Isotopes of cobalt

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Isotopes of cobalt  (27Co)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
56Co synth 77.236 d β+ 56Fe
57Cosynth271.811 d ε 57Fe
58Cosynth70.844 dβ+ 58Fe
59Co100% stable
60Co trace 5.2714 y β− 100% 60Ni
Standard atomic weight Ar°(Co)

Naturally occurring cobalt, Co, consists of a single stable isotope, 59Co (thus, cobalt is a mononuclidic element). Twenty-eight radioisotopes have been characterized; the most stable are 60Co with a half-life of 5.2714 years, 57Co (271.811 days), 56Co (77.236 days), and 58Co (70.844 days). All other isotopes have half-lives of less than 18 hours and most of these have half-lives of less than 1 second. This element also has 19 meta states, of which the most stable is 58m1Co with a half-life of 8.853 h.

Contents

The isotopes of cobalt range in atomic weight from 50Co to 78Co. The main decay mode for isotopes with atomic mass less than that of the stable isotope, 59Co, is electron capture and the main mode of decay for those of greater than 59 atomic mass units is beta decay. The main decay products before 59Co are iron isotopes and the main products after are nickel isotopes.

Radioisotopes can be produced by various nuclear reactions. For example, 57Co is produced by cyclotron irradiation of iron. The main reaction is the (d,n) reaction 56Fe + 2H → n + 57Co. [4]

List of isotopes


Nuclide
[n 1] 		Z N Isotopic mass (Da) [5]
[n 2] [n 3] 		Half-life [1]
[n 4] 		Decay
mode [1]
[n 5] 		Daughter
isotope
[n 6] 		Spin and
parity [1]
[n 7] [n 4] 		Isotopic
abundance
Excitation energy [n 4]
50Co272349.98112(14)38.8(2) msβ+, p (70.5%)49Mn(6+)
β+ (29.5%)50Fe
β+, 2p?48Mn
51Co272450.970647(52)68.8(19) msβ+ (96.2%)51Fe7/2−
β+, p (<3.8%)50Mn
52Co272551.9631302(57)111.7(21) msβ+52Fe6+
β+, p?51Mn
52mCo376(9) keV102(5) msβ+52Fe2+
IT?52Co
β+, p?51Mn
53Co272652.9542033(19)244.6(28) msβ+53Fe7/2−#
53mCo3174.3(9) keV250(10) msβ+? (~98.5%)53Fe(19/2−)
p (~1.5%)52Fe
54Co272753.94845908(38)193.27(6) msβ+54Fe0+
54mCo197.57(10) keV1.48(2) minβ+54Fe7+
55Co272854.94199642(43)17.53(3) hβ+55Fe7/2−
56Co272955.93983803(51)77.236(26) dβ+56Fe4+
57Co273056.93628982(55)271.811(32) d EC 57Fe7/2−
58Co273157.9357513(12)70.844(20) dEC (85.21%)58Fe2+
β+ (14.79%)58Fe
58m1Co24.95(6) keV8.853(23) hIT58Co5+
EC (0.00120%)58Fe
58m2Co53.15(7) keV10.5(3) μsIT58Co4+
59Co273258.93319352(43)Stable7/2−1.0000
60Co 273359.93381554(43)5.2714(6) yβ−60Ni5+
60mCo58.59(1) keV10.467(6) minIT (99.75%)60Co2+
β− (0.25%)60Ni
61Co273460.93247603(90)1.649(5) hβ−61Ni7/2−
62Co273561.934058(20)1.54(10) minβ−62Ni(2)+
62mCo22(5) keV13.86(9) minβ− (>99.5%)62Ni(5)+
IT (<0.5%)62Co
63Co273662.933600(20)26.9(4) sβ−63Ni7/2−
64Co273763.935810(21)300(30) msβ−64Ni1+
64mCo107(20) keV300# msβ−?64Ni5+#
IT?64Co
65Co273864.9364621(22)1.16(3) sβ−65Ni(7/2)−
66Co273965.939443(15)194(17) msβ−66Ni(1+)
β−, n?65Ni
66m1Co175.1(3) keV824(22) nsIT66Co(3+)
66m2Co642(5) keV>100 μsIT66Co(8−)
67Co274066.9406096(69)329(28) msβ−67Ni(7/2−)
β−, n?66Ni
67mCo491.55(11) keV496(33) msIT (>80%)67Co(1/2−)
β−67Ni
68Co274167.9445594(41)200(20) msβ−68Ni(7−)
β−, n?67Ni
68m1Co [n 8] 150(150)# keV1.6(3) sβ−68Ni(2−)
β−, n (>2.6%)67Ni
68m2Co195(150)# keV101(10) nsIT68Co(1)
69Co274268.945909(92)180(20) msβ−69Ni(7/2−)
β−, n?68Ni
69mCo [n 8] 170(90) keV750(250) msβ−69Ni1/2−#
70Co274369.950053(12)508(7) msβ−70Ni(1+)
β−, n?69Ni
β−, 2n?68Ni
70mCo [n 8] 200(200)# keV112(7) msβ−70Ni(7−)
IT?70Co
β−, n?69Ni
β−, 2n?68Ni
71Co274470.95237(50)80(3) msβ− (97%)71Ni(7/2−)
β−, n (3%)70Ni
72Co274571.95674(32)#51.5(3) msβ− (<96%)72Ni(6−,7−)
β−, n (>4%)71Ni
β−, 2n?70Ni
72mCo [n 8] 200(200)# keV47.8(5) msβ−72Ni(0+,1+)
73Co274672.95924(32)#42.0(8) msβ− (94%)73Ni(7/2−)
β−, n (6%)72Ni
β−, 2n?71Ni
74Co274773.96399(43)#31.3(13) msβ− (82%)74Ni7−#
β−, n (18%)73Ni
β−, 2n?72Ni
75Co274874.96719(43)#26.5(12) msβ− (>84%)75Ni7/2−#
β−, n (<16%)74Ni
β−, 2n?73Ni
76Co274975.97245(54)#23(6) msβ−76Ni(8−)
β−, n?75Ni
β−, 2n?74Ni
76m1Co [n 8] 100(100)# keV16(4) msβ−76Ni(1−)
76m2Co740(100)# keV2.99(27) μsIT76Co(3+)
77Co275076.97648(64)#15(6) msβ−77Ni7/2−#
β−, n?76Ni
β−, 2n?75Ni
β−, 3n?74Ni
78Co275177.983 55(75)#11# ms
[>410 ns]		β−?78Ni
This table header & footer:
  1. ↑ mCo – Excited nuclear isomer.
  2. ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. 1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. ↑ Modes of decay:
    EC: Electron capture
    IT: Isomeric transition
    n: Neutron emission
    p: Proton emission
  6. ↑ Bold symbol as daughter – Daughter product is stable.
  7. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  8. 1 2 3 4 5 Order of ground state and isomer is uncertain.

