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) ^{[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
⁴²Cr	24	18	42.00643(32)#	14(3) ms [13(+4-2) ms]	β⁺ (>99.9%)	⁴²V	0+
⁴²Cr	24	18	42.00643(32)#	14(3) ms [13(+4-2) ms]	2p (<.1%)	⁴⁰Ti	0+
⁴³Cr	24	19	42.99771(24)#	21.6(7) ms	β⁺ (71%)	⁴³V	(3/2+)
					β⁺, p (23%)	⁴²Ti
					β⁺, 2p (6%)	⁴¹Sc
					β⁺, α (<.1%)	³⁹Sc
⁴⁴Cr	24	20	43.98555(5)#	54(4) ms [53(+4-3) ms]	β⁺ (93%)	⁴⁴V	0+
⁴⁴Cr	24	20	43.98555(5)#	54(4) ms [53(+4-3) ms]	β⁺, p (7%)	⁴³Ti	0+
⁴⁵Cr	24	21	44.97964(54)	50(6) ms	β⁺ (73%)	⁴⁵V	7/2−#
⁴⁵Cr	24	21	44.97964(54)	50(6) ms	β⁺, p (27%)	⁴⁴Ti	7/2−#
^45mCr	50(100)# keV			1# ms	IT	⁴⁵Cr	3/2+#
^45mCr	50(100)# keV			1# ms	β⁺	⁴⁵V	3/2+#
⁴⁶Cr	24	22	45.968359(21)	0.26(6) s	β⁺	⁴⁶V	0+
⁴⁷Cr	24	23	46.962900(15)	500(15) ms	β⁺	⁴⁷V	3/2−
⁴⁸Cr	24	24	47.954032(8)	21.56(3) h	β⁺	⁴⁸V	0+
⁴⁹Cr	24	25	48.9513357(26)	42.3(1) min	β⁺	⁴⁹V	5/2−
⁵⁰Cr	24	26	49.9460442(11)	Observationally Stable^{[n 8]}			0+	0.04345(13)	0.04294–0.04345
⁵¹Cr	24	27	50.9447674(11)	27.7025(24) d	EC	⁵¹V	7/2−
⁵²Cr	24	28	51.9405075(8)	Stable			0+	0.83789(18)	0.83762–0.83790
⁵³Cr	24	29	52.9406494(8)	Stable			3/2−	0.09501(17)	0.09501–0.09553
⁵⁴Cr	24	30	53.9388804(8)	Stable			0+	0.02365(7)	0.02365–0.02391
⁵⁵Cr	24	31	54.9408397(8)	3.497(3) min	β⁻	⁵⁵Mn	3/2−
⁵⁶Cr	24	32	55.9406531(20)	5.94(10) min	β⁻	⁵⁶Mn	0+
⁵⁷Cr	24	33	56.943613(2)	21.1(10) s	β⁻	⁵⁷Mn	(3/2−)
⁵⁸Cr	24	34	57.94435(22)	7.0(3) s	β⁻	⁵⁸Mn	0+
⁵⁹Cr	24	35	58.94859(26)	460(50) ms	β⁻	⁵⁹Mn	5/2−#
^59mCr	503.0(17) keV			96(20) μs			(9/2+)
⁶⁰Cr	24	36	59.95008(23)	560(60) ms	β⁻	⁶⁰Mn	0+
⁶¹Cr	24	37	60.95472(27)	261(15) ms	β⁻ (>99.9%)	⁶¹Mn	5/2−#
⁶¹Cr	24	37	60.95472(27)	261(15) ms	β⁻, n (<.1%)	⁶⁰Mn	5/2−#
⁶²Cr	24	38	61.95661(36)	199(9) ms	β⁻ (>99.9%)	⁶²Mn	0+
⁶²Cr	24	38	61.95661(36)	199(9) ms	β⁻, n	⁶¹Mn	0+
⁶³Cr	24	39	62.96186(32)#	129(2) ms	β⁻	⁶³Mn	(1/2−)#
⁶³Cr	24	39	62.96186(32)#	129(2) ms	β⁻, n	⁶²Mn	(1/2−)#
⁶⁴Cr	24	40	63.96441(43)#	43(1) ms	β⁻	⁶⁴Mn	0+
⁶⁵Cr	24	41	64.97016(54)#	27(3) ms	β⁻	⁶⁵Mn	(1/2−)#
⁶⁶Cr	24	42	65.97338(64)#	10(6) ms	β⁻	⁶⁶Mn	0+
⁶⁷Cr	24	43	66.97955(75)#	10# ms [>300 ns]	β⁻	⁶⁷Mn	1/2−#
⁶⁸Cr^[5]	24	44	67.98316(54)#	10# ms (>620 ns)	β⁻?^{[n 9]}	⁶⁸Mn	0+
					β⁻, n?^{[n 9]}	⁶⁷Mn
					β⁻, 2n?^{[n 9]}	⁶⁶Mn
⁶⁹Cr^[6]	24	45	68.98966(54)#	6# ms (>620 ns)	β⁻?^{[n 9]}	⁶⁹Mn	7/2+#
					β⁻, n?^{[n 9]}	⁶⁸Mn
					β⁻, 2n?^{[n 9]}	⁶⁷Mn
⁷⁰Cr^[6]	24	46	69.99395(64)#	6# ms (>620 ns)	β⁻?^{[n 9]}	⁷⁰Mn	0+
					β⁻, n?^{[n 9]}	⁶⁹Mn
					β⁻, 2n?^{[n 9]}	⁶⁸Mn
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.
^ Suspected of decaying by double electron capture to ⁵⁰Ti with a half-life of no less than 1.3×10¹⁸ a
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.

