Naturally occurring chromium (₂₄Cr) is composed of four stable

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

s; 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 Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

of (more than) 1.8×10¹⁷ years. Twenty-two

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

s, 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 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 consi ...

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 state A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy higher energy levels than in the ground state of the same nucleus. "Metastable" describes nuclei whose excited states have ...

s, ^45mCr, the more stable one, and ^59mCr, the least stable isotope or isomer. ⁵³Cr is the

radiogenic A radiogenic nuclide is a nuclide that is produced by a process of radioactive decay. It may itself be radioactive (a radionuclide) or stable (a stable nuclide). Radiogenic nuclides (more commonly referred to as radiogenic isotopes) form some ...

decay product of ⁵³ Mn. Chromium isotopic contents are typically combined with

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

isotopic contents and have found application in

isotope geology Isotope geochemistry is an aspect of geology based upon the study of natural variations in the relative abundances of isotopes of various elements. Variations in isotopic abundance are measured by isotope ratio mass spectrometry, and can reveal ...

. Mn-Cr isotope ratios reinforce the evidence from ²⁶ Al and ¹⁰⁷ Pd for the early history of the

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

. 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 Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). and may refer to: * Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amou ...

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 before the most abundant stable isotope, ⁵²Cr, is

electron capture Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Thi ...

and the primary mode after is

beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...

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 Stable Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes. Th ...

Suspected 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