Isotopes of polonium
Encyclopedia
Polonium
(Po) has 42 isotopes, all of which are radioactive, with between 186 and 227 nucleons. 210Po with a half-life of 138.376 days has the longest half-life of naturally occurring polonium. 209Po with a half-life of 103 years has the longest half-life of all isotopes of polonium. 209Po and 208Po (half-life 2.9 years) can be made through the alpha, proton, or deuteron bombardment of lead
or bismuth
in a cyclotron
.
that has a half-life of 138.376 days; it decays directly to its daughter isotope
206Pb. A milligram of 210Po emits as many alpha particles per second as 4.215 grams of 226Ra. A few curie
s (1 curie equals 37 gigabecquerels
) of 210Po emit a blue glow which is caused by excitation
of surrounding air. A single gram of 210Po generates 140 watts of power. Because it emits many alpha particles, which are stopped within a very short distance in dense media and release their energy, 210Po has been used as a lightweight heat source to power thermoelectric cells
in artificial satellites; for instance, 210Po heat source was also used in each of the Lunokhod rovers deployed on the surface of the Moon
, to keep their internal components warm during the lunar nights. Some anti-static brushes contain up to 500 microcuries of 210Po as a source of charged particles for neutralizing static electricity in materials like photographic film. 210Po was used to kill Russian dissident and ex-FSB officer Alexander V. Litvinenko
in 2006.
The majority of the time 210Po decays by emission of an alpha particle
only, not by emission of an alpha particle and a gamma ray
. About one in 100,000 decays results in the emission of a gamma ray. This low gamma ray production rate makes it more difficult to find and identify this isotope. Rather than gamma ray spectroscopy, alpha spectroscopy is the best method of measuring this isotope.
210Po occurs in minute amounts in nature, where it is an intermediate isotope in the radium series (also known as the uranium series) decay chain
. It is generated via beta decay from 210Bi
.
Polonium
Polonium is a chemical element with the symbol Po and atomic number 84, discovered in 1898 by Marie Skłodowska-Curie and Pierre Curie. A rare and highly radioactive element, polonium is chemically similar to bismuth and tellurium, and it occurs in uranium ores. Polonium has been studied for...
(Po) has 42 isotopes, all of which are radioactive, with between 186 and 227 nucleons. 210Po with a half-life of 138.376 days has the longest half-life of naturally occurring polonium. 209Po with a half-life of 103 years has the longest half-life of all isotopes of polonium. 209Po and 208Po (half-life 2.9 years) can be made through the alpha, proton, or deuteron bombardment of lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
or bismuth
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...
in a cyclotron
Cyclotron
In technology, a cyclotron is a type of particle accelerator. In physics, the cyclotron frequency or gyrofrequency is the frequency of a charged particle moving perpendicularly to the direction of a uniform magnetic field, i.e. a magnetic field of constant magnitude and direction...
.
210Po
210Po is an alpha emitterAlpha 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...
that has a half-life of 138.376 days; it decays directly to its daughter isotope
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...
206Pb. A milligram of 210Po emits as many alpha particles per second as 4.215 grams of 226Ra. A few curie
Curie
The curie is a unit of radioactivity, defined asThis is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. In addition to the curie, activity can be measured using an SI derived unit,...
s (1 curie equals 37 gigabecquerels
Becquerel
The becquerel is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The Bq unit is therefore equivalent to an inverse second, s−1...
) of 210Po emit a blue glow which is caused by excitation
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....
of surrounding air. A single gram of 210Po generates 140 watts of power. Because it emits many alpha particles, which are stopped within a very short distance in dense media and release their energy, 210Po has been used as a lightweight heat source to power thermoelectric cells
Radioisotope thermoelectric generator
A radioisotope thermoelectric generator is an electrical generator that obtains its power from radioactive decay. In such a device, the heat released by the decay of a suitable radioactive material is converted into electricity by the Seebeck effect using an array of thermocouples.RTGs can be...
in artificial satellites; for instance, 210Po heat source was also used in each of the Lunokhod rovers deployed on the surface of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
, to keep their internal components warm during the lunar nights. Some anti-static brushes contain up to 500 microcuries of 210Po as a source of charged particles for neutralizing static electricity in materials like photographic film. 210Po was used to kill Russian dissident and ex-FSB officer Alexander V. Litvinenko
Alexander Litvinenko
Alexander Valterovich Litvinenko was an officer who served in the Soviet KGB and its Russian successor, the Federal Security Service ....
in 2006.
The majority of the time 210Po decays by emission of an alpha particle
Alpha particle
Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus, which is classically produced in the process of alpha decay, but may be produced also in other ways and given the same name...
only, not by emission of an alpha particle and a gamma ray
Gamma ray
Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency . Gamma rays are usually naturally produced on Earth by decay of high energy states in atomic nuclei...