Stellar nucleosynthesis of cobalt-56

One of the terminal nuclear reactions in stars prior to supernova produces 56Ni. Following its production, 56Ni decays to 56Co, and then 56Co subsequently decays to 56Fe. These decay reactions power the luminosity displayed in light decay curves. Both the light decay and radioactive decay curves are expected to be exponential. Therefore, the light decay curve should give an indication of the nuclear reactions powering it. This has been confirmed by observation of bolometric light decay curves for SN 1987A. Between 600 and 800 days after SN1987A occurred, the bolometric light curve decreased at an exponential rate with half-life values from τ1/2 = 68.6 days to τ1/2 = 69.6 days. [6] The rate at which the luminosity decreased closely matched the exponential decay of 56Co with a half-life of τ1/2 = 77.233 days.

Use of cobalt radioisotopes in medicine

Cobalt-57 (57Co or Co-57) is used in medical tests; it is used as a radiolabel for vitamin B12 uptake. It is useful for the Schilling test. [7]

Cobalt-60 (60Co or Co-60) is used in radiotherapy. It produces two gamma rays 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 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.

Industrial uses for radioactive isotopes

Cobalt-60 (60Co) is useful as a gamma ray source because it can be produced in predictable quantities, and for its high radioactivity simply by exposing natural cobalt to neutrons in a reactor. [8] The uses for industrial cobalt include:

57Co is used as a source in Mössbauer spectroscopy of iron-containing samples. Electron capture by 57Co forms an excited state of the 57Fe nucleus, which in turn decays to the ground state with the emission of a gamma ray. Measurement of the gamma-ray spectrum provides information about the chemical state of the iron atom in the sample.

Related Research Articles

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Natural tantalum (73Ta) consists of two stable isotopes: 181Ta (99.988%) and 180m
Ta
 (0.012%).

