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Standard atomic weight Ar°(As) | ||||||||||||||||||||||||||||||||||
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Arsenic (33As) has 33 known isotopes and at least 10 isomers. Only one of these isotopes, 75As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is 73As with a half-life of 80 days. Arsenic has been proposed as a "salting" material for nuclear weapons (cobalt is another, better-known salting material). A jacket of 75As, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope 76As with a half-life of 1.0778 days and produce approximately 1.13 MeV gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several hours. Such a weapon is not known to have ever been built, tested, or used.
Transmutation of arsenic to much less toxic selenium could prevent cycling of arsenic, from groundwater to waterways to oceans and back via Sargassum seaweeds. Bioremediation can provide a large supply of arsenic and rid aquifers of persistent poisoning issues.
List of isotopes
Nuclide [n 1] |
Z | N | Isotopic mass (Da) [n 2][n 3] |
Half-life |
Decay mode [n 4] |
Daughter isotope [n 5][n 6] |
Spin and parity [n 7][n 8] |
Natural abundance (mole fraction) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Excitation energy[n 8] | Normal proportion | Range of variation | |||||||||||||||||
60As | 33 | 27 | 59.99313(64)# | p | 59Ge | 5+# | |||||||||||||
61As | 33 | 28 | 60.98062(64)# | p | 60Ge | 3/2−# | |||||||||||||
62As | 33 | 29 | 61.97320(32)# | p | 61Ge | 1+# | |||||||||||||
63As | 33 | 30 | 62.96369(54)# | p | 62Ge | (3/2−)# | |||||||||||||
64As | 33 | 31 | 63.95757(38)# | 40(30) ms [18(+43-7) ms] |
β+ | 64Ge | 0+# | ||||||||||||
65As | 33 | 32 | 64.94956(32)# | 170(30) ms | β+ | 65Ge | 3/2−# | ||||||||||||
66As | 33 | 33 | 65.94471(73) | 95.77(23) ms | β+ | 66Ge | (0+) | ||||||||||||
66m1As | 1356.70(17) keV | 1.1(1) µs | (5+) | ||||||||||||||||
66m2As | 3023.9(3) keV | 8.2(5) µs | (9+) | ||||||||||||||||
67As | 33 | 34 | 66.93919(11) | 42.5(12) s | β+ | 67Ge | (5/2−) | ||||||||||||
68As | 33 | 35 | 67.93677(5) | 151.6(8) s | β+ | 68Ge | 3+ | ||||||||||||
68mAs | 425.21(16) keV | 111(20) ns [?107(+23-16) ns] |
1+ | ||||||||||||||||
69As | 33 | 36 | 68.93227(3) | 15.2(2) min | β+ | 69Ge | 5/2− | ||||||||||||
70As | 33 | 37 | 69.93092(5) | 52.6(3) min | β+ | 70Ge | 4(+#) | ||||||||||||
70mAs | 32.008(23) keV | 96(3) µs | 2(+) | ||||||||||||||||
71As | 33 | 38 | 70.927112(5) | 65.28(15) h | β+ | 71Ge | 5/2− | ||||||||||||
72As | 33 | 39 | 71.926752(5) | 26.0(1) h | β+ | 72Ge | 2− | ||||||||||||
73As | 33 | 40 | 72.923825(4) | 80.30(6) d | EC | 73Ge | 3/2− | ||||||||||||
74As | 33 | 41 | 73.9239287(25) | 17.77(2) d | β+ (66%) | 74Ge | 2− | ||||||||||||
β− (34%) | 74Se | ||||||||||||||||||
75As | 33 | 42 | 74.9215965(20) | Stable | 3/2− | 1.0000 | |||||||||||||
75mAs | 303.9241(7) keV | 17.62(23) ms | 9/2+ | ||||||||||||||||
76As | 33 | 43 | 75.922394(2) | 1.0942(7) d | β− (99.98%) | 76Se | 2− | ||||||||||||
EC (.02%) | 76Ge | ||||||||||||||||||
76mAs | 44.425(1) keV | 1.84(6) µs | (1)+ | ||||||||||||||||
77As | 33 | 44 | 76.9206473(25) | 38.83(5) h | β− | 77mSe | 3/2− | ||||||||||||
77mAs | 475.443(16) keV | 114.0(25) µs | 9/2+ | ||||||||||||||||
78As | 33 | 45 | 77.921827(11) | 90.7(2) min | β− | 78Se | 2− | ||||||||||||
79As | 33 | 46 | 78.920948(6) | 9.01(15) min | β− | 79mSe | 3/2− | ||||||||||||
79mAs | 772.81(6) keV | 1.21(1) µs | (9/2)+ | ||||||||||||||||
80As | 33 | 47 | 79.922534(25) | 15.2(2) s | β− | 80Se | 1+ | ||||||||||||
81As | 33 | 48 | 80.922132(6) | 33.3(8) s | β− | 81mSe | 3/2− | ||||||||||||
82As | 33 | 49 | 81.92450(21) | 19.1(5) s | β− | 82Se | (1+) | ||||||||||||
82mAs | 250(200) keV | 13.6(4) s | β− | 82Se | (5-) | ||||||||||||||
83As | 33 | 50 | 82.92498(24) | 13.4(3) s | β− | 83mSe | 3/2−# | ||||||||||||
84As | 33 | 51 | 83.92906(32)# | 4.02(3) s | β− (99.721%) | 84Se | (3)(+#) | ||||||||||||
β−, n (.279%) | 83Se | ||||||||||||||||||
84mAs | 0(100)# keV | 650(150) ms | |||||||||||||||||
85As | 33 | 52 | 84.93202(21)# | 2.021(10) s | β−, n (59.4%) | 84Se | (3/2−)# | ||||||||||||
β− (40.6%) | 85Se | ||||||||||||||||||
86As | 33 | 53 | 85.93650(32)# | 0.945(8) s | β− (67%) | 86Se | |||||||||||||
β−, n (33%) | 85Se | ||||||||||||||||||
87As | 33 | 54 | 86.93990(32)# | 0.56(8) s | β− (84.6%) | 87Se | 3/2−# | ||||||||||||
β−, n (15.4%) | 86Se | ||||||||||||||||||
88As | 33 | 55 | 87.94494(54)# | 300# ms [>300 ns] |
β− | 88Se | |||||||||||||
β−, n | 87Se | ||||||||||||||||||
89As | 33 | 56 | 88.94939(54)# | 200# ms [>300 ns] |
β− | 89Se | 3/2−# | ||||||||||||
90As | 33 | 57 | 89.95550(86)# | 80# ms [>300 ns] |
|||||||||||||||
91As | 33 | 58 | 90.96043(97)# | 50# ms [>300 ns] |
3/2−# | ||||||||||||||
92As | 33 | 59 | 91.96680(97)# | 30# ms [>300 ns] |
|||||||||||||||
This table header & footer: |
- ↑ mAs – Excited nuclear isomer.
- ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
- ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
- ↑
Modes of decay:
EC: Electron capture n: Neutron emission p: Proton emission - ↑ Bold italics symbol as daughter – Daughter product is nearly stable.
- ↑ Bold symbol as daughter – Daughter product is stable.
- ↑ ( ) spin value – Indicates spin with weak assignment arguments.
- 1 2 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
References
- ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
- ↑ "Standard Atomic Weights: Arsenic". CIAAW. 2013.
- ↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
- Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
- "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
- Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.
- A.Shore, A. Fritsch, M. Heim, A. Schuh, M. Thoennessen. Discovery of the Arsenic Isotopes. arXiv:0902.4361.