All atomic nuclei of the chemical element chromium are summarized under chromium isotopes; these all consist of an atomic nucleus with 24 protons and, in the uncharged state, 24 electrons. The difference between each chromium isotope is based on the number of neutrons in the nucleus.
In nature, 4 isotopes of chromium occur in different forms:
| Atomic Mass ma | Quantity | Half-life | Spin | |
| Chromium Isotopic mixture | 51,9961 u | 100 % | ||
| Isotope 50Cr | 49,9460414(5) u | 4,345(13) % | 1.3 × 1018 a | 0+ |
| Isotope 52Cr | 51,940506(4) u | 83,789(18) % | stable | 0+ |
| Isotope 53Cr | 52,940648(4) u | 9,501(17) % | stable | 3/2- |
| Isotope 54Cr | 53,938879(4) u | 2,365(7) % | stable | 0+ |
| Isotope Nuclide | E | N | Atomic Mass [Nuclear Mass] {Mass Excess} | Spin I (h/2π) | Parent |
|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 |
| Chromium-41 | 4124Cr | 17 | 41.02 u [41.0068344 u] {18.62988 MeV} | 42Mn | |
| Chromium-42 | 4224Cr | 18 | 42.00722(43) u [41.9940544 u] {6.72539 MeV} | 0+ | 43Mn |
| Chromium-43 | 4324Cr | 19 | 42.99788(43) u [42.9847144 u] {-1.97477 MeV} | (3/2+) | 44Mn |
| Chromium-44 | 4424Cr | 20 | 43.98566(32) u [43.9724944 u] {-13.35762 MeV} | 0+ | 45Mn |
| Chromium-45 | 4524Cr | 21 | 44.97905(4) u [44.9658844 u] {-19.5148 MeV} | (7/2-) | |
| Chromium-45m | 45m24Cr | 21 | 44.97905(4) u [44.9658844 u] {-19.5148 MeV} | 3/2+~ | |
| Chromium-46 | 4624Cr | 22 | 45.968359(21) u [45.9551934 u] {-29.4734 MeV} | 0+ | 46Mn |
| Chromium-47 | 4724Cr | 23 | 46.962896(6) u [46.9497304 u] {-34.56215 MeV} | 3/2- | 47Mn |
| Chromium-48 | 4824Cr | 24 | 47.954029(8) u [47.9408634 u] {-42.82171 MeV} | 0+ | 48Mn |
| Chromium-49 | 4924Cr | 25 | 48.9513330(24) u [48.9381674 u] {-45.33302 MeV} | 5/2- | 49Mn |
| Chromium-50 | 5024Cr | 26 | 49.9460414(5) u [49.9328758 u] {-50.26211 MeV} | 0+ | 50Mn 50V |
| Chromium-51 | 5124Cr | 27 | 50.94476539(18) u [50.9315998 u] {-51.45071 MeV} | 7/2- | 51Mn |
| Chromium-52 | 5224Cr | 28 | 51.940506(4) u [51.9273404 u] {-55.4183 MeV} | 0+ | 52Mn 52V |
| Chromium-53 | 5324Cr | 29 | 52.940648(4) u [52.9274824 u] {-55.28603 MeV} | 3/2- | 53Mn 53V |
| Chromium-54 | 5424Cr | 30 | 53.938879(4) u [53.9257134 u] {-56.93384 MeV} | 0+ | 54Mn 54V |
| Chromium-55 | 5524Cr | 31 | 54.9408373(4) u [54.9276717 u] {-55.1097 MeV} | 3/2- | 55V |
| Chromium-56 | 5624Cr | 32 | 55.9406491(6) u [55.9274835 u] {-55.28501 MeV} | 0+ | 56V |
| Chromium-57 | 5724Cr | 33 | 56.9436124(11) u [56.9304468 u] {-52.52471 MeV} | (3/2)- | 57V |
| Chromium-58 | 5824Cr | 34 | 57.9441845(16) u [57.9310189 u] {-51.9918 MeV} | 0+ | 58V |
| Chromium-59 | 5924Cr | 35 | 58.94838(23) u [58.9352144 u] {-48.08372 MeV} | (1/2-) | 59V |
| Chromium-59m | 59m24Cr | 35 | 58.94838(23) u [58.9352144 u] {-48.08372 MeV} | (9/2+) | |
