Isotopes of cobalt

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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 (271.81 days), ⁵⁶Co (77.24 days), and ⁵⁸Co (70.84 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 8.85 hours.

Quick facts Main isotopes, Decay ...

Isotopes of cobalt (₂₇Co)

Main isotopes^[1]			Decay
Isotope	abundance	half-life (t_1/2)	mode	product
⁵⁶Co	synth	77.24 d	β⁺	⁵⁶Fe
⁵⁷Co	synth	271.81 d	ε	⁵⁷Fe
⁵⁸Co	synth	70.84 d	β⁺	⁵⁸Fe
⁵⁹Co	100%	stable
⁶⁰Co	trace	5.2714 y	β⁻	⁶⁰Ni

Standard atomic weight A_r°(Co)

58.933194±0.000003^[2]
58.933±0.001 (abridged)^[3]

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 to iron isotopes, and the main mode of decay for those with greater mass is beta decay to nickel isotopes.

List of isotopes

More information Nuclide, Z ...

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da)^[4] ^{[n 2]}^{[n 3]}	Discovery year^[5]^[6]	Half-life^[1] ^{[n 4]}	Decay mode^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity^[1] ^{[n 7]}^{[n 4]}	Isotopic abundance
Nuclide ^{[n 1]}	Excitation energy^{[n 4]}			Discovery year^[5]^[6]	Half-life^[1] ^{[n 4]}	Decay mode^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity^[1] ^{[n 7]}^{[n 4]}	Isotopic abundance
⁵⁰Co	27	23	49.98112(14)	1987	38.8(2) ms	β⁺, p (70.5%)	⁴⁹Mn	(6+)
						β⁺ (29.5%)	⁵⁰Fe
						β⁺, 2p?	⁴⁸Cr
⁵¹Co	27	24	50.970647(52)	1987	68.8(19) ms	β⁺ (96.2%)	⁵¹Fe	7/2−
⁵¹Co	27	24	50.970647(52)	1987	68.8(19) ms	β⁺, p (<3.8%)	⁵⁰Mn	7/2−
⁵²Co	27	25	51.9631302(57)	1987	111.7(21) ms	β⁺	⁵²Fe	6+
⁵²Co	27	25	51.9631302(57)	1987	111.7(21) ms	β⁺, p?	⁵¹Mn	6+
^52mCo	376(9) keV			2017	102(5) ms	β⁺	⁵²Fe	2+
						IT?	⁵²Co
						β⁺, p?	⁵¹Mn
⁵³Co	27	26	52.9542033(19)	1970	244.6(28) ms	β⁺	⁵³Fe	7/2−#
^53mCo	3174.3(9) keV			1970	250(10) ms	β⁺? (~98.5%)	⁵³Fe	(19/2−)
^53mCo	3174.3(9) keV			1970	250(10) ms	p (~1.5%)	⁵²Fe	(19/2−)
⁵⁴Co	27	27	53.94845908(38)	1952	193.27(6) ms	β⁺	⁵⁴Fe	0+
^54mCo	197.57(10) keV			1967	1.48(2) min	β⁺	⁵⁴Fe	7+
⁵⁵Co	27	28	54.94199642(43)	1938	17.53(3) h	β⁺	⁵⁵Fe	7/2−
⁵⁶Co	27	29	55.93983803(51)	1941	77.236(26) d	β⁺	⁵⁶Fe	4+
⁵⁷Co	27	30	56.93628982(55)	1941	271.811(32) d	EC	⁵⁷Fe	7/2−
⁵⁸Co	27	31	57.9357513(12)	1941	70.844(20) d	EC (85.21%)	⁵⁸Fe	2+
⁵⁸Co	27	31	57.9357513(12)	1941	70.844(20) d	β⁺ (14.79%)	⁵⁸Fe	2+
^58m1Co	24.95(6) keV			1950	8.853(23) h	IT (99.9988%)	⁵⁸Co	5+
^58m1Co	24.95(6) keV			1950	8.853(23) h	EC (0.00120%)	⁵⁸Fe	5+
^58m2Co	53.15(7) keV			1964	10.5(3) μs	IT	⁵⁸Co	4+
⁵⁹Co	27	32	58.93319352(43)	1923	Stable			7/2−	1.0000
⁶⁰Co	27	33	59.93381554(43)	1941	5.2714(6) y	β⁻	⁶⁰Ni	5+	trace
^60mCo	58.59(1) keV			1941	10.467(6) min	IT (99.75%)	⁶⁰Co	2+
^60mCo	58.59(1) keV			1941	10.467(6) min	β⁻ (0.25%)	⁶⁰Ni	2+
