Isotopes of cobalt

Main isotopes of cobalt (₂₇Co)
Standard atomic weight Ar, standard(Co)	58.933194(3)
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Naturally occurring cobalt (₂₇Co) is composed of a single stable isotope, ⁵⁹Co. Twenty-eight radioisotopes have been characterized with the most stable being ⁶⁰Co with a half-life of 5.2714 years, ⁵⁷Co with a half-life of 271.8 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 products before ⁵⁹Co are iron isotopes and the primary products after are nickel isotopes.

Radioactive isotopes can be produced by various nuclear reactions. For example, the isotope ⁵⁷Co is produced by cyclotron irradiation of iron. The principal reaction involved is the (d,n) reaction ⁵⁶Fe + ²H → n + ⁵⁷Co.^[3]

List of isotopes[]

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 4]}			Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Normal proportion	Range of variation
⁴⁷Co	27	20	47.01149(54)#				7/2−#
⁴⁸Co	27	21	48.00176(43)#		p	⁴⁷Fe	6+#
⁴⁹Co	27	22	48.98972(28)#	<35 ns	p (>99.9%)	⁴⁸Fe	7/2−#
⁴⁹Co	27	22	48.98972(28)#	<35 ns	β⁺ (<.1%)	⁴⁹Fe	7/2−#
⁵⁰Co	27	23	49.98154(18)#	44(4) ms	β⁺, p (54%)	⁴⁹Mn	(6+)
⁵⁰Co	27	23	49.98154(18)#	44(4) ms	β⁺ (46%)	⁵⁰Fe	(6+)
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+#
^52mCo	380(100)# keV			104(11)# ms	IT	⁵²Co	2+#
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−)
^53mCo	3197(29) keV			247(12) ms	p (1.5%)	⁵²Fe	(19/2−)
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	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	27	33	59.9338171(7)	5.2713(8) y	β⁻, γ	⁶⁰Ni	5+
^60mCo	58.59(1) keV			10.467(6) min	IT (99.76%)	⁶⁰Co	2+
^60mCo	58.59(1) keV			10.467(6) min	β⁻ (.24%)	⁶⁰Ni	2+
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+
^62mCo	22(5) keV			13.91(5) min	IT (1%)	⁶²Co	5+
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−#
⁶⁹Co	27	42	68.94632(36)	227(13) ms	β⁻, n (<.1%)	⁶⁸Ni	7/2−#
⁷⁰Co	27	43	69.9510(9)	119(6) ms	β⁻ (>99.9%)	⁷⁰Ni	(6-)
⁷⁰Co	27	43	69.9510(9)	119(6) ms	β⁻, n (<.1%)	⁶⁹Ni	(6-)
^70mCo	200(200)# keV			500(180) ms			(3+)
⁷¹Co	27	44	70.9529(9)	97(2) ms	β⁻ (>99.9%)	⁷¹Ni	7/2−#
⁷¹Co	27	44	70.9529(9)	97(2) ms	β⁻, n (<.1%)	⁷⁰Ni	7/2−#
⁷²Co	27	45	71.95781(64)#	62(3) ms	β⁻ (>99.9%)	⁷²Ni	(6- ,7-)
⁷²Co	27	45	71.95781(64)#	62(3) ms	β⁻, n (<.1%)	⁷¹Ni	(6- ,7-)
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−#
This table header & footer: view

^ ^mCo – Excited nuclear isomer.
^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
^ ^a ^b ^c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
^ Modes of decay:

EC: Electron capture

IT: Isomeric transition

n: Neutron emission

p: Proton emission
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.

Use of cobalt radioisotopes in medicine []

Cobalt-57 (⁵⁷Co or Co-57) 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.^[4]

Cobalt-60 (⁶⁰Co or Co-60) is a radioactive metal that 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 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.

Industrial uses for radioactive isotopes[]

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

Sterilization of medical supplies and medical waste
Radiation treatment of foods for sterilization (cold pasteurization)
Industrial radiography (e.g., weld integrity radiographs)
Density measurements (e.g., concrete density measurements)
Tank fill height switches.

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

References[]

^ "Standard Atomic Weights: Cobalt". CIAAW. 2017.
^ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
^ Diaz, L. E. "Cobalt-57: Production". JPNM Physics Isotopes. University of Harvard. Retrieved 2013-11-15.
^ Diaz, L. E. "Cobalt-57: Uses". JPNM Physics Isotopes. University of Harvard. Retrieved 2010-09-13.

Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary. {{cite journal}}: Cite uses deprecated parameter |lay-url= (help)
Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

[4] Co – Excited nuclear isomer.

[5] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-6] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-7] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[8] Modes of decay:

EC: Electron capture

IT: Isomeric transition

n: Neutron emission

p: Proton emission

[9] Bold symbol as daughter – Daughter product is stable.

[10] ( ) spin value – Indicates spin with weak assignment arguments.

[1] "Standard Atomic Weights: Cobalt". CIAAW. 2017.

[CIAAW2013-2] Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

[57Co-Diaz-production-3] Diaz, L. E. "Cobalt-57: Production". JPNM Physics Isotopes. University of Harvard. Retrieved 2013-11-15.

[57Co-Diaz-uses-11] Diaz, L. E. "Cobalt-57: Uses". JPNM Physics Isotopes. University of Harvard. Retrieved 2010-09-13.

[1]

[2]

[3]

[n 1]

[n 2]

[n 3]

[n 4]

[n 5]

[n 6]

[n 7]

[4]

EC:	Electron capture
IT:	Isomeric transition
n:	Neutron emission
p:	Proton emission