Naturally occurring barium (56Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001.[4] This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×1021 years (about 1011 times the age of the universe).
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| Standard atomic weight Ar°(Ba) | |||||||||||||||||||||||||||||||||||||||||||||||||||
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There are a total of thirty-three known radioisotopes in addition to 130Ba. The longest-lived of these is 133Ba, which has a half-life of 10.51 years. All other radioisotopes have half-lives shorter than two weeks. The longest-lived isomer is 133mBa, which has a half-life of 38.9 hours. The shorter-lived 137mBa (half-life 2.55 minutes) arises as the decay product of the common fission product caesium-137.
Barium-114 is predicted to undergo cluster decay, emitting a nucleus of stable 12C to produce 102Sn. However this decay is not yet observed; the upper limit on the branching ratio of such decay is 0.0034%.
List of isotopes
edit
| Nuclide [n 1] |
Z | N | Isotopic mass (Da)[5] [n 2][n 3] |
Half-life[1] |
Decay mode[1] [n 4] |
Daughter isotope [n 5][n 6] |
Spin and parity[1] [n 7][n 8] |
Natural abundance (mole fraction) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Excitation energy | Normal proportion[1] | Range of variation | |||||||||||||||||
| 114Ba | 56 | 58 | 113.95072(11) | 460(125) ms | β (79%) | 114Cs | 0 | ||||||||||||
| α (0.9%) | 110Xe | ||||||||||||||||||
| β , p (20%) | 113Xe | ||||||||||||||||||
| CD (<.0034%) | 102Sn, 12C | ||||||||||||||||||
| 115Ba | 56 | 59 | 114.94748(22)# | 0.45(5) s | β | 115Cs | 5/2 # | ||||||||||||
| β , p (>15%) | 114Xe | ||||||||||||||||||
| 116Ba | 56 | 60 | 115.94162(22)# | 1.3(2) s | β (97%) | 116Cs | 0 | ||||||||||||
| β , p (3%) | 115Xe | ||||||||||||||||||
| 117Ba | 56 | 61 | 116.93832(27) | 1.75(7) s | β (87%) | 117Cs | (3/2 ) | ||||||||||||
| β , p (13%) | 116Xe | ||||||||||||||||||
| β , α (0.024%) | 113I | ||||||||||||||||||
| 118Ba | 56 | 62 | 117.93323(22)# | 5.2(2) s | β | 118Cs | 0 | ||||||||||||
| 119Ba | 56 | 63 | 118.93066(21) | 5.4(3) s | β (75%) | 119Cs | (5/2 ) | ||||||||||||
| β , p (25%) | 118Xe | ||||||||||||||||||
| 120Ba | 56 | 64 | 119.92604(32) | 24(2) s | β | 120Cs | 0 | ||||||||||||
| 121Ba | 56 | 65 | 120.92405(15) | 29.7(15) s | β (99.98%) | 121Cs | 5/2 | ||||||||||||
| β , p (0.02%) | 120Xe | ||||||||||||||||||
| 122Ba | 56 | 66 | 121.91990(3) | 1.95(15) min | β | 122Cs | 0 | ||||||||||||
| 123Ba | 56 | 67 | 122.918781(13) | 2.7(4) min | β | 123Cs | 5/2 | ||||||||||||
| 123mBa | 120.95(8) keV | 830(60) ns | IT | 123Ba | 1/2 # | ||||||||||||||
| 124Ba | 56 | 68 | 123.915094(13) | 11.0(5) min | β | 124Cs | 0 | ||||||||||||
| 125Ba | 56 | 69 | 124.914472(12) | 3.3(3) min | β | 125Cs | 1/2 | ||||||||||||