⁶¹Co	27	34	60.93247603(90)	1947	1.649(5) h	β⁻	⁶¹Ni	7/2−
⁶²Co	27	35	61.934058(20)	1949	1.54(10) min	β⁻	⁶²Ni	(2)+
^62mCo	22(5) keV			1949	13.86(9) min	β⁻ (>99.5%)	⁶²Ni	(5)+
^62mCo	22(5) keV			1949	13.86(9) min	IT (<0.5%)	⁶²Co	(5)+
⁶³Co	27	36	62.933600(20)	1960	26.9(4) s	β⁻	⁶³Ni	7/2−
⁶⁴Co	27	37	63.935810(21)	1969	300(30) ms	β⁻	⁶⁴Ni	1+
^64mCo	107(20) keV			2010	300# ms	β⁻?	⁶⁴Ni	5+#
^64mCo	107(20) keV			2010	300# ms	IT?	⁶⁴Co	5+#
⁶⁵Co	27	38	64.9364621(22)	1978	1.16(3) s	β⁻	⁶⁵Ni	(7/2)−
⁶⁶Co	27	39	65.939443(15)	1985	194(17) ms	β⁻	⁶⁶Ni	(1+)
⁶⁶Co	27	39	65.939443(15)	1985	194(17) ms	β⁻, n?	⁶⁵Ni	(1+)
^66m1Co	175.1(3) keV			1998	824(22) ns	IT	⁶⁶Co	(3+)
^66m2Co	642(5) keV			1998	>100 μs	IT	⁶⁶Co	(8−)
⁶⁷Co	27	40	66.9406096(69)	1985	329(28) ms	β⁻	⁶⁷Ni	(7/2−)
⁶⁷Co	27	40	66.9406096(69)	1985	329(28) ms	β⁻, n?	⁶⁶Ni	(7/2−)
^67mCo	491.55(11) keV			2008	496(33) ms	IT (>80%)	⁶⁷Co	(1/2−)
^67mCo	491.55(11) keV			2008	496(33) ms	β⁻	⁶⁷Ni	(1/2−)
⁶⁸Co	27	41	67.9445594(41)	1985	200(20) ms	β⁻	⁶⁸Ni	(7−)
⁶⁸Co	27	41	67.9445594(41)	1985	200(20) ms	β⁻, n?	⁶⁷Ni	(7−)
^68m1Co^{[n 8]}	150(150)# keV			2000	1.6(3) s	β⁻	⁶⁸Ni	(2−)
^68m1Co^{[n 8]}	150(150)# keV			2000	1.6(3) s	β⁻, n (>2.6%)	⁶⁷Ni	(2−)
^68m2Co	195(150)# keV			2010	101(10) ns	IT	⁶⁸Co	(1)
⁶⁹Co	27	42	68.945909(92)	1985	180(20) ms	β⁻	⁶⁹Ni	(7/2−)
⁶⁹Co	27	42	68.945909(92)	1985	180(20) ms	β⁻, n?	⁶⁸Ni	(7/2−)
^69mCo^{[n 8]}	170(90) keV			2015	750(250) ms	β⁻	⁶⁹Ni	1/2−#
⁷⁰Co	27	43	69.950053(12)	1985	508(7) ms	β⁻	⁷⁰Ni	(1+)
						β⁻, n?	⁶⁹Ni
						β⁻, 2n?	⁶⁸Ni
^70mCo^{[n 8]}	200(200)# keV			2000	112(7) ms	β⁻	⁷⁰Ni	(7−)
						IT?	⁷⁰Co
						β⁻, n?	⁶⁹Ni
						β⁻, 2n?	⁶⁸Ni
⁷¹Co	27	44	70.95237(50)	1992	80(3) ms	β⁻ (97%)	⁷¹Ni	(7/2−)
⁷¹Co	27	44	70.95237(50)	1992	80(3) ms	β⁻, n (3%)	⁷⁰Ni	(7/2−)
⁷²Co	27	45	71.95674(32)#	1992	51.5(3) ms	β⁻ (<96%)	⁷²Ni	(6−,7−)
						β⁻, n (>4%)	⁷¹Ni
						β⁻, 2n?	⁷⁰Ni
^72mCo^{[n 8]}	200(200)# keV			2016	47.8(5) ms	β⁻	⁷²Ni	(0+,1+)
⁷³Co	27	46	72.95924(32)#	1995	42.0(8) ms	β⁻ (94%)	⁷³Ni	(7/2−)
						β⁻, n (6%)	⁷²Ni
						β⁻, 2n?	⁷¹Ni
⁷⁴Co	27	47	73.96399(43)#	1995	31.3(13) ms	β⁻ (82%)	⁷⁴Ni	7−#
						β⁻, n (18%)	⁷³Ni
						β⁻, 2n?	⁷²Ni
⁷⁵Co	27	48	74.96719(43)#	1995	26.5(12) ms	β⁻ (>84%)	⁷⁵Ni	7/2−#
						β⁻, n (<16%)	⁷⁴Ni
						β⁻, 2n?	⁷³Ni
⁷⁶Co	27	49	75.97245(54)#	2010	23(6) ms	β⁻	⁷⁶Ni	(8−)
						β⁻, n?	⁷⁵Ni
						β⁻, 2n?	⁷⁴Ni
^76m1Co^{[n 8]}	100(100)# keV			2015	16(4) ms	β⁻	⁷⁶Ni	(1−)
^76m2Co	740(100)# keV			2015	2.99(27) μs	IT	⁷⁶Co	(3+)
⁷⁷Co	27	50	76.97648(64)#	2014	15(6) ms	β⁻	⁷⁷Ni	7/2−#
						β⁻, n?	⁷⁶Ni
						β⁻, 2n?	⁷⁵Ni
						β⁻, 3n?	⁷⁴Ni
⁷⁸Co	27	51	77.983 55(75)#	2017	11# ms [>410 ns]	β⁻?	⁷⁸Ni
⁷⁹Co^[7]	27	52		2026
⁸⁰Co^[7]	27	53		2026
This table header & footer: view

