolated until 1902...
(Ac) has no stable isotopes, thus a standard atomic mass cannot be given. There are 31 known isotopes, from 206Ac to 236Ac, and 2 isomers
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...
. Two isotopes are found in nature, 227Ac and 228Ac, as intermediate decay products of, respectively, 235U
Uranium-235
- References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...
and 238U
Uranium-238
Uranium-238 is the most common isotope of uranium found in nature. It is not fissile, but is a fertile material: it can capture a slow neutron and after two beta decays become fissile plutonium-239...
. 228Ac is extremely rare, and almost all natural actinium is 227Ac.
The most stable isotopes are 227Ac with a half-life of 21.772 years, 225Ac with a half-life of 10.0 days, and 226Ac with a half-life of 29.37 hours. All other isotopes have half-lives under 10 hours, and most under a minute. The shortest-lived known isotope is 217Ac with a half-life of 69 ns
Nanosecond
A nanosecond is one billionth of a second . One nanosecond is to one second as one second is to 31.7 years.The word nanosecond is formed by the prefix nano and the unit second. Its symbol is ns....
. Actinium also has two meta states.
Purified 227Ac comes into equilibrium with its decay products (227Th and 223Fr) after 185 days.
Table
| nuclide symbol |
historic name |
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: CD: Cluster decay Cluster decay Cluster decay is a type of nuclear decay in which a parent atomic nucleus with A nucleons and Z protons emits a cluster of Ne neutrons and Ze protons heavier than an alpha particle but lighter than a typical binary fission fragment Cluster decay (also named heavy particle radioactivity or heavy... 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 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 | ||||||||||
| 206Ac | 89 | 117 | 206.01450(8) | 25(7) ms | (3+) | |||||
| 206m1Ac | 80(50) keV | 15(6) ms | ||||||||
| 206m2Ac | 290(110)# keV | 41(16) ms | (10-) | |||||||
| 207Ac | 89 | 118 | 207.01195(6) | 31(8) ms [27(+11-6) ms] |
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... |
203Fr | 9/2-# | |||
| 208Ac | 89 | 119 | 208.01155(6) | 97(16) ms [95(+24-16) ms] |
α (99%) | 204Fr | (3+) | |||
| β+ (1%) | 208Ra | |||||||||
| 208mAc | 506(26) keV | 28(7) ms [25(+9-5) ms] |
α (89%) | 204Fr | (10-) | |||||
| 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.... (10%) |
208Ac | |||||||||
| β+ (1%) | 208Ra | |||||||||
| 209Ac | 89 | 120 | 209.00949(5) | 92(11) ms | α (99%) | 205Fr | (9/2-) | |||
| β+ (1%) | 209Ra | |||||||||
| 210Ac | 89 | 121 | 210.00944(6) | 350(40) ms | α (96%) | 206Fr | 7+# | |||
| β+ (4%) | 210Ra | |||||||||
| 211Ac | 89 | 122 | 211.00773(8) | 213(25) ms | α (99.8%) | 207Fr | 9/2-# | |||
| β+ (.2%) | 211Ra | |||||||||
| 212Ac | 89 | 123 | 212.00781(7) | 920(50) ms | α (97%) | 208Fr | 6+# | |||
| β+ (3%) | 212Ra | |||||||||
| 213Ac | 89 | 124 | 213.00661(6) | 731(17) ms | α | 209Fr | (9/2-)# | |||
| β+ (rare) | 213Ra | |||||||||
| 214Ac | 89 | 125 | 214.006902(24) | 8.2(2) s | α (89%) | 210Fr | (5+)# | |||
| β+ (11%) | 214Ra | |||||||||
| 215Ac | 89 | 126 | 215.006454(23) | 0.17(1) s | α (99.91%) | 211Fr | 9/2- | |||
| β+ (.09%) | 215Ra | |||||||||
| 216Ac | 89 | 127 | 216.008720(29) | 0.440(16) ms | α | 212Fr | (1-) | |||
| β+ (7×10−5%) | 216Ra | |||||||||
