Isotopes of cobalt
Encyclopedia
Naturally occurring cobalt
(Co) is composed of 1 stable isotope
, 59Co. 28 radioisotopes have been characterized with the most stable being 60Co with a half-life
of 5.2714 years, 57Co with a half-life of 271.79 days, 56Co with a half-life of 77.27 days, and 58Co with a half-life of 70.86 days. All of the remaining radioactive isotopes have half-lives that are less than 18 hours and the majority of these have half-lives that are less than 1 second. This element also has 11 meta states, all of which have half-lives less than 15 minutes.
The isotopes of cobalt range in atomic weight
from 47Co to 75Co. The primary decay mode for isotopes with atomic mass unit values less than that of the most abundant stable isotope, 59Co, is electron capture
and the primary mode of decay for those of greater than 59 atomic mass units is beta decay
. The primary decay product
s before 59Co are iron
isotopes and the primary products after are nickel
isotopes.
Standard atomic mass: 58.933195(5) u
. It produces two gamma ray
s with energies of 1.17 MeV
and 1.33 MeV
. The 60Co source is about 2 cm in diameter
and as a result produces a geometric penumbra, making the edge of the radiation
field fuzzy. The metal has the unfortunate habit of producing a fine dust, causing problems with radiation
protection. The 60Co source is useful for about 5 years but even after this point is still very radioactive, and so cobalt machines have fallen from favor in the Western world where linacs are common.
Cobalt-57 (Co-57 or 57Co) is a radioactive metal that is used in medical tests; it is used as a radiolabel for vitamin B12 uptake. It is useful for the Schilling test
.
source because it can be produced—in predictable quantity, and high activity—by simply exposing natural cobalt to neutron
s in a reactor for a given time. It is used for
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....
(Co) 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...
, 59Co. 28 radioisotopes have been characterized with the most stable being 60Co 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 5.2714 years, 57Co with a half-life of 271.79 days, 56Co with a half-life of 77.27 days, and 58Co with a half-life of 70.86 days. All of the remaining radioactive isotopes have half-lives that are less than 18 hours and the majority of these have half-lives that are less than 1 second. This element also has 11 meta states, all of which have half-lives less than 15 minutes.
The isotopes of cobalt 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 47Co to 75Co. The primary decay mode for isotopes with atomic mass unit values less than that of the most abundant stable isotope, 59Co, 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 of decay for those of greater than 59 atomic mass units is beta decay
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...
. 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 59Co are iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
isotopes and the primary products after are nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
isotopes.
Standard atomic mass: 58.933195(5) u
Use of cobalt radioisotopes in medicine
Cobalt-60 (Co-60 or 60Co) is a radioactive metal that is used in radiotherapyRadiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
. It produces two 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...
s with energies of 1.17 MeV
MEV
MeV and meV are multiples and submultiples of the electron volt unit referring to 1,000,000 eV and 0.001 eV, respectively.Mev or MEV may refer to:In entertainment:* Musica Elettronica Viva, an Italian musical group...
and 1.33 MeV
MEV
MeV and meV are multiples and submultiples of the electron volt unit referring to 1,000,000 eV and 0.001 eV, respectively.Mev or MEV may refer to:In entertainment:* Musica Elettronica Viva, an Italian musical group...
. The 60Co source is about 2 cm in diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
and as a result produces a geometric penumbra, making the edge of the radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
field fuzzy. The metal has the unfortunate habit of producing a fine dust, causing problems with radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
protection. The 60Co source is useful for about 5 years but even after this point is still very radioactive, and so cobalt machines have fallen from favor in the Western world where linacs are common.
Cobalt-57 (Co-57 or 57Co) is a radioactive metal that is used in medical tests; it is used as a radiolabel for vitamin B12 uptake. It is useful for the Schilling test
Schilling test
The Schilling test is a medical investigation used for patients with vitamin B deficiency. The purpose of the test is to determine whether the patient has pernicious anemia.It is named for Robert F. Schilling.-Process:The Schilling test has multiple stages...
.
Industrial uses for radioactive isotopes
Cobalt-60 (Co-60 or 60Co) is useful as a gamma rayGamma 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...
source because it can be produced—in predictable quantity, and high activity—by simply exposing natural cobalt to neutron
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...
s in a reactor for a given time. It is used for
- sterilization of medical supplies, and medical waste;
- radiationRadiationIn physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
treatment of foods for sterilizationFood irradiationFood irradiation is the process of exposing food to ionizing radiation to destroy microorganisms, bacteria, viruses, or insects that might be present in the food. Further applications include sprout inhibition, delay of ripening, increase of juice yield, and improvement of re-hydration...
(cold pasteurizationPasteurizationPasteurization is a process of heating a food, usually liquid, to a specific temperature for a definite length of time, and then cooling it immediately. This process slows microbial growth in food...
); - industrial radiographyRadiographyRadiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....
(e.g., weld integrity radiographs); - density measurements (e.g., concrete density measurements); and
- tank fill height switches.