| 125mBa | 120(20)# keV | 2.76(14) μs | IT | 125Ba | (7/2−) | ||||||||||||||
| 126Ba | 56 | 70 | 125.911250(13) | 100(2) min | β | 126Cs | 0 | ||||||||||||
| 127Ba | 56 | 71 | 126.911091(12) | 12.7(4) min | β | 127Cs | 1/2 | ||||||||||||
| 127mBa | 80.32(11) keV | 1.93(7) s | IT | 127Ba | 7/2− | ||||||||||||||
| 128Ba | 56 | 72 | 127.9083524(17) | 2.43(5) d | EC | 128Cs | 0 | ||||||||||||
| 129Ba | 56 | 73 | 128.908683(11) | 2.23(11) h | β | 129Cs | 1/2 | ||||||||||||
| 129mBa | 8.42(6) keV | 2.135(10) h | β | 129Cs | 7/2 | ||||||||||||||
| IT | 129Ba | ||||||||||||||||||
| 130Ba[n 9] | 56 | 74 | 129.9063260(3) | ≈ 1×1021 y | 2EC? | 130Xe | 0 | 0.0011(1) | |||||||||||
| 130mBa | 2475.12(18) keV | 9.54(14) ms | IT | 130Ba | 8− | ||||||||||||||
| 131Ba | 56 | 75 | 130.9069463(4) | 11.52(1) d | β | 131Cs | 1/2 | ||||||||||||
| 131mBa | 187.995(9) keV | 14.26(9) min | IT | 131Ba | 9/2− | ||||||||||||||
| 132Ba | 56 | 76 | 131.9050612(11) | Observationally Stable[n 10] | 0 | 0.0010(1) | |||||||||||||
| 133Ba | 56 | 77 | 132.9060074(11) | 10.5379(16) y | EC | 133Cs | 1/2 | ||||||||||||
| 133mBa | 288.252(9) keV | 38.90(6) h | IT (99.99%) | 133Ba | 11/2− | ||||||||||||||
| EC (0.0104%) | 133Cs | ||||||||||||||||||
| 134Ba | 56 | 78 | 133.90450825(27) | Stable | 0 | 0.0242(15) | |||||||||||||
| 134mBa | 2957.2(5) keV | 2.61(13) μs | IT | 134Ba | 10 | ||||||||||||||
| 135Ba | 56 | 79 | 134.90568845(26) | Stable | 3/2 | 0.0659(10) | |||||||||||||
| 135m1Ba | 268.218(20) keV | 28.11(2) h | IT | 135Ba | 11/2− | ||||||||||||||
| 135m2Ba | 2388.0(5) keV | 1.06(4) ms | IT | 135Ba | (23/2 ) | ||||||||||||||
| 136Ba | 56 | 80 | 135.90457580(26) | Stable | 0 | 0.0785(24) | |||||||||||||
| 136m1Ba | 2030.535(18) keV | 308.4(19) ms | IT | 136Ba | 7− | ||||||||||||||
| 136m2Ba | 3357.19(25) keV | 91(2) ns | IT | 136Ba | 10 | ||||||||||||||
| 137Ba | 56 | 81 | 136.90582721(27) | Stable | 3/2 | 0.1123(23) | |||||||||||||
| 137m1Ba | 661.659(3) keV | 2.552(1) min | IT | 137Ba | 11/2− | ||||||||||||||
| 137m2Ba | 2349.1(5) keV | 589(20) ns | IT | 137Ba | (19/2−) | ||||||||||||||
| 138Ba[n 11] | 56 | 82 | 137.90524706(27) | Stable | 0 | 0.7170(29) | |||||||||||||
| 138mBa | 2090.536(21) keV | 850(100) ns | IT | 138Ba | 6 | ||||||||||||||
| 139Ba[n 11] | 56 | 83 | 138.90884116(27) | 82.93(9) min | β− | 139La | 7/2− | ||||||||||||
| 140Ba[n 11] | 56 | 84 | 139.910608(8) | 12.7534(21) d | β− | 140La | 0 | ||||||||||||
| 141Ba[n 11] | 56 | 85 | 140.914404(6) | 18.27(7) min | β− | 141La | 3/2− | ||||||||||||
| 142Ba[n 11] | 56 | 86 | 141.916433(6) | 10.6(2) min | β− | 142La | 0 | ||||||||||||
| 143Ba[n 11] | 56 | 87 | 142.920625(7) | 14.5(3) s | β− | 143La | 5/2− | ||||||||||||
