Isotopes of astatine
Encyclopedia
Astatine
(At) has 37 known isotope
s, all of which are radioactive; the range of their mass numbers is from 191 to 229. There exist also 23 metastable excited state
s. The longest-lived isotope is 210At, which has a half-life
of 8.1 hours; the longest-lived isotope existing in naturally occurring decay chain
s is 219At with a half-life of 56 seconds.
Astatine
Astatine is a radioactive chemical element with the symbol At and atomic number 85. It occurs on the Earth only as the result of decay of heavier elements, and decays away rapidly, so much less is known about this element than its upper neighbors in the periodic table...
(At) has 37 known 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, all of which are radioactive; the range of their mass numbers is from 191 to 229. There exist also 23 metastable excited state
Excited state
Excitation is an elevation in energy level above an arbitrary baseline energy state. In physics there is a specific technical definition for energy level which is often associated with an atom being excited to an excited state....
s. The longest-lived isotope is 210At, which has 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 8.1 hours; the longest-lived isotope existing in naturally occurring decay chain
Decay chain
In nuclear science, the decay chain refers to the radioactive decay of different discrete radioactive decay products as a chained series of transformations...
s is 219At with a half-life of 56 seconds.
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) |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|
| excitation energy | |||||||||
| 191At | 85 | 106 | 1.7(+11-5) ms | (1/2+) | |||||
| 191mAt | 2.1(+4-3) ms | (7/2-) | |||||||
| 193At | 85 | 108 | 192.99984(6) | 28(+5-4) 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... |
189Bi | (1/2+) | ||
| 193m1At | 50 keV | 21(5) ms | (7/2-) | ||||||
| 193m2At | 39 keV | 27(+4-5) ms | (13/2+) | ||||||
| 194At | 85 | 109 | 193.99873(20) | ~40 ms | α | 190Bi | 3+# | ||
| 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) |
194Po | ||||||||
| 194mAt | 480(190) keV | ~250 ms | α | 190Bi | 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.... (rare) |
194At | ||||||||
| 195At | 85 | 110 | 194.996268(10) | 328(20) ms | α (75%) | 191Bi | (1/2+) | ||
| β+ (25%) | 195Po | ||||||||
| 195mAt | 34(7) keV | 147(5) ms | 9/2-# | ||||||
| 196At | 85 | 111 | 195.99579(6) | 253(9) ms | α (96%) | 192Bi | 3+# | ||
| β+ (4%) | 196Po | ||||||||
| 196m1At | -30(80) keV | 20# ms | 10-# | ||||||
| 196m2At | 157.9(1) keV | 11 µs | 5+# | ||||||
| 197At | 85 | 112 | 196.99319(5) | 0.390(16) s | α (96%) | 193Bi | (9/2-) | ||
| β+ (4%) | 197Po | ||||||||
| 197mAt | 52(10) keV | 2.0(2) s | (1/2+) | ||||||
| 198At | 85 | 113 | 197.99284(5) | 4.2(3) s | α (94%) | 194Bi | (3+) | ||
| β+ (6%) | 198Po | ||||||||
| 198mAt | 330(90)# keV | 1.0(2) s | (10-) | ||||||
| 199At | 85 | 114 | 198.99053(5) | 6.92(13) s | α (89%) | 195Bi | (9/2-) | ||
| β+ (11%) | 199Po | ||||||||
| 200At | 85 | 115 | 199.990351(26) | 43.2(9) s | α (57%) | 196Bi | (3+) | ||
| β+ (43%) | 200Po | ||||||||
| 200m1At | 112.7(30) keV | 47(1) s | α (43%) | 196Bi | (7+) | ||||
| IT | 200At | ||||||||
| β+ | 200Po | ||||||||
