All atomic nuclei of the chemical element arsenic are summarized under arsenic isotopes; these consist of an atomic nucleus with 33 protons and, in the uncharged state, 33 electrons. The difference between the individual arsenic isotopes is due to the number of neutrons in the nucleus.
The arsenic is mononuclide element or pure element; it only occurs in nature in the form of a single nuclide: arsenic-75.
The standard atomic mass of arsenic is 74.921595(6) u.
In addition to the natural and only stable arsenic isotope, 29 other unstable nuclides are known and have been characterized accordingly.
Isotope Nuclide | E | N | Atomic Mass [Nuclear Mass] {Mass Excess} | Spin I (h/2π) | Parent |
---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 |
Arsenic-62 | 6233As | 29 | 61.97320(32) u [61.9550975 u] {-24.96404 MeV} | 1+ | |
Arsenic-63 | 6333As | 30 | 62.96404(21) u [62.9459375 u] {-33.49652 MeV} | 3/2- | |
Arsenic-64 | 6433As | 31 | 63.95756(22) u [63.9394575 u] {-39.53261 MeV} | 0+ | |
Arsenic-65 | 6533As | 32 | 64.94961(9) u [64.9315075 u] {-46.93798 MeV} | 3/2- | |
Arsenic-66 | 6633As | 33 | 65.944149(6) u [65.9260465 u] {-52.02487 MeV} | (0+) | |
Arsenic-66m1 | 66m133As | 33 | 65.944149(6) u [65.9260465 u] {-52.02487 MeV} | (5+) | |
Arsenic-66m2 | 66m233As | 33 | 65.944149(6) u [65.9260465 u] {-52.02487 MeV} | (9+) | |
Arsenic-67 | 6733As | 34 | 66.9392511(5) u [66.9211486 u] {-56.58724 MeV} | (5/2-) | 67Se |
Arsenic-68 | 6833As | 35 | 67.9367741(20) u [67.9186715 u] {-58.89464 MeV} | 3+ | 68Se |
Arsenic-68m | 68m33As | 35 | 67.936774(20) u [67.9186715 u] {-58.89464 MeV} | 1+ | |
Arsenic-69 | 6933As | 36 | 68.93225(3) u [68.9141475 u] {-63.10872 MeV} | 5/2- | 69Se |
Arsenic-70 | 7033As | 37 | 69.93093(5) u [69.9128275 u] {-64.33829 MeV} | 4+ | 70Se |
Arsenic-70m | 70m33As | 37 | 69.93093(5) u [69.9128275 u] {-64.33829 MeV} | 2+ | |
Arsenic-71 | 7133As | 38 | 70.927114(4) u [70.9090115 u] {-67.89287 MeV} | 5/2- | 71Se |
Arsenic-72 | 7233As | 39 | 71.926752(4) u [71.9086495 u] {-68.23007 MeV} | 2- | 72Se |
Arsenic-73 | 7333As | 40 | 72.923829(4) u [72.9057265 u] {-70.95283 MeV} | 3/2- | 73Se |
Arsenic-73m | 73m33As | 40 | 72.923829(4) u [72.9057265 u] {-70.95283 MeV} | 9/2+ | |
Arsenic-74 | 7433As | 41 | 73.9239286(18) u [73.9058261 u] {-70.86005 MeV} | 2- | |
Arsenic-75 | 7533As | 42 | 74.921595(6) u [74.9034925 u] {-73.03379 MeV} | 3/2- | 75Se 75Ge |
Arsenic-75m | 75m33As | 42 | 74.921595(6) u [74.9034925 u] {-73.03379 MeV} | 9/2+ | |
Arsenic-76 | 7633As | 43 | 75.922392(1) u [75.9042895 u] {-72.29139 MeV} | 2- | |
Arsenic-76m | 76m33As | 43 | 75.922392(1) u [75.9042895 u] {-72.29139 MeV} | (1)+ | |
Arsenic-77 | 7733As | 44 | 76.9206476(18) u [76.9025451 u] {-73.91628 MeV} | 3/2- | 77Ge |
Arsenic-77m | 77m33As | 44 | 76.9206476(18) u [76.9025451 u] {-73.91628 MeV} | 9/2+ | |
Arsenic-78 | 7833As | 45 | 77.921828(10) u [77.9037255 u] {-72.81675 MeV} | 2- | 78Ge |
