Naturally occurring lanthanum (57La) is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138La, with a half-life of 1.02×1011 years; 137La, with a half-life of 60,000 years and 140La, with a half-life of 1.6781 days. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these have half-lives that are less than 1 minute. This element also has 12 nuclear isomers, the longest-lived of which is 132mLa, with a half-life of 24.3 minutes. Lighter isotopes mostly decay to isotopes of barium and heavy ones mostly decay to isotopes of cerium. 138La can decay to both.
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| Standard atomic weight Ar°(La) | ||||||||||||||||||||||||||||
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The isotopes of lanthanum range in atomic weight from 115.96 u (116La) to 154.96 u (155La).
List of isotopes
edit
| Nuclide [n 1] |
Z | N | Isotopic mass (Da) [n 2][n 3] |
Half-life [n 4][n 5] |
Decay mode [n 6] |
Daughter isotope [n 7][n 8] |
Spin and parity [n 9][n 5] |
Natural abundance (mole fraction) | Note | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Excitation energy[n 5] | Normal proportion | Range of variation | |||||||||||||||||
| 116La[4] | 57 | 59 | 50(22) ms | p (~60%) | 115Ba | ||||||||||||||
| β+ (~40%) | 116Ba | ||||||||||||||||||
| 117La | 57 | 60 | 116.95007(43)# | 23.5(26) ms | β+ | 117Ba | (3/2+, 3/2−) | ||||||||||||
| p | 116Ba | ||||||||||||||||||
| 117mLa | 151(12) keV | 10(5) ms | (9/2+) | ||||||||||||||||
| 118La | 57 | 61 | 117.94673(32)# | 200# ms | β+ | 118Ba | |||||||||||||
| 119La | 57 | 62 | 118.94099(43)# | 1# s | β+ | 119Ba | 11/2−# | ||||||||||||
| 120La | 57 | 63 | 119.93807(54)# | 2.8(2) s | β+ | 120Ba | |||||||||||||
| β+, p | 119Cs | ||||||||||||||||||
| 121La | 57 | 64 | 120.93301(54)# | 5.3(2) s | β+ | 121Ba | 11/2−# | ||||||||||||
| β+, p | 120Cs | ||||||||||||||||||
| 122La | 57 | 65 | 121.93071(32)# | 8.6(5) s | β+ | 122Ba | |||||||||||||
| β+, p | 121Cs | ||||||||||||||||||
| 123La | 57 | 66 | 122.92624(21)# | 17(3) s | β+ | 123Ba | 11/2−# | ||||||||||||
| 124La | 57 | 67 | 123.92457(6) | 29.21(17) s | β+ | 124Ba | (7−, 8−) | ||||||||||||
| 124mLa | 100(100)# keV | 21(4) s | low(+#) | ||||||||||||||||
| 125La | 57 | 68 | 124.920816(28) | 64.8(12) s | β+ | 125Ba | (11/2−) | ||||||||||||
| 125mLa | 107.0(10) keV | 390(40) ms | (3/2+) | ||||||||||||||||
| 126La | 57 | 69 | 125.91951(10) | 54(2) s | β+ | 126Ba | (5)(+#) | ||||||||||||
| 126mLa | 210(410) keV | 20(20) s | (0−, 1−, 2−) | ||||||||||||||||
| 127La | 57 | 70 | 126.916375(28) | 5.1(1) min | β+ | 127Ba | (11/2−) | ||||||||||||
| 127mLa | 14.8(12) keV | 3.7(4) min | β+ | 127Ba | (3/2+) | ||||||||||||||
| IT | 127La | ||||||||||||||||||
| 128La | 57 | 71 | 127.91559(6) | 5.18(14) min | β+ | 128Ba | (5+) | ||||||||||||
| 128mLa | 100(100)# keV | <1.4 min | IT | 128La | (1+, 2−) | ||||||||||||||
| 129La | 57 | 72 | 128.912693(22) | 11.6(2) min | β+ | 129Ba | 3/2+ | ||||||||||||
| 129mLa | 172.1(4) keV | 560(50) ms | IT | 129La | 11/2− | ||||||||||||||
| 130La | 57 | 73 | 129.912369(28) | 8.7(1) min | β+ | 130Ba | 3(+) | ||||||||||||
| 131La | 57 | 74 | 130.91007(3) | 59(2) min | β+ | 131Ba | 3/2+ | ||||||||||||
| 131mLa | 304.52(24) keV | 170(10) μs | 11/2− | ||||||||||||||||
