Isotopes of chromium

{{Short description|none}} {{Infobox chromium isotopes}} 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). Twenty-two radioisotopes, all synthetic, have been characterized, the most stable being ⁵¹Cr with a half-life of 27.70 days. All of the remaining radioactive isotopes have half-lives less than a day and for the majority of these less than a minute. This element also has two very short-lived meta states: ^45mCr and ^59mCr.

⁵³Cr is the radiogenic decay product of ⁵³Mn. Chromium and manganese are found together sufficiently for measurement of both to find 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 a non-zero initial ⁵³Mn/⁵⁵Mn ratio, implying that Cr isotopic variation 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.

Chromium isotope ratios also allow its abundance in seawater sediments to be used as a proxy for atmospheric oxygen concentrations, as rates of certain leaching reactions exhibit variation.<ref>{{cite journal | author = R. Frei |author2=C. Gaucher |author3=S. W. Poulton |author4=D. E. Canfield | year = 2009 | title = Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes | journal = Nature | volume = 461| issue = 7261| pages = 250–3 | doi = 10.1038/nature08266 | pmid = 19741707 | bibcode=2009Natur.461..250F |s2cid=4373201 }}</ref>

The known 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 == {{Anchor|Chromium-41}}

<!--Please delete anchor(s) from the list above or table below if adding a dedicated isotope section(s).-->