Arsenic-79 | 7933As | 46 | 78.920948(6) u [78.9028455 u] {-73.63646 MeV} | 3/2- | 79Ge |
Arsenic-79m | 79m33As | 46 | 78.920948(6) u [78.9028455 u] {-73.63646 MeV} | (9/2)+ | |
Arsenic-80 | 8033As | 47 | 79.922475(4) u [79.9043725 u] {-72.21407 MeV} | 1+ | 80Ge |
Arsenic-81 | 8133As | 48 | 80.9221323(28) u [80.9040298 u] {-72.5333 MeV} | 3/2- | 81Ge |
Arsenic-82 | 8233As | 49 | 81.924739(4) u [81.9066365 u] {-70.10517 MeV} | (2-) | 82Ge |
Arsenic-82m | 82m33As | 49 | 81.924739(4) u [81.9066365 u] {-70.10517 MeV} | (5-) | |
Arsenic-83 | 8333As | 50 | 82.925207(3) u [82.9071045 u] {-69.66923 MeV} | (5/2-) | 83Ge |
Arsenic-84 | 8433As | 51 | 83.929303(3) u [83.9112005 u] {-65.85383 MeV} | (3-) | 84Ge |
Arsenic-85 | 8533As | 52 | 84.932164(3) u [84.9140615 u] {-63.18883 MeV} | (3/2-) | 85Ge |
Arsenic-86 | 8633As | 53 | 85.936702(4) u [85.9185995 u] {-58.96171 MeV} | ||
Arsenic-87 | 8733As | 54 | 86.940292(3) u [86.9221895 u] {-55.61764 MeV} | (3/2-) | |
Arsenic-88 | 8833As | 55 | 87.94555(21) u [87.9274475 u] {-50.71985 MeV} | ||
Arsenic-89 | 8933As | 56 | 88.94976(32) u [88.9316575 u] {-46.79826 MeV} | ||
Arsenic-90 | 9033As | 57 | 89.95563(43) u [89.9375275 u] {-41.33039 MeV} | ||
Arsenic-91 | 9133As | 58 | 90.96039(43) u [90.9422875 u] {-36.89648 MeV} | ||
Arsenic-92 | 9233As | 59 | 91.96674(54) u [91.9486375 u] {-30.98149 MeV} |
Isotope | Radioactive Decay | Extern | |||
---|---|---|---|---|---|
Half-life | Decay Mode | Probability | Energy | ||
7 | 8 | 9 | 10 | 11 | 12 |
As-62 | p → 61Ge | AL | |||
As-63 | 43 ns | p → 62Ge | ? | AL | |
As-64 | 18 ms | EC/β+ → 64Ge | 100 % | 14.78(20) MeV | AL |
As-65 | 128(16) ms | EC/β+ → 65Ge | 100 % | 9.54(8) MeV | AL |
As-66 | 95.77(23) ms | EC/β+ → 66Ge | 100 % | 9.582(6) MeV | AL |
As-66m1 | 1.1(1) μs | ||||
As-66m2 | 8.2 | ||||
As-67 | 42.5(12) s | EC/β+ → 67Ge | 100 % | 6.071(5) MeV | AL |
As-68 | 151.6(8) s | EC/β+ → 68Ge | 100 % | 8.0843(26) MeV | AL |
As-68m | 107(+23-16) ns | ||||
As-69 | 15.2(2) min | EC/β+ → 69Ge | 100 % | 3.988(32) MeV | AL |
As-70 | 52.6(3) min | EC/β+ → 70Ge | 100 % | 6.22(5) MeV | AL |
As-70m | 96(3) μs | ||||
As-71 | 65.30(7) h | EC/β+ → 71Ge | 100 % | 2.013(4) MeV | AL |
As-72 | 26.0(1) h | EC/β+ → 72Ge | 100 % | 4.356(4) MeV | AL |
As-73 | 80.30(6) d | EC → 73Ge | 100 % | 0.345(4) MeV | AL |
As-73m | 5.7(2) μs | Iso → 73As | |||
As-74 | 17.77(2) d | EC/β+ → 74Ge β- → 74Se | 66(2) % 34(2) % | 2.5624(17) MeV 1.3531(17) MeV | AL |
As-75 | stable | AL | |||
As-75m | 17.62(23) ms | Iso → 75As | 100 % | AL | |
As-76 | 26.24(9) h | β- → 76Se | 100 % | 2.9606(9) MeV | AL |
As-76m | 1.84(6) μs | ||||
As-77 | 38.79(5) h | β- → 77Se | 100 % | 0.6832(17) MeV | AL |
As-77m | 114.0(25) μs | Iso → 77As | 100 % | AL | |
As-78 | 90.7(2) min | β- → 78Se | 100 % | 4.209(10) MeV | AL |
As-79 | 9.01(15) min | β- → 79Se | 100 % | 2.281(5) MeV | AL |
