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Although arsenic (As) has multiple isotopes, only one of these isotopes is stable; as such, it is considered a monoisotopic element. 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 of gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several hours.citation needed Such a weapon is not known to have ever been built, tested, or used.
Standard atomic mass: 74.92160(2) u.
Table
| nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life | nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|
| excitation energy | |||||||
| 60As | 33 | 27 | 59.99313(64)# | 5+# | |||
| 61As | 56 | 28 | 60.98062(64)# | 3/2-# | |||
| 62As | 33 | 29 | 61.97320(32)# | 1+# | |||
| 63As | 33 | 30 | 62.96369(54)# | (3/2-)# | |||
| 64As | 33 | 31 | 63.95757(38)# | 40(30) ms [18(+43-7) ms] | 0+# | ||
| 65As | 33 | 32 | 64.94956(32)# | 170(30) ms | 3/2-# | ||
| 66As | 33 | 33 | 65.94471(73) | 95.77(23) ms | (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 | (5/2-) | ||
| 68As | 33 | 35 | 67.93677(5) | 151.6(8) s | 3+ | ||
| 68mAs | 425.21(16) keV | 111(20) s [?107(+23-16) ns] | 1+ | ||||
| 69As | 33 | 36 | 68.93227(3) | 15.2(2) min | 5/2- | ||
| 70As | 33 | 37 | 69.93092(5) | 52.6(3) min | 4(+#) | ||
| 70mAs | 32.008(23) keV | 96(3) µs | 2(+) | ||||
| 71As | 33 | 38 | 70.927112(5) | 65.28(15) h | 5/2- | ||
| 72As | 33 | 39 | 71.926752(5) | 26.0(1) h | 2- | ||
| 73As | 33 | 40 | 72.923825(4) | 80.30(6) d | 3/2- | ||
| 74As | 33 | 41 | 73.9239287(25) | 17.77(2) d | 2- | ||
| 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 | 2- | ||
| 76mAs | 44.425(1) keV | 1.84(6) µs | (1)+ | ||||
| 77As | 33 | 44 | 76.9206473(25) | 38.83(5) h | 3/2- | ||
| 77mAs | 475.443(16) keV | 114.0(25) µs | 9/2+ | ||||
| 78As | 33 | 45 | 77.921827(11) | 90.7(2) min | 2- | ||
| 79As | 33 | 46 | 78.920948(6) | 9.01(15) min | 3/2- | ||
| 79mAs | 772.81(6) keV | 1.21(1) µs | (9/2)+ | ||||
| 80As | 33 | 47 | 79.922534(25) | 15.2(2) s | 1+ | ||
| 81As | 33 | 48 | 80.922132(6) | 33.3(8) s | 3/2- | ||
| 82As | 33 | 49 | 81.92450(21) | 19.1(5) s | (1+) | ||
| 82mAs | 250(200) keV | 13.6(4) s | (5-) | ||||
| 83As | 33 | 50 | 82.92498(24) | 13.4(3) s | 3/2-# | ||
| 84As | 33 | 51 | 83.92906(32)# | 4.02(3) s | (3)(+#) | ||
| 84mAs | 0(100)# keV | 650(150) ms | |||||
| 85As | 33 | 52 | 84.93202(21)# | 2.021(10) s | (3/2-)# | ||
| 86As | 33 | 53 | 85.93650(32)# | 0.945(8) s | |||
| 87As | 33 | 54 | 86.93990(32)# | 0.56(8) s | 3/2-# | ||
| 88As | 33 | 55 | 87.94494(54)# | 300# ms [>300 ns] | |||
| 89As | 33 | 56 | 88.94939(54)# | 200# ms [>300 ns] | 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] | |||
Notes
- Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
- Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.
References
- Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
- Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
- Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
- Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
- National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
- David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.
| Isotopes of germanium | Isotopes of arsenic | Isotopes of selenium |
| Index to isotope pages · Table of nuclides | ||
Wikipedia content modification information:
- This page was last modified on 9 June 2008, at 04:39.
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