{{Isotopes table |symbol=Cr |refs=NUBASE2020, AME2020 II,<!-- updated 2024-10-27 --> IsotopeFRIB, IsomerFRIB |notes=m, unc(), hl#, mass#, exen#, spin(), spin#, daughter-st, EC, IT, p, discoveryname }} |-id=Chromium-42 | rowspan=2|⁴²Cr | rowspan=2 style="text-align:right" | 24 | rowspan=2 style="text-align:right" | 18 | rowspan=2|42.00758(32)# | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/42.pdf 1996] | rowspan=2|13.3(10)&nbsp;ms | β⁺ (94.4%) | ⁴²V | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺, p (5.6%) | ⁴¹Ti |-id=Chromium-43 | rowspan=4|⁴³Cr | rowspan=4 style="text-align:right" | 24 | rowspan=4 style="text-align:right" | 19 | rowspan=4|42.99789(22)# | rowspan=4 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/43.pdf 1992] | rowspan=4|21.1(3)&nbsp;ms | β⁺, p (79.3%) | ⁴²Ti | rowspan=4|(3/2+) | rowspan=4| | rowspan=4| |- | β⁺, 2p (11.6%) | ⁴¹Sc |- | β⁺ (8.97%) | ⁴³V |- | β⁺, 3p (0.13%) | '''⁴⁰Ca''' |-id=Chromium-44 | rowspan=2|⁴⁴Cr | rowspan=2 style="text-align:right" | 24 | rowspan=2 style="text-align:right" | 20 | rowspan=2|43.985591(55) | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/44.pdf 1987] | rowspan=2|42.8(6)&nbsp;ms | β⁺ (88%) | ⁴⁴V | rowspan=2|0+ | rowspan=2| | rowspan=2| |- | β⁺, p (12%) | ⁴³Ti |-id=Chromium-45 | rowspan=2|⁴⁵Cr | rowspan=2 style="text-align:right" | 24 | rowspan=2 style="text-align:right" | 21 | rowspan=2|44.979050(38) | rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/45.pdf 1974] | rowspan=2|60.9(4)&nbsp;ms | β⁺ (65.6%) | ⁴⁵V | rowspan=2|7/2−# | rowspan=2| | rowspan=2| |- | β⁺, p (34.4%) | ⁴⁴Ti |-id=Chromium-45m | style="text-indent:1em" | ^45mCr<ref group="n" name="order">Order of ground state and isomer is uncertain.</ref> | colspan="3" style="text-indent:2em" | 107(1)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/24/45Cr-1.pdf 2011] | >80&nbsp;μs | IT | ⁴⁵Cr | (3/2) | | |-id=Chromium-46 | ⁴⁶Cr | style="text-align:right" | 24 | style="text-align:right" | 22 | 45.9683549(28)<ref name="wang2022">{{cite journal |last1=Wang |first1=M. |last2=Zhang |first2=M. |last3=Zhou |first3=X. |last4=Zhang |first4=Y. H. |last5=Litvinov |first5=Yu. A. |last6=Xu |first6=H. S. |last7=Chen |first7=R. J. |last8=Deng |first8=H. Y. |last9=Fu |first9=C. Y. |last10=Ge |first10=W. W. |last11=Li |first11=H. F. |last12=Liao |first12=T. |last13=Litvinov |first13=S. A. |last14=Shuai |first14=P. |last15=Shi |first15=J. Y. |last16=Si |first16=M. |last17=Sidhu |first17=R. S. |last18=Song |first18=Y. N. |last19=Sun |first19=M. Z. |last20=Suzuki |first20=S. |last21=Wang |first21=Q. |last22=Xing |first22=Y. M. |last23=Xu |first23=X. |last24=Yamaguchi |first24=T. |last25=Yan |first25=X. L. |last26=Yang |first26=J. C. |last27=Yuan |first27=Y. J. |last28=Zeng |first28=Q. |last29=Zhou |first29=X. H. |title=B ρ -defined isochronous mass spectrometry: An approach for high-precision mass measurements of short-lived nuclei |journal=Physical Review C |date=1 November 2022 |volume=106 |issue=5 |article-number=L051301 |doi=10.1103/PhysRevC.106.L051301|arxiv=2211.01655 |bibcode=2022PhRvC.106e1301W }}</ref> | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/46.pdf 1972] | 224.3(13)&nbsp;ms | β⁺ | ⁴⁶V | 0+ | | |-id=Chromium-47 | ⁴⁷Cr | style="text-align:right" | 24 | style="text-align:right" | 23 | 46.9628950(56) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/47.pdf 1972] | 461.6(15)&nbsp;ms | β⁺ | ⁴⁷V | 3/2− | | |-id=Chromium-48 | ⁴⁸Cr | style="text-align:right" | 24 | style="text-align:right" | 24 | 47.9540294(78) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/48.pdf 1952] | 21.56(3)&nbsp;h | β⁺ | ⁴⁸V | 0+ | | |-id=Chromium-49 | ⁴⁹Cr | style="text-align:right" | 24 | style="text-align:right" | 25 | 48.9513337(24) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/49.pdf 1942] | 42.3(1)&nbsp;min | β⁺ | ⁴⁹V | 5/2− | | |-id=Chromium-50 | ⁵⁰Cr | style="text-align:right" | 24 | style="text-align:right" | 26 | 49.94604221(10) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/50.pdf 