Naturally occurring lutetium (71Lu) is composed of one stable isotope 175Lu and one long-lived radioisotope, 176Lu with a half-life of 37 billion years. Forty radioisotopes have been characterized, with the most stable, besides 176Lu, being 174Lu with a half-life of 3.31 years, and 173Lu with a half-life of 1.37 years. All of the remaining radioactive isotopes have half-lives that are less than 9 days, and the majority of these have half-lives that are less than half an hour. This element also has 18 meta states, with the most stable being 177mLu, 174mLu and 178mLu.

Naturally occurring ytterbium (70Yb) is composed of seven stable isotopes: 168Yb, 170Yb–174Yb, and 176Yb, with 174Yb being the most abundant. 30 radioisotopes have been characterized, with the most stable being 169Yb with a half-life of 32.014 days, 175Yb with a half-life of 4.185 days, and 166Yb with a half-life of 56.7 hours. All of the remaining radioactive isotopes have half-lives that are less than 2 hours, and the majority of these have half-lives that are less than 20 minutes. This element also has 18 meta states, with the most stable being 169mYb.

Naturally occurring cerium (58Ce) is composed of 4 stable isotopes: 136Ce, 138Ce, 140Ce, and 142Ce, with 140Ce being the most abundant and the only one theoretically stable; 136Ce, 138Ce, and 142Ce are predicted to undergo double beta decay but this process has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being 144Ce, with a half-life of 284.893 days; 139Ce, with a half-life of 137.640 days and 141Ce, with a half-life of 32.501 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days and the majority of these have half-lives that are less than 10 minutes. This element also has 10 meta states.

<span class="mw-page-title-main">Isotopes of lanthanum</span> Isotopes

Naturally occurring lanthanum (57La) is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138La, with a half-life of 1.02×1011 years; 137La, with a half-life of 60,000 years and 140La, with a half-life of 1.6781 days. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these have half-lives that are less than 1 minute. This element also has 12 nuclear isomers, the longest-lived of which is 132mLa, with a half-life of 24.3 minutes. Lighter isotopes mostly decay to isotopes of barium and heavy ones mostly decay to isotopes of cerium. 138La can decay to both.

Antimony (51Sb) occurs in two stable isotopes, 121Sb and 123Sb. There are 37 artificial radioactive isotopes, the longest-lived of which are 125Sb, with a half-life of 2.75856 years; 124Sb, with half-life 60.2 days; and 126Sb, with half-life 12.35 days. All other isotopes have half-lives less than 4 days, most less than an hour. There are also many isomers, the longest-lived of which is 120m1Sb with half-life 5.76 days.

Indium (49In) consists of two primordial nuclides, with the most common (~ 95.7%) nuclide (115In) being measurably though weakly radioactive. Its spin-forbidden decay has a half-life of 4.41×1014 years, much longer than the currently accepted age of the Universe.

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Naturally occurring rhodium (45Rh) is composed of only one stable isotope, 103Rh. The most stable radioisotopes are 101Rh with a half-life of 3.3 years, 102Rh with a half-life of 207 days, and 99Rh with a half-life of 16.1 days. Thirty other radioisotopes have been characterized with atomic weights ranging from 88.949 u (89Rh) to 121.943 u (122Rh). Most of these have half-lives that are less than an hour except 100Rh and 105Rh. There are also numerous meta states with the most stable being 102mRh (0.141 MeV) with a half-life of about 3.7 years and 101mRh (0.157 MeV) with a half-life of 4.34 days.

Naturally occurring niobium (41Nb) is composed of one stable isotope (93Nb). The most stable radioisotope is 92Nb with a half-life of 34.7 million years. The next longest-lived niobium isotopes are 94Nb and 91Nb with a half-life of 680 years. There is also a meta state of 93Nb at 31 keV whose half-life is 16.13 years. Twenty-seven other radioisotopes have been characterized. Most of these have half-lives that are less than two hours, except 95Nb, 96Nb and 90Nb. The primary decay mode before stable 93Nb is electron capture and the primary mode after is beta emission with some neutron emission occurring in 104–110Nb.

Natural yttrium (39Y) is composed of a single isotope yttrium-89. The most stable radioisotopes are 88Y, which has a half-life of 106.6 days, and 91Y, with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except 87Y, which has a half-life of 79.8 hours, and 90Y, with 64 hours. The dominant decay mode below the stable 89Y is electron capture and the dominant mode after it is beta emission. Thirty-five unstable isotopes have been characterized.

