Isotopes of chromium

Isotopes of chromium (₂₄Cr)
γ	–
Standard atomic weight Ar°(Cr)
	51.9961±0.0006; 51.996±0.001 (abridged);
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Naturally occurring chromium (₂₄Cr) is composed of four stable isotopes; ⁵⁰Cr, ⁵²Cr, ⁵³Cr, and ⁵⁴Cr with ⁵²Cr being the most abundant (83.789% natural abundance). ⁵⁰Cr is suspected of decaying by β⁺β⁺ to ⁵⁰Ti with a half-life of (more than) 1.8×10¹⁷ years. Twenty-two radioisotopes, all of which are entirely synthetic, have been characterized, the most stable being ⁵¹Cr with a half-life of 27.7 days. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority of these have half-lives that are less than 1 minute. This element also has two meta states, ^45mCr, the more stable one, and ^59mCr, the least stable isotope or isomer.

⁵³Cr is the radiogenic decay product of ⁵³Mn. Chromium isotopic contents are typically combined with manganese isotopic contents and have found application in isotope geology. Mn-Cr isotope ratios reinforce the evidence from ²⁶Al and ¹⁰⁷Pd for the early history of the Solar System. Variations in ⁵³Cr/⁵²Cr and Mn/Cr ratios from several meteorites indicate an initial ⁵³Mn/⁵⁵Mn ratio that suggests Mn-Cr isotope systematics must result from in-situ decay of ⁵³Mn in differentiated planetary bodies. Hence ⁵³Cr provides additional evidence for nucleosynthetic processes immediately before coalescence of the Solar System. The same isotope is preferentially involved in certain leaching reactions, thereby allowing its abundance in seawater sediments to be used as a proxy for atmospheric oxygen concentrations.^[4]

The isotopes of chromium range from ⁴²Cr to ⁷⁰Cr. The primary decay mode before the most abundant stable isotope, ⁵²Cr, is electron capture and the primary mode after is beta decay.

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]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy^{[n 4]}			Half-life^[1] ^{[n 4]}	Decay mode^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity^[1] ^{[n 7]}^{[n 4]}	Normal proportion^[1]	Range of variation
⁴²Cr	24	18	42.00758(32)#	13.3(10) ms	β⁺ (94.4%)	⁴²V	0+
⁴²Cr	24	18	42.00758(32)#	13.3(10) ms	β⁺, p (5.6%)	⁴¹Ti	0+
⁴³Cr	24	19	42.99789(22)#	21.1(3) ms	β⁺, p (79.3%)	⁴²Ti	(3/2+)
					β⁺, 2p (11.6%)	⁴¹Sc
					β⁺ (8.97%)	⁴³V
					β⁺, 3p (0.13%)	⁴⁰Ca
⁴⁴Cr	24	20	43.985591(55)	42.8(6) ms	β⁺ (88%)	⁴⁴V	0+
⁴⁴Cr	24	20	43.985591(55)	42.8(6) ms	β⁺, p (12%)	⁴³Ti	0+
⁴⁵Cr	24	21	44.979050(38)	60.9(4) ms	β⁺ (65.6%)	⁴⁵V	7/2−#
⁴⁵Cr	24	21	44.979050(38)	60.9(4) ms	β⁺, p (34.4%)	⁴⁴Ti	7/2−#
^45mCr^{[n 8]}	107(1) keV			>80 μs	IT	⁴⁵Cr	(3/2)
⁴⁶Cr	24	22	45.968361(12)	224.3(13) ms	β⁺	⁴⁶V	0+
⁴⁷Cr	24	23	46.9628950(56)	461.6(15) ms	β⁺	⁴⁷V	3/2−
⁴⁸Cr	24	24	47.9540294(78)	21.56(3) h	β⁺	⁴⁸V	0+
⁴⁹Cr	24	25	48.9513337(24)	42.3(1) min	β⁺	⁴⁹V	5/2−
⁵⁰Cr	24	26	49.94604221(10)	Observationally Stable^{[n 9]}			0+	0.04345(13)
⁵¹Cr	24	27	50.94476539(18)	27.7015(11) d	EC	⁵¹V	7/2−
⁵²Cr	24	28	51.94050471(12)	Stable			0+	0.83789(18)
⁵³Cr	24	29	52.94064630(12)	Stable			3/2−	0.09501(17)
⁵⁴Cr	24	30	53.93887736(14)	Stable			0+	0.02365(7)
⁵⁵Cr	24	31	54.94083664(25)	3.497(3) min	β⁻	⁵⁵Mn	3/2−
⁵⁶Cr	24	32	55.94064898(62)	5.94(10) min	β⁻	⁵⁶Mn	0+
⁵⁷Cr	24	33	56.9436121(20)	21.1(10) s	β⁻	⁵⁷Mn	(3/2)−
⁵⁸Cr	24	34	57.9441845(32)	7.0(3) s	β⁻	⁵⁸Mn	0+
⁵⁹Cr	24	35	58.94834543(72)	1.05(9) s	β⁻	⁵⁹Mn	(1/2−)
^59mCr	502.7(11) keV			96(20) μs	IT	⁵⁹Cr	(9/2+)
⁶⁰Cr	24	36	59.9496417(12)	490(10) ms	β⁻	⁶⁰Mn	0+
⁶¹Cr	24	37	60.9543781(20)	243(9) ms	β⁻	⁶¹Mn	(5/2−)
⁶²Cr	24	38	61.9561429(37)	206(12) ms	β⁻	⁶²Mn	0+
⁶³Cr	24	39	62.961161(78)	129(2) ms	β⁻	⁶³Mn	1/2−#
⁶⁴Cr	24	40	63.96389(32)	43(1) ms	β⁻	⁶⁴Mn	0+
⁶⁵Cr	24	41	64.96961(22)#	27.5(21) ms	β⁻	⁶⁵Mn	1/2−#
⁶⁶Cr	24	42	65.97301(32)#	23.8(18) ms	β⁻	⁶⁶Mn	0+
⁶⁷Cr	24	43	66.97931(43)#	11# ms [>300 ns]			1/2−#
⁶⁸Cr	24	44	67.98316(54)#	10# ms [>620 ns]			0+
⁶⁹Cr	24	45	68.98966(54)#	6# ms [>620 ns]			7/2+#
⁷⁰Cr	24	46	69.99395(64)#	6# ms [>620 ns]			0+
This table header & footer: view