1930] | colspan=3 align=center|'''Observationally Stable'''<ref group="n">Suspected of decaying by double β⁺ decay to '''⁵⁰Ti''' with a half-life of no less than 1.3{{e|18}}&nbsp;years</ref> | 0+ | 0.04345(13) | |-id=Chromium-51 | ⁵¹Cr | style="text-align:right" | 24 | style="text-align:right" | 27 | 50.94476539(18) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/51.pdf 1940] | 27.7015(11)&nbsp;d | EC | '''⁵¹V''' | 7/2− | | |-id=Chromium-52 | ⁵²Cr | style="text-align:right" | 24 | style="text-align:right" | 28 | 51.94050471(12) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/52.pdf 1923] | colspan=3 align=center|'''Stable''' | 0+ | 0.83789(18) | |-id=Chromium-53 | ⁵³Cr | style="text-align:right" | 24 | style="text-align:right" | 29 | 52.94064630(12) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/53.pdf 1930] | colspan=3 align=center|'''Stable''' | 3/2− | 0.09501(17) | |-id=Chromium-54 | ⁵⁴Cr | style="text-align:right" | 24 | style="text-align:right" | 30 | 53.93887736(14) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/54.pdf 1930] | colspan=3 align=center|'''Stable''' | 0+ | 0.02365(7) | |-id=Chromium-55 | ⁵⁵Cr | style="text-align:right" | 24 | style="text-align:right" | 31 | 54.94083664(25) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/55.pdf 1952] | 3.497(3)&nbsp;min | β⁻ | '''⁵⁵Mn''' | 3/2− | | |-id=Chromium-56 | ⁵⁶Cr | style="text-align:right" | 24 | style="text-align:right" | 32 | 55.94064898(62) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/56.pdf 1960] | 5.94(10)&nbsp;min | β⁻ | ⁵⁶Mn | 0+ | | |-id=Chromium-57 | ⁵⁷Cr | style="text-align:right" | 24 | style="text-align:right" | 33 | 56.9436121(20) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/57.pdf 1978] | 21.1(10)&nbsp;s | β⁻ | ⁵⁷Mn | (3/2)− | | |-id=Chromium-58 | ⁵⁸Cr | style="text-align:right" | 24 | style="text-align:right" | 34 | 57.9441845(32) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/58.pdf 1980] | 7.0(3)&nbsp;s | β⁻ | ⁵⁸Mn | 0+ | | |-id=Chromium-59 | ⁵⁹Cr | style="text-align:right" | 24 | style="text-align:right" | 35 | 58.94834543(72) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/59.pdf 1980] | 1.05(9)&nbsp;s | β⁻ | ⁵⁹Mn | (1/2−) | | |-id=Chromium-59m | style="text-indent:1em" | ^59mCr | colspan="3" style="text-indent:2em" | 502.7(11)&nbsp;keV | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/isomers/abstracts/24/59Cr-1.pdf 1998] | 96(20)&nbsp;μs | IT | ⁵⁹Cr | (9/2+) | | |-id=Chromium-60 | ⁶⁰Cr | style="text-align:right" | 24 | style="text-align:right" | 36 | 59.9496417(12) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/60.pdf 1980] | 490(10)&nbsp;ms | β⁻ | ⁶⁰Mn | 0+ | | |-id=Chromium-61 | ⁶¹Cr | style="text-align:right" | 24 | style="text-align:right" | 37 | 60.9543781(20) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/61.pdf 1985] | 243(9)&nbsp;ms | β⁻ | ⁶¹Mn | (5/2−) | | |-id=Chromium-62 | ⁶²Cr | style="text-align:right" | 24 | style="text-align:right" | 38 | 61.9561429(37) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/62.pdf 1985] | 206(12)&nbsp;ms | β⁻ | ⁶²Mn | 0+ | | |-id=Chromium-63 | ⁶³Cr | style="text-align:right" | 24 | style="text-align:right" | 39 | 62.961161(78) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/63.pdf 1992] | 129(2)&nbsp;ms | β⁻ | ⁶³Mn | 1/2−# | | |-id=Chromium-64 | ⁶⁴Cr | style="text-align:right" | 24 | style="text-align:right" | 40 | 63.96389(32) | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/64.pdf 1992] | 43(1)&nbsp;ms | β⁻ | ⁶⁴Mn | 0+ | | |-id=Chromium-65 | ⁶⁵Cr | style="text-align:right" | 24 | style="text-align:right" | 41 | 64.96961(22)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/65.pdf 1997] | 27.5(21)&nbsp;ms | β⁻ | ⁶⁵Mn | 1/2−# | | |-id=Chromium-66 | ⁶⁶Cr | style="text-align:right" | 24 | style="text-align:right" | 42 | 65.97301(32)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/66.pdf 1997] | 23.8(18)&nbsp;ms | β⁻ | ⁶⁶Mn | 0+ | | |-id=Chromium-67 | ⁶⁷Cr | style="text-align:right" | 24 | style="text-align:right" | 