Naturally occurring

chromium Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. Chromium metal is valued for its high corrosion resistance and hardne ...

(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 with 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, the least stable being ⁶⁶Cr with a half-life of 10 milliseconds. This element also has 2 meta states, ^45mCr, the more stable one, and ^59mCr, the least stable isotope or isomer. ⁵³Cr is the radiogenic decay product of ⁵³ Mn. 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 ²⁶ Al and ¹⁰⁷ Pd 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. The isotopes of chromium range from ⁴²Cr to ⁶⁷Cr. The primary

decay mode Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consid ...

before the most abundant stable isotope, ⁵²Cr, is electron capture and the primary mode after is beta decay.

List of isotopes

, - , rowspan=2, ⁴²Cr , rowspan=2 style="text-align:right" , 24 , rowspan=2 style="text-align:right" , 18 , rowspan=2, 42.00643(32)# , rowspan=2, 14(3) ms
3(+4-2) ms, β⁺ (>99.9%) , ⁴²V , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , 2p (<.1%) , ⁴⁰Ti , - , rowspan=4, ⁴³Cr , rowspan=4 style="text-align:right" , 24 , rowspan=4 style="text-align:right" , 19 , rowspan=4, 42.99771(24)# , rowspan=4, 21.6(7) ms , β⁺ (71%) , ⁴³V , rowspan=4, (3/2+) , rowspan=4, , rowspan=4, , - , β⁺, p (23%) , ⁴²Ti , - , β⁺, 2p (6%) , ⁴¹Sc , - , β⁺, α (<.1%) , ³⁹Sc , - , rowspan=2, ⁴⁴Cr , rowspan=2 style="text-align:right" , 24 , rowspan=2 style="text-align:right" , 20 , rowspan=2, 43.98555(5)# , rowspan=2, 54(4) ms
3(+4-3) ms, β⁺ (93%) , ⁴⁴V , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺, p (7%) , ⁴³Ti , - , rowspan=2, ⁴⁵Cr , rowspan=2 style="text-align:right" , 24 , rowspan=2 style="text-align:right" , 21 , rowspan=2, 44.97964(54) , rowspan=2, 50(6) ms , β⁺ (73%) , ⁴⁵V , rowspan=2, 7/2−# , rowspan=2, , rowspan=2, , - , β⁺, p (27%) , ⁴⁴Ti , - , rowspan=2 style="text-indent:1em" , ^45mCr , rowspan=2 colspan="3" style="text-indent:2em" , 50(100)# keV , rowspan=2, 1# ms , IT , ⁴⁵Cr , rowspan=2, 3/2+# , rowspan=2, , rowspan=2, , - , β⁺ , ⁴⁵V , - , ⁴⁶Cr , style="text-align:right" , 24 , style="text-align:right" , 22 , 45.968359(21) , 0.26(6) s , β⁺ , ⁴⁶V , 0+ , , , - , ⁴⁷Cr , style="text-align:right" , 24 , style="text-align:right" , 23 , 46.962900(15) , 500(15) ms , β⁺ , ⁴⁷V , 3/2− , , , - , ⁴⁸Cr , style="text-align:right" , 24 , style="text-align:right" , 24 , 47.954032(8) , 21.56(3) h , β⁺ , ⁴⁸V , 0+ , , , - , ⁴⁹Cr , style="text-align:right" , 24 , style="text-align:right" , 25 , 48.9513357(26) , 42.3(1) min , β⁺ , ⁴⁹V , 5/2− , , , - , ⁵⁰Cr , style="text-align:right" , 24 , style="text-align:right" , 26 , 49.9460442(11) , colspan=3 align=center, Observationally StableSuspected of decaying by double electron capture to ⁵⁰Ti with a half-life of no less than 1.3 a , 0+ , 0.04345(13) , 0.04294–0.04345 , - , ⁵¹Cr , style="text-align:right" , 24 , style="text-align:right" , 27 , 50.9447674(11) , 27.7025(24) d , EC , ⁵¹V , 7/2− , , , - , ⁵²Cr , style="text-align:right" , 24 , style="text-align:right" , 28 , 51.9405075(8) , colspan=3 align=center, Stable , 0+ , 0.83789(18) , 0.83762–0.83790 , - , ⁵³Cr , style="text-align:right" , 24 , style="text-align:right" , 29 , 52.9406494(8) , colspan=3 align=center, Stable , 3/2− , 0.09501(17) , 0.09501–0.09553 , - , ⁵⁴Cr , style="text-align:right" , 24 , style="text-align:right" , 30 , 53.9388804(8) , colspan=3 align=center, Stable , 0+ , 0.02365(7) , 0.02365–0.02391 , - , ⁵⁵Cr , style="text-align:right" , 24 , style="text-align:right" , 31 , 54.9408397(8) , 3.497(3) min , β⁻ , ⁵⁵Mn , 3/2− , , , - , ⁵⁶Cr , style="text-align:right" , 24 , style="text-align:right" , 32 , 55.9406531(20) , 5.94(10) min , β⁻ , ⁵⁶Mn , 0+ , , , - , ⁵⁷Cr , style="text-align:right" , 24 , style="text-align:right" , 33 , 56.943613(2) , 21.1(10) s , β⁻ , ⁵⁷Mn , (3/2−) , , , - , ⁵⁸Cr , style="text-align:right" , 24 , style="text-align:right" , 34 , 57.94435(22) , 7.0(3) s , β⁻ , ⁵⁸Mn , 0+ , , , - , ⁵⁹Cr , style="text-align:right" , 24 , style="text-align:right" , 35 , 58.94859(26) , 460(50) ms , β⁻ , ⁵⁹Mn , 5/2−# , , , - , style="text-indent:1em" , ^59mCr , colspan="3" style="text-indent:2em" , 503.0(17) keV , 96(20) µs , , , (9/2+) , , , - , ⁶⁰Cr , style="text-align:right" , 24 , style="text-align:right" , 36 , 59.95008(23) , 560(60) ms , β⁻ , ⁶⁰Mn , 0+ , , , - , rowspan=2, ⁶¹Cr , rowspan=2 style="text-align:right" , 24 , rowspan=2 style="text-align:right" , 37 , rowspan=2, 60.95472(27) , rowspan=2, 261(15) ms , β⁻ (>99.9%) , ⁶¹Mn , rowspan=2, 5/2−# , rowspan=2, , rowspan=2, , - , β⁻, n (<.1%) , ⁶⁰Mn , - , rowspan=2, ⁶²Cr , rowspan=2 style="text-align:right" , 24 , rowspan=2 style="text-align:right" , 38 , rowspan=2, 61.95661(36) , rowspan=2, 199(9) ms , β⁻ (>99.9%) , ⁶²Mn , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁻, n , ⁶¹Mn , - , rowspan=2, ⁶³Cr , rowspan=2 style="text-align:right" , 24 , rowspan=2 style="text-align:right" , 39 , rowspan=2, 62.96186(32)# , rowspan=2, 129(2) ms , β⁻ , ⁶³Mn , rowspan=2, (1/2−)# , rowspan=2, , rowspan=2, , - , β⁻, n , ⁶²Mn , - , ⁶⁴Cr , style="text-align:right" , 24 , style="text-align:right" , 40 , 63.96441(43)# , 43(1) ms , β⁻ , ⁶⁴Mn , 0+ , , , - , ⁶⁵Cr , style="text-align:right" , 24 , style="text-align:right" , 41 , 64.97016(54)# , 27(3) ms , β⁻ , ⁶⁵Mn , (1/2−)# , , , - , ⁶⁶Cr , style="text-align:right" , 24 , style="text-align:right" , 42 , 65.97338(64)# , 10(6) ms , β⁻ , ⁶⁶Mn , 0+ , , , - , ⁶⁷Cr , style="text-align:right" , 24 , style="text-align:right" , 43 , 66.97955(75)# , 10# ms
300 ns, β⁻ , ⁶⁷Mn , 1/2−# , ,

Chromium-51

Chromium-51 is a manmade isotope of chromium used in medicine as a radioisotopic tracer.

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** **

External links

Chromium isotopes data from ''The Berkeley Laboratory Isotopes Project's''
{{Navbox element isotopes Chromium

Chromium Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. Chromium metal is valued for its high corrosion resistance and hardne ...