| 200m2At | 344(3) keV | 3.5(2) s | (10-) | ||||||
| 201At | 85 | 116 | 200.988417(9) | 85(3) s | α (71%) | 197Bi | (9/2-) | ||
| β+ (29%) | 201Po | ||||||||
| 202At | 85 | 117 | 201.98863(3) | 184(1) s | β+ (88%) | 202Po | (2,3)+ | ||
| α (12%) | 198Bi | ||||||||
| 202m1At | 190(40) keV | 182(2) s | (7+) | ||||||
| 202m2At | 580(40) keV | 460(50) ms | (10-) | ||||||
| 203At | 85 | 118 | 202.986942(13) | 7.37(13) min | β+ (69%) | 203Po | 9/2- | ||
| α (31%) | 199Bi | ||||||||
| 204At | 85 | 119 | 203.987251(26) | 9.2(2) min | β+ (96.2%) | 204Po | 7+ | ||
| α (3.8%) | 200Bi | ||||||||
| 204mAt | 587.30(20) keV | 108(10) ms | IT | 204At | (10-) | ||||
| 205At | 85 | 120 | 204.986074(16) | 26.2(5) min | β+ (90%) | 205Po | 9/2- | ||
| α (10%) | 201Bi | ||||||||
| 205mAt | 2339.65(23) keV | 7.76(14) µs | 29/2+ | ||||||
| 206At | 85 | 121 | 205.986667(22) | 30.6(13) min | β+ (99.11%) | 206Po | (5)+ | ||
| α (.89%) | 202Bi | ||||||||
| 206mAt | 807(3) keV | 410(80) ns | (10)- | ||||||
| 207At | 85 | 122 | 206.985784(23) | 1.80(4) h | β+ (91.4%) | 207Po | 9/2- | ||
| α (8.6%) | 203Bi | ||||||||
| 208At | 85 | 123 | 207.986590(28) | 1.63(3) h | β+ (99.45%) | 208Po | 6+ | ||
| α (.55%) | 204Bi | ||||||||
| 209At | 85 | 124 | 208.986173(8) | 5.41(5) h | β+ (95.9%) | 209Po | 9/2- | ||
| α (4.1%) | 205Bi | ||||||||
| 210At | 85 | 125 | 209.987148(8) | 8.1(4) h | β+ (99.82%) | 210Po | (5)+ | ||
| α (.175%) | 206Bi | ||||||||
| 210m1At | 2549.6(2) keV | 482(6) µs | (15)- | ||||||
| 210m2At | 4027.7(2) keV | 5.66(7) µs | (19)+ | ||||||
| 211At | 85 | 126 | 210.9874963(30) | 7.214(7) h | EC Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... (58.2%) |
211Po | 9/2- | ||
| α (41.8%) | 207Bi | ||||||||
| 212At | 85 | 127 | 211.990745(8) | 0.314(2) s | α (99.97%) | 208Bi | (1-) | ||
| β+ (.03%) | 212Po | ||||||||
| β- (2×10−6%) | 212Rn | ||||||||
| 212m1At | 223(7) keV | 0.119(3) s | α (99%) | 208Bi | (9-) | ||||
| IT (1%) | 212At | ||||||||
| 212m2At | 4771.6(11) keV | 152(5) µs | (25-) | ||||||
| 213At | 85 | 128 | 212.992937(5) | 125(6) ns | α | 209Bi | 9/2- | ||
| 214At | 85 | 129 | 213.996372(5) | 558(10) ns | α | 210Bi | 1- | ||
| 214m1At | 59(9) keV | 265(30) ns | |||||||
| 214m2At | 231(6) keV | 760(15) ns | 9- | ||||||
| 215At | 85 | 130 | 214.998653(7) | 0.10(2) ms | α | 211Bi | 9/2- | 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... |
|
| 216At | 85 | 131 | 216.002423(4) | 0.30(3) ms | α (99.99%) | 212Bi | 1- | ||
| β- (.006%) | 216Rn | ||||||||
| EC (3×10−7%) | 216Po | ||||||||
| 216mAt | 413(5) keV | 100# µs | (9-) | ||||||
| 217At | 85 | 132 | 217.004719(5) | 32.3(4) ms | α (99.98%) | 213Bi | 9/2- | ||
| β- (.012%) | 217Rn | ||||||||
| 218At | 85 | 133 | 218.008694(12) | 1.5(3) s | α (99.9%) | 214Bi | 1-# | TraceIntermediate decay product of 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... |
|
| β- (.1%) | 218Rn | ||||||||
| 219At | 85 | 134 | 219.011162(4) | 56(3) s | α (97%) | 215Bi | 5/2-# | Trace | |
| β- (3%) | 219Rn | ||||||||
| 220At | 85 | 135 | 220.01541(6) | 3.71(4) min | β- (92%) | 220Rn | 3(-#) | ||
| α (8%) | 216Bi | ||||||||
| 221At | 85 | 136 | 221.01805(21)# | 2.3(2) min | β- | 221Rn | 3/2-# | ||
| 222At | 85 | 137 | 222.02233(32)# | 54(10) s | β- | 222Rn | |||
| 223At | 85 | 138 | 223.02519(43)# | 50(7) s | 3/2-# | ||||