Naturally occurring nickel (28Ni) is composed of five stable isotopes; 58
Ni
, 60
Ni
, 61
Ni
, 62
Ni
 and 64
Ni
, with 58
Ni
 being the most abundant. 26 radioisotopes have been characterised with the most stable being 59
Ni
 with a half-life of 76,000 years, 63
Ni
 with a half-life of 100.1 years, and 56
Ni
 with a half-life of 6.077 days. All of the remaining radioactive isotopes have half-lives that are less than 60 hours and the majority of these have half-lives that are less than 30 seconds. This element also has 8 meta states.

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Naturally occurring vanadium (23V) is composed of one stable isotope 51V and one radioactive isotope 50V with a half-life of 2.71×1017 years. 24 artificial radioisotopes have been characterized (in the range of mass number between 40 and 65) with the most stable being 49V with a half-life of 330 days, and 48V with a half-life of 15.9735 days. All of the remaining radioactive isotopes have half-lives shorter than an hour, the majority of them below 10 seconds, the least stable being 42V with a half-life shorter than 55 nanoseconds, with all of the isotopes lighter than it, and none of the heavier, have unknown half-lives. In 4 isotopes, metastable excited states were found (including 2 metastable states for 60V), which adds up to 5 meta states.

Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-seven radioisotopes have been characterized, with the most stable being 46Sc with a half-life of 83.8 days, 47Sc with a half-life of 3.35 days, and 48Sc with a half-life of 43.7 hours and 44Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound 39Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being 44m2Sc.

Naturally occurring titanium (22Ti) is composed of five stable isotopes; 46Ti, 47Ti, 48Ti, 49Ti and 50Ti with 48Ti being the most abundant. Twenty-one radioisotopes have been characterized, with the most stable being 44Ti with a half-life of 60 years, 45Ti with a half-life of 184.8 minutes, 51Ti with a half-life of 5.76 minutes, and 52Ti with a half-life of 1.7 minutes. All of the remaining radioactive isotopes have half-lives that are less than 33 seconds, and the majority of these have half-lives that are less than half a second.

Berkelium (97Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are twenty known radioisotopes, from 233Bk and 233Bk to 253Bk, and six nuclear isomers. The longest-lived isotope is 247Bk with a half-life of 1,380 years.

Fermium (100Fm) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered was 255Fm in 1952. 250Fm was independently synthesized shortly after the discovery of 255Fm. There are 20 known radioisotopes ranging in atomic mass from 241Fm to 260Fm, and 4 nuclear isomers, 247mFm, 250mFm, 251mFm, and 253mFm. The longest-lived isotope is 257Fm with a half-life of 100.5 days, and the longest-lived isomer is 247mFm with a half-life of 5.1 seconds.

Mendelevium (101Md) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 256Md in 1955. There are 17 known radioisotopes, ranging in atomic mass from 244Md to 260Md, and 5 isomers. The longest-lived isotope is 258Md with a half-life of 51.3 days, and the longest-lived isomer is 258mMd with a half-life of 57 minutes.

References

  1. 1 2 3 4 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ↑ "Standard Atomic Weights: Cobalt". CIAAW. 2017.
  3. ↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN   1365-3075.
  4. ↑ Diaz, L. E. "Cobalt-57: Production". JPNM Physics Isotopes. University of Harvard. Archived from the original on 2000-10-31. Retrieved 2013-11-15.
  5. ↑ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  6. ↑ Bouchet, P.; Danziger, I.J.; Lucy, L.B. (September 1991). "Bolometric Light Curve of SN 1987A: Results from Day 616 to 1316 After Outburst". The Astronomical Journal. 102 (3): 1135–1146. doi:10.1086/115939 – via Astrophysics Data System.
  7. ↑ Diaz, L. E. "Cobalt-57: Uses". JPNM Physics Isotopes. University of Harvard. Archived from the original on 2011-06-11. Retrieved 2010-09-13.
  8. ↑ "Properties of Cobalt-60". Radioactive Isotopes. Retrieved 2022-12-09.
  9. ↑ "Beneficial Uses of Cobalt-60". INTERNATIONAL IRRADIATION ASSOCIATION. Retrieved 2022-12-09.
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