. About one in 100,000 decays results in the emission of a gamma ray. This low gamma ray production rate makes it more difficult to find and identify this isotope. Rather than gamma ray spectroscopy, alpha spectroscopy is the best method of measuring this isotope.
210Po occurs in minute amounts in nature, where it is an intermediate isotope in the radium series (also known as the uranium series) 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...
. It is generated via beta decay from 210Bi
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...
.
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: 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 | ||||||||||
| 188Po | 84 | 104 | 187.999422(21) | 430(180) µs [0.40(+20-15) ms] |
0+ | |||||
| 189Po | 84 | 105 | 188.998481(24) | 5(1) ms | 3/2-# | |||||
| 190Po | 84 | 106 | 189.995101(14) | 2.46(5) 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... (99.9%) |
186Pb | 0+ | |||
| 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... (.1%) |
190Bi | |||||||||
| 191Po | 84 | 107 | 190.994574(12) | 22(1) ms | α | 187Pb | 3/2-# | |||
| β+ (rare) | 191Bi | |||||||||
| 191mPo | 130(21) keV | 93(3) ms | (13/2+) | |||||||
| 192Po | 84 | 108 | 191.991335(13) | 32.2(3) ms | α (99%) | 188Pb | 0+ | |||
| β+ (1%) | 192Bi | |||||||||
| 192mPo | 2600(500)# keV | ~1 µs | 12+# | |||||||
| 193Po | 84 | 109 | 192.99103(4) | 420(40) ms [370(+46-40) ms] |
α | 189Pb | 3/2-# | |||
| β+ (rare) | 193Bi | |||||||||
| 193mPo | 100(30)# keV | 240(10) ms [243(+11-10) ms] |
α | 189Pb | (13/2+) | |||||
| β+ (rare) | 193Bi | |||||||||
| 194Po | 84 | 110 | 193.988186(13) | 0.392(4) s | α | 190Pb | 0+ | |||
| β+ (rare) | 194Bi | |||||||||
| 194mPo | 2525(2) keV | 15(2) µs | (11-) | |||||||
| 195Po | 84 | 111 | 194.98811(4) | 4.64(9) s | α (75%) | 191Pb | 3/2-# | |||
| β+ (25%) | 195Bi | |||||||||
| 195mPo | 110(50) keV | 1.92(2) s | α (90%) | 191Pb | 13/2+# | |||||
| β+ (10%) | 195Bi | |||||||||
| 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.... (.01%) |
195Po | |||||||||
| 196Po | 84 | 112 | 195.985535(14) | 5.56(12) s | α (94%) | 192Pb | 0+ | |||
| β+ (6%) | 196Bi | |||||||||
| 196mPo | 2490.5(17) keV | 850(90) ns | (11-) | |||||||
| 197Po | 84 | 113 | 196.98566(5) | 53.6(10) s | β+ (54%) | 197Bi | (3/2-) | |||
| α (44%) | 193Pb | |||||||||
| 197mPo | 230(80)# keV | 25.8(1) s | α (84%) | 193Pb | (13/2+) | |||||
| β+ (16%) | 197Bi | |||||||||
| IT (.01%) | 197Po | |||||||||
| 198Po | 84 | 114 | 197.983389(19) | 1.77(3) min | α (57%) | 194Pb | 0+ | |||
| β+ (43%) | 198Bi | |||||||||
| 198m1Po | 2565.92(20) keV | 200(20) ns | 11- | |||||||
| 198m2Po | 2691.86(20) keV | 750(50) ns | 12+ | |||||||
| 199Po | 84 | 115 | 198.983666(25) | 5.48(16) min | β+ (92.5%) | 199Bi | (3/2-) | |||
| α (7.5%) | 195Pb | |||||||||
| 199mPo | 312.0(28) keV | 4.17(4) min | β+ (73.5%) | 199Bi | 13/2+ | |||||
| α (24%) | 195Pb | |||||||||
| IT (2.5%) | 199Po | |||||||||
| 200Po | 84 | 116 | 199.981799(15) | 11.5(1) min | β+ (88.8%) | 200Bi | 0+ | |||
| α (11.1%) | 196Pb | |||||||||
| 201Po | 84 | 117 | 200.982260(6) | 15.3(2) min | β+ (98.4%) | 201Bi | 3/2- | |||
| α (1.6%) | 197Pb | |||||||||
| 201mPo | 424.1(24) keV | 8.9(2) min | IT (56%) | 201Po | 13/2+ | |||||
| EC Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... (41%) |
201Bi | |||||||||
| α (2.9%) | 197Pb | |||||||||