| Chromium-60 | 6024Cr | 36 | 59.94990(21) u [59.9367344 u] {-46.66785 MeV} | 0+ | 60V |
| Chromium-61 | 6124Cr | 37 | 60.95440(11) u [60.9412344 u] {-42.47613 MeV} | (5/2-) | 61V |
| Chromium-62 | 6224Cr | 38 | 61.95610(16) u [61.9429344 u] {-40.89259 MeV} | 0+ | 62V |
| Chromium-63 | 6324Cr | 39 | 62.96134(38) u [62.9481744 u] {-36.01156 MeV} | 1/2- | 63V |
| Chromium-64 | 6424Cr | 40 | 63.96406(47) u [63.9508944 u] {-33.47789 MeV} | 0+ | 64V |
| Chromium-65 | 6524Cr | 41 | 64.96970(32) u [64.9565344 u] {-28.22427 MeV} | (1/2-) | 65V |
| Chromium-66 | 6624Cr | 42 | 65.97346(43) u [65.9602944 u] {-24.72185 MeV} | 0+ | |
| Chromium-67 | 6724Cr | 43 | 66.97955(75) u [66.9663844 u] {-19.04905 MeV} | 1/2-~ | |
| Chromium-68 | 6824Cr | 44 | 67.98411(54) u [67.9709444 u] {-14.80144 MeV} | 0+ |
| Isotope | Radioactive Decay | Extern | |||
|---|---|---|---|---|---|
| Half-life | Decay Mode | Probability | Energy | ||
| 7 | 8 | 9 | 10 | 11 | 12 |
| Cr-41 | p → 40V | ||||
| Cr-42 | 13.3(10) ms | β+ → 42V EC p → 41Ti | 94.4(50) % | 14.35(45) MeV | AL |
| Cr-43 | 21.2(7) ms | EC β+ → 43V EC, p → 42Ti EC, 2p → 41Sc EC, 3p → 40Ca | 79.3(30) % 11.6(10) % 0.13 % | 15.95(40) MeV | AL |
| Cr-44 | 42.8(6) ms | EC β+ → 44V EC, p → 43Ti | 93 % 7(3) % | 10.76(35) MeV | AL |
| Cr-45 | 60.9(4) ms | β+ → 45V β+, p → 44Ti | 65.6 % 34.4 % | 12.47(49) MeV | AL |
| Cr-45m | 0.001 s~ | AL | |||
| Cr-46 | 0.26(6) s | EC β+ → 46V | 100 % | 7.604(11) MeV | AL |
| Cr-47 | 500(15) ms | EC β+ → 47V | 100 % | 7.444(6) MeV | AL |
| Cr-48 | 21.56(3) h | EC/β+ → 48V | 100 % | 1.656(7) MeV | AL |
| Cr-49 | 42.3(1) min | β+ → 49V | 100 % | 2.6289(24) MeV | AL |
| Cr-50 | 1.3 × 1018 a | 2 EC ? | AL | ||
| Cr-51 | 27.704(4) d | EC → 51V | 100 % | 0.75239(19) MeV | AL |
| Cr-52 | stable | AL | |||
| Cr-53 | stable | AL | |||
| Cr-54 | stable | AL | |||
| Cr-55 | 3.497(3) min | β- → 55Mn | 100 % | 2.6027(4) MeV | AL |
| Cr-56 | 5.94(10) min | β- → 56Mn | 100 % | 1.6265(6) MeV | AL |
| Cr-57 | 21.1(10) s | β- → 57Mn | 100 % | 4.9615(18) MeV | AL |
| Cr-58 | 7.0(3) s | β- → 58Mn | 100 % | 3.836(4) MeV | AL |
| Cr-59 | 0.74(28) s | β- → 59Mn | 100 % | 7.44(22) MeV | AL |
| Cr-59m | 96(20) μs | Iso → 59Cr | 100 % | AL | |
| Cr-60 | 0.49(1) s | β- → 60Mn β-, n → 59Mn | ? | 6.30(19) MeV 0.78(19) MeV | AL |
| Cr-61 | 237(11) ms | β- → 61Mn β-, n → 60Mn | 100 % ? | 9.27(10) MeV 2.42(19) MeV | AL |
| Cr-62 | 206(12) ms | β- → 62Mn β- , n → 61Mn | 100 % ? | 7.63(15) MeV 2.78(15) MeV | AL |
| Cr-63 | 129(2) ms | β- → 63Mn β- , n → 62Mn | 100 % ? | 10.88(36) MeV 4.45(36) MeV | AL |
| Cr-64 | 43(1) ms | β- → 64Mn β-, n → → 63Mn | 100 % ? | 9.51(44) MeV 5.34(44) MeV | AL |
| Cr-65 | 27(3) ms | β- → 65Mn | 100 % | 12.75(39) MeV | AL |