[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]
# – 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]
Order of ground state and isomer is uncertain.

| β⁻ | ⁷⁷Ni | rowspan=4|7/2−# | rowspan=4| |- | β⁻, n? | ⁷⁶Ni |- | β⁻, 2n? | ⁷⁵Ni |- | β⁻, 3n? | ⁷⁴Ni |-id=Cobalt-78 | ⁷⁸Co | style="text-align:right" | 27 | style="text-align:right" | 51 | 77.983 55(75)# | style="text-align:center" | 2015 | 11# ms
[>410 ns] | β⁻? | ⁷⁸Ni | | |-id=Cobalt-79 | ⁷⁹Co^[7] | style="text-align:right" | 27 | style="text-align:right" | 52 | | style="text-align:center" | 2014 | | | | | |-id=Cobalt-80 | ⁸⁰Co^[7] | style="text-align:right" | 27 | style="text-align:right" | 53 | | style="text-align:center" | 2017 | | | | | |-

! colspan="20" style="text-align:right; line-height:85%;" |

This table header & footer:

Stellar nucleosynthesis of cobalt-56

One of the terminal nuclear reactions in stars prior to supernova produces ⁵⁶Ni. ⁵⁶Ni then decays to ⁵⁶Co, which then decays to ⁵⁶Fe. These decays 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 68.6 days to 69.6 days.^[8] The rate at which the luminosity decreased closely matched that expected of exponential decay of ⁵⁶Co.

Cobalt-57

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.^[9]

⁵⁷Co is used as a source of gamma rays 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.

Cobalt-60

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.^{[citation needed]} 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 more usual.

Cobalt-60 (⁶⁰Co) is useful as an industrial gamma ray source also: uses for industrial cobalt include

Sterilization of medical supplies and medical waste
Radiation treatment of foods for sterilization (cold pasteurization)^[10]
Industrial radiography (e.g., weld integrity radiographs)
Density measurements (e.g., concrete density measurements)
Tank fill height switches

References

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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]
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.
[5]
FRIB Nuclear Data Group. "Discovery of Nuclides Project, Isotope Database". doi:10.11578/frib/2279152.
[6]
FRIB Nuclear Data Group. "Discovery of Nuclides Project, Isomer Database". doi:10.11578/frib/2572219.
[7]
Shimizu, Y; Rykaczewski, K P; Fukuda, N; Brewer, N T; Dillmann, I; Grzywacz, R K; Nishimura, S; Rasco, B C; Tain, J L; Suzuki, H; Takeda, H; Ahn, D S; Sumikama, T; Inabe, N; Yoshida, K; Ueno, H; Michimasa, S; Algora, A; Allmond, J M; Agramunt, J; Baba, H; Bae, S; Bruno, C G; Caballero-Folch, R; Calvino, F; Coleman-Smith, P J; Cortes, G; Davinson, T; Domingo-Pardo, C; Estrade, A; Go, S; Griffin, C J; Ha, J; Hall, O; Harkness-Brennan, L J; Heideman, J; Isobe, T; Kahl, D; Karny, M; Khiem, L H; King, T T; Kiss, G G; Korgul, A; Kubono, S; Labiche, M; Lazarus, I; Liang, J; Liu, J; Lorusso, G; Madurga, M; Matsui, K; Miernik, K; Montes, F; Morales, A I; Morrall, P; Nepal, N; Page, R D; Phong, V H; Piersa-Siłkowska, M; Prydderch, M; Pucknell, V F E; Rajabali, M M; Rubio, B; Saito, Y; Sakurai, H; Simpson, J; Singh, M; Stracener, D W; Tarifeño-Saldivia, A; Thomas, S L; Tolosa-Delgado, A; Wolinska-Cichocka, M; Woods, P J; Xu, X X; Yokoyama, R (6 March 2026). "Exploration of Neutron-Rich Isotopes around N = 50 via the In-Flight Fission of a 345 MeV/Nucleon 238U Beam". Progress of Theoretical and Experimental Physics. 2026 (3). doi:10.1093/ptep/ptag036.
[8]
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. Bibcode:1991AJ....102.1135B. doi:10.1086/115939 – via Astrophysics Data System.
[9]
Diaz, L. E. "Cobalt-57: Uses". JPNM Physics Isotopes. University of Harvard. Archived from the original on 2011-06-11. Retrieved 2010-09-13.
[10]
"Beneficial Uses of Cobalt-60". INTERNATIONAL IRRADIATION ASSOCIATION. Retrieved 2022-12-09.