^ ^mCr – 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

p: Proton emission
^ Bold symbol as daughter – Daughter product is stable.
^ ( ) spin value – Indicates spin with weak assignment arguments.
^ Order of ground state and isomer is uncertain.
^ Suspected of decaying by double β⁺ decay to ⁵⁰Ti with a half-life of no less than 1.3×10¹⁸ years

Chromium-51

Chromium-51 is a synthetic radioactive isotope of chromium having a half-life of 27.7 days and decaying by electron capture with emission of gamma rays (0.32 MeV); it is used to label red blood cells for measurement of mass or volume, survival time, and sequestration studies, for the diagnosis of gastrointestinal bleeding, and to label platelets to study their survival. It has a role as a radioactive label. Chromium Cr-51 has been used as a radioactive label for decades. It is used as a diagnostic radiopharmaceutical agent in nephrology to determine glomerular filtration rate, and in hematology to determine red blood cell volume or mass, study the red blood cell survival time and evaluate blood loss.^[6]

External links

Chromium isotopes data from The Berkeley Laboratory Isotopes Project's

References

^ ^a ^b ^c ^d ^e 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.
^ "Standard Atomic Weights: Chromium". CIAAW. 1983.
^ 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.
^ R. Frei; C. Gaucher; S. W. Poulton; D. E. Canfield (2009). "Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes". Nature. 461 (7261): 250–3. Bibcode:2009Natur.461..250F. doi:10.1038/nature08266. PMID 19741707. S2CID 4373201.
^ 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.
^ "Chromium-51".

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.
"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
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.

[5] Cr – Excited nuclear isomer.

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

[TMS-8] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-9] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[10] Modes of decay:

EC: Electron capture

IT: Isomeric transition

p: Proton emission

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

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

[order-13] Order of ground state and isomer is uncertain.

[14] Suspected of decaying by double β⁺ decay to ⁵⁰Ti with a half-life of no less than 1.3×10¹⁸ years

[NUBASE2020-1] 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: Chromium". CIAAW. 1983.

[CIAAW2021-3] 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.

[52Cr-Frei-4] R. Frei; C. Gaucher; S. W. Poulton; D. E. Canfield (2009). "Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes". Nature. 461 (7261): 250–3. Bibcode:2009Natur.461..250F. doi:10.1038/nature08266. PMID 19741707. S2CID 4373201.

[AME2020_II-6] 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.

[15] "Chromium-51".

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