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.^[7]

External links

Chromium isotopes data from The Berkeley Laboratory Isotopes Project's

References

^ 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.
^ Tarasov, O. B.; et al. (April 2009). "Evidence for a Change in the Nuclear Mass Surface with the Discovery of the Most Neutron-Rich Nuclei with 17 ≤ Z ≤ 25". Physical Review Letters. 102 (14): 142501. arXiv:0903.1975. Bibcode:2009PhRvL.102n2501T. doi:10.1103/PhysRevLett.102.142501. PMID 19392430. S2CID 42329617. Retrieved 3 January 2023.
^ ^a ^b Tarasov, O. B.; et al. (May 2013). "Production cross sections from 82 Se fragmentation as indications of shell effects in neutron-rich isotopes close to the drip-line". Physical Review C. 87 (5): 054612. arXiv:1303.7164. Bibcode:2013PhRvC..87e4612T. doi:10.1103/PhysRevC.87.054612.
^ "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.

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

[TMS-7] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-8] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[9] Modes of decay:

EC: Electron capture

IT: Isomeric transition

p: Proton emission

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

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

[12] Suspected of decaying by double electron capture to ⁵⁰Ti with a half-life of no less than 1.3×10¹⁸ a

[decay_mode_1-14] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.

[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.

[13] Tarasov, O. B.; et al. (April 2009). "Evidence for a Change in the Nuclear Mass Surface with the Discovery of the Most Neutron-Rich Nuclei with 17 ≤ Z ≤ 25". Physical Review Letters. 102 (14): 142501. arXiv:0903.1975. Bibcode:2009PhRvL.102n2501T. doi:10.1103/PhysRevLett.102.142501. PMID 19392430. S2CID 42329617. Retrieved 3 January 2023.

[Tarasov_1-15] Tarasov, O. B.; et al. (May 2013). "Production cross sections from 82 Se fragmentation as indications of shell effects in neutron-rich isotopes close to the drip-line". Physical Review C. 87 (5): 054612. arXiv:1303.7164. Bibcode:2013PhRvC..87e4612T. doi:10.1103/PhysRevC.87.054612.

[16] "Chromium-51".

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