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 | |||||||||
| 47Co | 27 | 20 | 47.01149(54)# | 7/2-# | |||||
| 48Co | 27 | 21 | 48.00176(43)# | 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... |
47Fe | 6+# | |||
| 49Co | 27 | 22 | 48.98972(28)# | <35 ns | p (>99.9%) | 48Fe | 7/2-# | ||
| 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%) |
49Fe | ||||||||
| 50Co | 27 | 23 | 49.98154(18)# | 44(4) ms | β+, p (54%) | 49Mn | (6+) | ||
| β+ (46%) | 50Fe | ||||||||
| 51Co | 27 | 24 | 50.97072(16)# | 60# ms [>200 ns] | β+ | 51Fe | 7/2-# | ||
| 52Co | 27 | 25 | 51.96359(7)# | 115(23) ms | β+ | 52Fe | (6+) | ||
| 52mCo | 380(100)# keV | 104(11)# ms | β+ | 52Fe | 2+# | ||||
| 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.... |
52Co | ||||||||
| 53Co | 27 | 26 | 52.954219(19) | 242(8) ms | β+ | 53Fe | 7/2-# | ||
| 53mCo | 3197(29) keV | 247(12) ms | β+ (98.5%) | 53Fe | (19/2-) | ||||
| p (1.5%) | 52Fe | ||||||||
| 54Co | 27 | 27 | 53.9484596(8) | 193.28(7) ms | β+ | 54Fe | 0+ | ||
| 54mCo | 197.4(5) keV | 1.48(2) min | β+ | 54Fe | (7)+ | ||||
| 55Co | 27 | 28 | 54.9419990(8) | 17.53(3) h | β+ | 55Fe | 7/2- | ||
| 56Co | 27 | 29 | 55.9398393(23) | 77.233(27) d | β+ | 56Fe | 4+ | ||
| 57Co | 27 | 30 | 56.9362914(8) | 271.74(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... |
57Fe | 7/2- | ||
| 58Co | 27 | 31 | 57.9357528(13) | 70.86(6) d | β+ | 58Fe | 2+ | ||
| 58m1Co | 24.95(6) keV | 9.04(11) h | IT | 58Co | 5+ | ||||
| 58m2Co | 53.15(7) keV | 10.4(3) µs | 4+ | ||||||
| 59Co | 27 | 32 | 58.9331950(7) | Stable | 7/2- | 1.0000 | |||
| 60Co Cobalt-60 Cobalt-60, , is a synthetic radioactive isotope of cobalt. Due to its half-life of 5.27 years, is not found in nature. It is produced artificially by neutron activation of . decays by beta decay to the stable isotope nickel-60... |
27 | 33 | 59.9338171(7) | 5.2713(8) a | β- | 60Ni | 5+ | ||
| 60mCo | 58.59(1) keV | 10.467(6) min | IT (99.76%) | 60Co | 2+ | ||||
| β- (.24%) | 60Ni | ||||||||
| 61Co | 27 | 34 | 60.9324758(10) | 1.650(5) h | β- | 61Ni | 7/2- | ||
| 62Co | 27 | 35 | 61.934051(21) | 1.50(4) min | β- | 62Ni | 2+ | ||
| 62mCo | 22(5) keV | 13.91(5) min | β- (99%) | 62Ni | 5+ | ||||
| IT (1%) | 62Co | ||||||||
| 63Co | 27 | 36 | 62.933612(21) | 26.9(4) s | β- | 63Ni | 7/2- | ||
| 64Co | 27 | 37 | 63.935810(21) | 0.30(3) s | β- | 64Ni | 1+ | ||
| 65Co | 27 | 38 | 64.936478(14) | 1.20(6) s | β- | 65Ni | (7/2)- | ||
| 66Co | 27 | 39 | 65.93976(27) | 0.18(1) s | β- | 66Ni | (3+) | ||
| 66m1Co | 175(3) keV | 1.21(1) µs | (5+) | ||||||
| 66m2Co | 642(5) keV | >100 µs | (8-) | ||||||
| 67Co | 27 | 40 | 66.94089(34) | 0.425(20) s | β- | 67Ni | (7/2-)# | ||
| 68Co | 27 | 41 | 67.94487(34) | 0.199(21) s | β- | 68Ni | (7-) | ||
| 68mCo | 150(150)# keV | 1.6(3) s | (3+) | ||||||
| 69Co | 27 | 42 | 68.94632(36) | 227(13) ms | β- (>99.9%) | 69Ni | 7/2-# | ||
| β-, n Neutron emission Neutron emission is a type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus. Two examples of isotopes which emit neutrons are helium-5 and beryllium-13... (<.1%) |
68Ni | ||||||||
| 70Co | 27 | 43 | 69.9510(9) | 119(6) ms | β- (>99.9%) | 70Ni | (6-) | ||
| β-, n (<.1%) | 69Ni | ||||||||
| 70mCo | 200(200)# keV | 500(180) ms | (3+) | ||||||
| 71Co | 27 | 44 | 70.9529(9) | 97(2) ms | β- (>99.9%) | 71Ni | 7/2-# | ||
| β-, n (<.1%) | 70Ni | ||||||||
| 72Co | 27 | 45 | 71.95781(64)# | 62(3) ms | β- (>99.9%) | 72Ni | (6-,7-) | ||
| β-, n (<.1%) | 71Ni | ||||||||
| 73Co | 27 | 46 | 72.96024(75)# | 41(4) ms | 7/2-# | ||||
| 74Co | 27 | 47 | 73.96538(86)# | 50# ms [>300 ns] | 0+ | ||||
| 75Co | 27 | 48 | 74.96833(86)# | 40# ms [>300 ns] | 7/2-# | ||||