| 202Po | 84 | 118 | 201.980758(16) | 44.7(5) min | β+ (98%) | 202Bi | 0+ | |||
| α (2%) | 198Pb | |||||||||
| 202mPo | 2626.7(7) keV | >200 ns | 11- | |||||||
| 203Po | 84 | 119 | 202.981420(28) | 36.7(5) min | β+ (99.89%) | 203Bi | 5/2- | |||
| α (.11%) | 199Pb | |||||||||
| 203m1Po | 641.49(17) keV | 45(2) s | IT (99.96%) | 203Po | 13/2+ | |||||
| α (.04%) | 199Pb | |||||||||
| 203m2Po | 2158.5(6) keV | >200 ns | ||||||||
| 204Po | 84 | 120 | 203.980318(12) | 3.53(2) h | β+ (99.33%) | 204Bi | 0+ | |||
| α (.66%) | 200Pb | |||||||||
| 205Po | 84 | 121 | 204.981203(21) | 1.66(2) h | β+ (99.96%) | 205Bi | 5/2- | |||
| α (.04%) | 201Pb | |||||||||
| 205m1Po | 143.166(17) keV | 310(60) ns | 1/2- | |||||||
| 205m2Po | 880.30(4) keV | 645 µs | 13/2+ | |||||||
| 205m3Po | 1461.21(21) keV | 57.4(9) ms | IT | 205Po | 19/2- | |||||
| 205m4Po | 3087.2(4) keV | 115(10) ns | 29/2- | |||||||
| 206Po | 84 | 122 | 205.980481(9) | 8.8(1) d | β+ (94.55%) | 206Bi | 0+ | |||
| α (5.45%) | 202Pb | |||||||||
| 206m1Po | 1585.85(11) keV | 222(10) ns | (8+)# | |||||||
| 206m2Po | 2262.22(14) keV | 1.05(6) µs | (9-)# | |||||||
| 207Po | 84 | 123 | 206.981593(7) | 5.80(2) h | β+ (99.97%) | 207Bi | 5/2- | |||
| α (.021%) | 203Pb | |||||||||
| 207m1Po | 68.573(14) keV | 205(10) ns | 1/2- | |||||||
| 207m2Po | 1115.073(16) keV | 49(4) µs | 13/2+ | |||||||
| 207m3Po | 1383.15(6) keV | 2.79(8) s | IT | 207Po | 19/2- | |||||
| 208Po | 84 | 124 | 207.9812457(19) | 2.898(2) a | α (99.99%) | 204Pb | 0+ | |||
| β+ (.00277%) | 208Bi | |||||||||
| 209Po | 84 | 125 | 208.9824304(20) | 102(5) a | α (99.52%) | 205Pb | 1/2- | |||
| β+ (.48%) | 209Bi | |||||||||
| 210Po | Radium F | 84 | 126 | 209.9828737(13) | 138.376(2) d | α | 206Pb | 0+ | 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 Uranium-238 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... |
|
| 210mPo | 5057.61(4) keV | 263(5) ns | 16+ | |||||||
| 211Po | Actinium C' | 84 | 127 | 210.9866532(14) | 0.516(3) s | α | 207Pb | 9/2+ | TraceIntermediate decay product of Uranium-235 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... |
|
| 211m1Po | 1462(5) keV | 25.2(6) s | α (99.98%) | 207Pb | (25/2+) | |||||
| IT (.016%) | 211Po | |||||||||
| 211m2Po | 2135.7(9) keV | 243(21) ns | (31/2-) | |||||||
| 211m3Po | 4873.3(17) keV | 2.8(7) µs | (43/2+) | |||||||
| 212Po | Thorium C' | 84 | 128 | 211.9888680(13) | 299(2) ns | α | 208Pb | 0+ | TraceIntermediate decay product of Thorium-232 | |
| 212mPo | 2911(12) keV | 45.1(6) s | α (99.93%) | 208Pb | (18+) | |||||
| IT (.07%) | 212Po | |||||||||
| 213Po | 84 | 129 | 212.992857(3) | 3.65(4) µs | α | 209Pb | 9/2+ | |||
| 214Po | Radium C' | 84 | 130 | 213.9952014(16) | 164.3(20) µs | α | 210Pb | 0+ | Trace | |
| 215Po | Actinium A | 84 | 131 | 214.9994200(27) | 1.781(4) ms | α (99.99%) | 211Pb | 9/2+ | Trace | |
| β- (2.3×10−4%) | 215At | |||||||||
| 216Po | Thorium A | 84 | 132 | 216.0019150(24) | 0.145(2) s | α | 212Pb | 0+ | Trace | |
| β-β- (rare) | 216Rn | |||||||||
| 217Po | 84 | 133 | 217.006335(7) | 1.47(5) s | α (95%) | 213Pb | 5/2+# | |||
| β- (5%) | 217At | |||||||||
| 218Po | Radium A | 84 | 134 | 218.0089730(26) | 3.10(1) min | α (99.98%) | 214Pb | 0+ | Trace | |
| β- (.02%) | 218At | |||||||||
| 219Po | 84 | 135 | 219.01374(39)# | 2# min [>300 ns] |
7/2+# | |||||
| 220Po | 84 | 136 | 220.01660(39)# | 40# s [>300 ns] |
0+ | |||||