| Cr-66 | 24(2) ms | β- → 66Mn | 100 % | 12.03(40) MeV | AL |
| Cr-67 | 300 ns | β- → 67Mn | AL | ||
| Cr-68 | 360 ns | β- → 68Mn β-, n → 67Mn | 100 % ? | 13.58(64) MeV 10.59(58) MeV | AL |
Notes (related to the columns):
1 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and Atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - relative atomic mass of the Chromium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
5 - nuclear spin I, unit: h/2π.
6 - source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.
7 - isotope notation in short form.
8 - decay: half-live of the Chromium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - other information and notes: AL = Adopted Levels (link to external data [1]).
Miscellaneous:
()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
- unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.
| Nuclide quantity 1) spin | Nuclear magnetic moment μ/μN | Gyromagnetic ratio {Quadrupole moment} | Resonant frequency v0 bei 1 T | Relative sensitivity H0 = const. v0 = const. 3) |
|---|---|---|---|---|
| 53Cr 9,501(17) % 3/2- | -0,47431(7) | - 1,512 {- 0,15(5)} | 2,4115 | 0,00091 0,2832 |
1) Quantity Percentage of natural occurrence.
2) Gyromagnetic ratio: 107 rad T-1 s-1
Quadrupole moment: Q [barn] = [100 fm2]
3) Related to 1H = 1,000.
According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Chromium radionuclides:
| Nuclide | Limit Value | HASS limit | SC | Daughter Nuclides | Half-life | |
|---|---|---|---|---|---|---|
| Cr-48 | 106 Bq | 100 Bq/g | 21.6 h | |||
| Cr-49 | 106 Bq | 10 Bq/g | 41.9 min | |||
| Cr-51 | 107 Bq | 100 Bq/g | 2 TBq | 100 Bq cm-2 | 27.7 d | |
(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)
Properties of the Chromium nucleides
[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.
[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.
[3] - Live Chart of Nuclides. Nuclear structure and decay data.
Chromium: NMR properties - 53Cr-NMR
[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.
[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.
[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.
[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).
More sources:
[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.
[9] - K. Garofali, R. Robinson, M. Thoennessen:
Discovery of chromium, manganese, nickel, and copper isotopes.
In: Atomic Data and Nuclear Data Tables, (2012), DOI 10.1016/j.adt.2011.11.002.
[10] - Martin Schiller, Elishevah Van Kooten, Jesper C. Holst, Mia B. Olsena, Martin Bizzarro:
Precise measurement of chromium isotopes by MC-ICPMS.
In: Journal of Analytical Atomic Spectrometry, (2014), DOI 10.1039/C4JA00018H.
Last update: 2022-12-12
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