| 216mAc | 44(7) keV | 443(7) µs | (9-) | |||||||
| 217Ac | 89 | 128 | 217.009347(14) | 69(4) ns | α (98%) | 213Fr | 9/2- | |||
| β+ (2%) | 217Ra | |||||||||
| 217mAc | 2012(20) keV | 740(40) ns | (29/2)+ | |||||||
| 218Ac | 89 | 129 | 218.01164(5) | 1.08(9) µs | α | 214Fr | (1-)# | |||
| 218mAc | 584(50)# keV | 103(11) ns | (11+) | |||||||
| 219Ac | 89 | 130 | 219.01242(5) | 11.8(15) µs | α | 215Fr | 9/2- | |||
| β+ (10−6%) | 219Ra | |||||||||
| 220Ac | 89 | 131 | 220.014763(16) | 26.36(19) ms | α | 216Fr | (3-) | |||
| β+ (5×10−4%) | 220Ra | |||||||||
| 221Ac | 89 | 132 | 221.01559(5) | 52(2) ms | α | 217Fr | 9/2-# | |||
| 222Ac | 89 | 133 | 222.017844(6) | 5.0(5) s | α (99%) | 218Fr | 1- | |||
| β+ (1%) | 222Ra | |||||||||
| 222mAc | 200(150)# keV | 1.05(7) min | α (88.6%) | 218Fr | high | |||||
| IT (10%) | 222Ac | |||||||||
| β+ (1.4%) | 222Ra | |||||||||
| 223Ac | 89 | 134 | 223.019137(8) | 2.10(5) min | α (99%) | 219Fr | (5/2-) | |||
| EC Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... (1%) |
223Ra | |||||||||
| CD Cluster decay Cluster decay is a type of nuclear decay in which a parent atomic nucleus with A nucleons and Z protons emits a cluster of Ne neutrons and Ze protons heavier than an alpha particle but lighter than a typical binary fission fragment Cluster decay (also named heavy particle radioactivity or heavy... (3.2×10−9%) |
209Bi 14C Carbon-14 Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon with a nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues , to date archaeological, geological, and hydrogeological... |
|||||||||
| 224Ac | 89 | 135 | 224.021723(4) | 2.78(17) h | β+ (90.9%) | 224Ra | 0- | |||
| α (9.1%) | 220Fr | |||||||||
| β- (1.6%) | 224Th | |||||||||
| 225AcHas medical uses Nuclear medicine In nuclear medicine procedures, elemental radionuclides are combined with other elements to form chemical compounds, or else combined with existing pharmaceutical compounds, to form radiopharmaceuticals. These radiopharmaceuticals, once administered to the patient, can localize to specific organs... |
89 | 136 | 225.023230(5) | 10.0(1) d | α | 221Fr | (3/2-) | |||
| CD (6×10−10%) | 211Bi 14C |
|||||||||
| 226Ac | 89 | 137 | 226.026098(4) | 29.37(12) h | β- (83%) | 226Th | (1)(-#) | |||
| EC (17%) | 226Ra | |||||||||
| α (.006%) | 222Fr | |||||||||
| 227Ac | ActiniumSource of element's name | 89 | 138 | 227.0277521(26) | 21.772(3) a | β- (98.61%) | 227Th | 3/2- | TraceIntermediate 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... of 235U Uranium-235 - References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the... |
|
| α (1.38%) | 223Fr | |||||||||
| 228Ac | Mesothorium 2 | 89 | 139 | 228.0310211(27) | 6.15(2) h | β- | 228Th | 3+ | TraceIntermediate decay product of 232Th | |
| α (5.5×10−6%) | 224Fr | |||||||||
| 229Ac | 89 | 140 | 229.03302(4) | 62.7(5) min | β- | 229Th | (3/2+) | |||
| 230Ac | 89 | 141 | 230.03629(32) | 122(3) s | β- | 230Th | (1+) | |||
| 231Ac | 89 | 142 | 231.03856(11) | 7.5(1) min | β- | 231Th | (1/2+) | |||
| 232Ac | 89 | 143 | 232.04203(11) | 119(5) s | β- | 232Th | (1+) | |||
| 233Ac | 89 | 144 | 233.04455(32)# | 145(10) s | β- | 233Th | (1/2+) | |||
| 234Ac | 89 | 145 | 234.04842(43)# | 44(7) s | β- | 234Th | ||||
| 235Ac | 89 | 146 | 235.05123(38)# | 40# s | β- | 235Th | 1/2+# | |||
| 236Ac | 89 | 147 | 236.05530(54)# | 2# min | β- | 236Th | ||||