43 | 66.97931(43)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/67.pdf 1997] | 11#&nbsp;ms<br>[>300&nbsp;ns] | | | 1/2−# | | |-id=Chromium-68 | ⁶⁸Cr | style="text-align:right" | 24 | style="text-align:right" | 44 | 67.98316(54)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/68.pdf 2009] | 10#&nbsp;ms<br>[>620&nbsp;ns] | | | 0+ | | |-id=Chromium-69 | ⁶⁹Cr | style="text-align:right" | 24 | style="text-align:right" | 45 | 68.98966(54)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/69.pdf 2013] | 6#&nbsp;ms<br>[>620&nbsp;ns] | | | 7/2+# | | |-id=Chromium-70 | ⁷⁰Cr | style="text-align:right" | 24 | style="text-align:right" | 46 | 69.99395(64)# | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/70.pdf 2013] | 6#&nbsp;ms<br>[>620&nbsp;ns] | | | 0+ | | |-id=Chromium-72 | ⁷²Cr<ref name="Shimizu2026">{{cite journal |last1=Shimizu |first1=Y |last2=Rykaczewski |first2=K P |last3=Fukuda |first3=N |last4=Brewer |first4=N T |last5=Dillmann |first5=I |last6=Grzywacz |first6=R K |last7=Nishimura |first7=S |last8=Rasco |first8=B C |last9=Tain |first9=J L |last10=Suzuki |first10=H |last11=Takeda |first11=H |last12=Ahn |first12=D S |last13=Sumikama |first13=T |last14=Inabe |first14=N |last15=Yoshida |first15=K |last16=Ueno |first16=H |last17=Michimasa |first17=S |last18=Algora |first18=A |last19=Allmond |first19=J M |last20=Agramunt |first20=J |last21=Baba |first21=H |last22=Bae |first22=S |last23=Bruno |first23=C G |last24=Caballero-Folch |first24=R |last25=Calvino |first25=F |last26=Coleman-Smith |first26=P J |last27=Cortes |first27=G |last28=Davinson |first28=T |last29=Domingo-Pardo |first29=C |last30=Estrade |first30=A |last31=Go |first31=S |last32=Griffin |first32=C J |last33=Ha |first33=J |last34=Hall |first34=O |last35=Harkness-Brennan |first35=L J |last36=Heideman |first36=J |last37=Isobe |first37=T |last38=Kahl |first38=D |last39=Karny |first39=M |last40=Khiem |first40=L H |last41=King |first41=T T |last42=Kiss |first42=G G |last43=Korgul |first43=A |last44=Kubono |first44=S |last45=Labiche |first45=M |last46=Lazarus |first46=I |last47=Liang |first47=J |last48=Liu |first48=J |last49=Lorusso |first49=G |last50=Madurga |first50=M |last51=Matsui |first51=K |last52=Miernik |first52=K |last53=Montes |first53=F |last54=Morales |first54=A I |last55=Morrall |first55=P |last56=Nepal |first56=N |last57=Page |first57=R D |last58=Phong |first58=V H |last59=Piersa-Siłkowska |first59=M |last60=Prydderch |first60=M |last61=Pucknell |first61=V F E |last62=Rajabali |first62=M M |last63=Rubio |first63=B |last64=Saito |first64=Y |last65=Sakurai |first65=H |last66=Simpson |first66=J |last67=Singh |first67=M |last68=Stracener |first68=D W |last69=Tarifeño-Saldivia |first69=A |last70=Thomas |first70=S L |last71=Tolosa-Delgado |first71=A |last72=Wolinska-Cichocka |first72=M |last73=Woods |first73=P J |last74=Xu |first74=X X |last75=Yokoyama |first75=R |title=Exploration of Neutron-Rich Isotopes around N = 50 via the In-Flight Fission of a 345 MeV/Nucleon 238U Beam |journal=Progress of Theoretical and Experimental Physics |date=6 March 2026 |volume=2026 |issue=3 |doi=10.1093/ptep/ptag036}}</ref> | style="text-align:right" | 24 | style="text-align:right" | 48 | | style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/24/72.pdf 2026] | | | | 0+ | | {{Isotopes table/footer}}

== Chromium-51 == Chromium-51 is a synthetic radioactive isotope of chromium having a half-life of 27.70 days and decaying by electron capture and emitting a 320-keV gamma ray; 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-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.<ref>{{Cite web |title=Chromium-51 |url=https://pubchem.ncbi.nlm.nih.gov/compound/Chromium-51#section=Structures}}</ref>

== See also == '''Daughter products other than chromium''' * Isotopes of manganese * Isotopes of vanadium * Isotopes of titanium * Isotopes of scandium

==References== {{Reflist}}

{{Navbox element isotopes}}

Category:Isotopes of chromium Category:Chromium Chromium