Isotopes of cobalt

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 products before ⁵⁹Co are iron isotopes and the primary products after are nickel isotopes.

Standard atomic mass: 58.933195(5) u

1 Use of cobalt radioisotopes in medicine
2 Industrial uses for radioactive isotopes
3 Table
- 3.1 Notes
4 References

Use of cobalt radioisotopes in medicine

Cobalt-60 (Co-60 or ⁶⁰Co) 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.

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.^[1]

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 quantity, and high activity—by simply exposing natural cobalt to neutrons in a reactor for a given time. It is used for

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); and
tank fill height switches.

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)^[2]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life	decay mode(s)^[2]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
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) a	β^-	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-#

^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
^ Bold for stable isotopes

Notes

Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

^ L. E. Diaz. "Cobalt-57: Uses". JPNM Physics Isotopes. University of Harvard. http://www.med.harvard.edu/JPNM/physics/isotopes/Co/Co57/uses.html. Retrieved 2010-09-13.
^ http://www.nucleonica.net/unc.aspx

Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683. http://www.iupac.org/publications/pac/75/6/0683/pdf/.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. http://iupac.org/publications/pac/78/11/2051/pdf/. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. Retrieved September 2005.
- David R. Lide (ed.), orman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.

Isotopes of iron	Isotopes of cobalt	Isotopes of nickel
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