As-79m | 1.21(1) μs | Iso → 79As | 100 % | AL | |
As-80 | 15.2(2) s | β- → 80Se | 100 % | 5.545(3) MeV | AL |
As-81 | 33.3(8) s | β- → 81Se | 100 % | 3.8557(28) MeV | AL |
As-82 | 19.1(5) s | β- → 82Se | 100 % | 7.488(4) MeV | AL |
As-82m | 13.6(4) s | β- → 82Se | 100 % | AL | |
As-83 | 13.4(3) s | β- → 83Se | 100 % | 5.671(4) MeV | AL |
As-84 | 4.2(5) s | β- → 84Se β-, n → 83Se | 99.82 % 0.18 % | 10.094(4) MeV 1.416(4) MeV | AL |
As-85 | 2.021(12) s | β- → 85Se β-, n → 84Se | 37.1 % 62.9(20) % | 9.224(4) MeV 4.687(4) MeV | AL |
As-86 | 945(8) ms | β- → 86Se β-, n → 85Se β-, 2n → 84Se | 35.5(6) % ? | 11.541(4) MeV 5.380(4) MeV | AL |
As-87 | 484(40) ms | β- → 87Se β-, n → 86Se | 84.6 % 15.4(22) % | 10.808(4) MeV 6.814(4) MeV | AL |
As-88 | 0.20(+20-9) s | β- → 88Se β-, n → 87Se | ? | 13.16(20) MeV 7.63(20) MeV | AL |
As-89 | 300 ns | β- → 89Se β-, n → 88Se β-, 2n → 87Se | ? ? ? | 12.19(30) MeV 9.01(30) MeV | AL |
As-90 | 300 ns | β- → 90Se β-, n → 89Se β-, 2n → 88Se | 14.47(52) MeV 9.59(40) MeV | AL | |
As-91 | β- → 91Se β-, n → 90Se | 16.68(59) MeV 10.83(52) MeV | AL | ||
As-92 | β- → 92Se | ? | 1.574(64) 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 Arsenic 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 Arsenic 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) |
---|---|---|---|---|
75As 100 % 3/2- | +1,4383(3) | 4,5961 {+ 0,311(2)} | 7,3150 | 0,02536 0,8590 |
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 Arsenic radionuclides:
Nuclide | Limit Value | HASS limit | SC | Daughter Nuclides | Half-life | |
---|---|---|---|---|---|---|
As-69 | 105 Bq | 10 Bq/g | 15.2 min | |||
As-70 | 105 Bq | 10 Bq/g | 52.6 min | |||
As-71 | 106 Bq | 10 Bq/g | 65.3 h | |||
As-72 | 105 Bq | 10 Bq/g | 0,04 TBq | 26.0 h | ||
As-73+ | 107 Bq | 1000 Bq/g | 40 TBq | 100 Bq cm-2 | 80.3 d | |
As-74 | 106 Bq | 10 Bq/g | 0,09 TBq | 1 Bq cm-2 | 17.8 d | |
As-76 | 105 Bq | 10 Bq/g | 0,2 TBq | 10 Bq cm-2 | 26.4 h | |
As-77 | 106 Bq | 1000 Bq/g | 8 TBq | 100 Bq cm-2 | 38.8 h | |
As-78 | 105 Bq | 10 Bq/g | 1.5 h |
(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)
Properties of the Arsenic 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.
Arsenic: NMR properties - 75As-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] - Marc Jennewein:
Production, radiochemical separation and chemical coupling of radioactive arsenic isotopes to synthesize radiopharmaceuticals for molecular imaging.
In: Dissertation Chemie, Universität Mainz, (2005).
[10] - Markus Jahn:
Nicht geträgerte Radioarsenisotope: ihre Herstellung, Abtrennung und Markierung von Proteinen.
In: Dissertation Chemie, Universität Mainz, (2009).
[11] - A. Shore, A. Fritsch, M. Heim, A. Schuh, M. Thoennessen:
Discovery of the arsenic isotopes.
In: Atomic Data and Nuclear Data Tables, (2010), DOI 10.1016/j.adt.2009.11.001.
Last update: 2022-12-12
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