| 144Ba[n 11] | 56 | 88 | 143.922955(8) | 11.73(8) s | β− | 144La | 0 | ||||||||||||
| 145Ba | 56 | 89 | 144.927518(9) | 4.31(16) s | β− | 145La | 5/2− | ||||||||||||
| 146Ba | 56 | 90 | 145.9303632(19) | 2.15(4) s | β− | 146La | 0 | ||||||||||||
| 147Ba | 56 | 91 | 146.935304(21) | 893(1) ms | β− (99.93%) | 147La | 5/2− | ||||||||||||
| β−, n (0.07%) | 146La | ||||||||||||||||||
| 148Ba | 56 | 92 | 147.9382230(16) | 620(5) ms | β− (99.6%) | 148La | 0 | ||||||||||||
| β−, n (0.4%) | 147La | ||||||||||||||||||
| 149Ba | 56 | 93 | 148.9432840(27) | 349(4) ms | β− (96.1%) | 149La | 3/2−# | ||||||||||||
| β−, n (3.9%) | 148La | ||||||||||||||||||
| 150Ba | 56 | 94 | 149.946441(6) | 258(5) ms | β− (99.0%) | 150La | 0 | ||||||||||||
| β−, n (1.0%) | 149La | ||||||||||||||||||
| 151Ba | 56 | 95 | 150.95176(43)# | 167(5) ms | β− | 151La | 3/2−# | ||||||||||||
| β−, n? | 150La | ||||||||||||||||||
| 152Ba | 56 | 96 | 151.95533(43)# | 139(8) ms | β− | 152La | 0 | ||||||||||||
| β−, n? | 151La | ||||||||||||||||||
| 153Ba | 56 | 97 | 152.96085(43)# | 113(39) ms | β− | 153La | 5/2−# | ||||||||||||
| β−, n? | 152La | ||||||||||||||||||
| β−, 2n? | 151La | ||||||||||||||||||
| 154Ba | 56 | 98 | 153.96466(54)# | 53(48) ms | β− | 154La | 0 | ||||||||||||
| This table header & footer: | |||||||||||||||||||
- ^ mBa – 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:
CD: Cluster decay EC: Electron capture IT: Isomeric transition 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.
- ^ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^ Primordial radioisotope
- ^ Believed to undergo β β decay to 132Xe with a half-life over 3×1020 years
- ^ a b c d e f g Fission product
References
edit- ^ a b c d e 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: Barium". CIAAW. 1985.
- ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (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.
- ^ Meshik, A.P.; Hohenberg, C.M.; Pravdivtseva, O.V.; Kapusta, Y.S. (2001). "Weak decay of 130Ba and 132Ba: Geochemical measurements". Physical Review C. 64 (3): 035205–1–035205–6. Bibcode:2001PhRvC..64c5205M. doi:10.1103/PhysRevC.64.035205.
- ^ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
- 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.
- Half-life of 130Ba from:
- A. P. Meshik; C. M. Hohenberg; O. V. Pravdivtseva; Ya. S. Kapusta (2001). "Weak decay of 130Ba and 132Ba: Geochemical measurements". Physical Review C. 64 (3): 035205 [6 pages]. Bibcode:2001PhRvC..64c5205M. doi:10.1103/PhysRevC.64.035205.
- M. Pujol; B. Marty; P. Burnard; P. Philippot (2009). "Xenon in Archean barite: Weak decay of 130Ba, mass-dependent isotopic fractionation and implication for barite formation". Geochimica et Cosmochimica Acta. 73 (22): 6834–6846. Bibcode:2009GeCoA..73.6834P. doi:10.1016/j.gca.2009.08.002.