| 132La | 57 | 75 | 131.91010(4) | 4.8(2) h | β+ | 132Ba | 2− | ||||||||||||
| 132mLa | 188.18(11) keV | 24.3(5) min | IT (76%) | 132La | 6− | ||||||||||||||
| β+ (24%) | 132Ba | ||||||||||||||||||
| 133La | 57 | 76 | 132.90822(3) | 3.912(8) h | β+ | 133Ba | 5/2+ | ||||||||||||
| 134La | 57 | 77 | 133.908514(21) | 6.45(16) min | β+ | 134Ba | 1+ | ||||||||||||
| 135La | 57 | 78 | 134.906977(11) | 19.5(2) h | β+ | 135Ba | 5/2+ | ||||||||||||
| 136La | 57 | 79 | 135.90764(6) | 9.87(3) min | β+ | 136Ba | 1+ | ||||||||||||
| 136mLa | 255(9) keV | 114(3) ms | IT | 136La | (8)(−#) | ||||||||||||||
| 137La | 57 | 80 | 136.906494(14) | 6(2)×104 y | EC | 137Ba | 7/2+ | extinct | |||||||||||
| 138La[n 10] | 57 | 81 | 137.907112(4) | 1.03(1)×1011 y | β+ (65.5(4)%) | 138Ba | 5+ | 9.0(1)×10−4 | |||||||||||
| β− (34.5(4)%) | 138Ce | ||||||||||||||||||
| 138mLa | 72.57(3) keV | 116(5) ns | (3)+ | ||||||||||||||||
| 139La[n 11] | 57 | 82 | 138.9063533(26) | Stable | 7/2+ | 0.99910(1) | |||||||||||||
| 140La[n 11] | 57 | 83 | 139.9094776(26) | 1.6781(3) d | β− | 140Ce | 3− | ||||||||||||
| 141La | 57 | 84 | 140.910962(5) | 3.92(3) h | β− | 141Ce | (7/2+) | ||||||||||||
| 142La | 57 | 85 | 141.914079(6) | 91.1(5) min | β− | 142Ce | 2− | ||||||||||||
| 143La | 57 | 86 | 142.916063(17) | 14.2(1) min | β− | 143Ce | (7/2)+ | ||||||||||||
| 144La | 57 | 87 | 143.91960(5) | 40.8(4) s | β− | 144Ce | (3−) | ||||||||||||
| 145La | 57 | 88 | 144.92165(10) | 24.8(20) s | β− | 145Ce | (5/2+) | ||||||||||||
| 146La | 57 | 89 | 145.92579(8) | 6.27(10) s | β− (99.99%) | 146Ce | 2− | ||||||||||||
| β−, n (.007%) | 145Ce | ||||||||||||||||||
| 146mLa | 130(130) keV | 10.0(1) s | β− | 146Ce | (6−) | ||||||||||||||
| 147La | 57 | 90 | 146.92824(5) | 4.015(8) s | β− (99.96%) | 147Ce | (5/2+) | ||||||||||||
| β−, n (.04%) | 146Ce | ||||||||||||||||||
| 148La | 57 | 91 | 147.93223(6) | 1.26(8) s | β− (99.85%) | 148Ce | (2−) | ||||||||||||
| β−, n (.15%) | 147Ce | ||||||||||||||||||
| 149La | 57 | 92 | 148.93473(34)# | 1.05(3) s | β− (98.6%) | 149Ce | 5/2+# | ||||||||||||
| β−, n (1.4%) | 148Ce | ||||||||||||||||||
| 150La | 57 | 93 | 149.93877(43)# | 510(30) ms | β− (97.3%) | 150Ce | (3+) | ||||||||||||
| β−, n (2.7%) | 149Ce | ||||||||||||||||||
| 151La | 57 | 94 | 150.94172(43)# | 300# ms [>300 ns] | β− | 151Ce | 5/2+# | ||||||||||||
| 152La | 57 | 95 | 151.94625(43)# | 200# ms [>300 ns] | β− | 152Ce | |||||||||||||
| 153La | 57 | 96 | 152.94962(64)# | 150# ms [>300 ns] | β− | 153Ce | 5/2+# | ||||||||||||
| 154La | 57 | 97 | 153.95450(64)# | 100# ms | β− | 154Ce | |||||||||||||
| 155La | 57 | 98 | 154.95835(86)# | 60# ms | β− | 155Ce | 5/2+# | ||||||||||||
| This table header & footer: | |||||||||||||||||||
- ^ mLa – 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).
- ^ Bold half-life – nearly stable, half-life longer than age of universe.
- ^ a b c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^
Modes of 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.
- ^ Primordial radionuclide
- ^ a b Fission product
References
edit- ^ 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: Lanthanum". CIAAW. 2005.
- ^ 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.
- ^ Zhang, Wei; Cederwall, Bo; Aktas, Özge; Liu, Xiaoyu; Ertoprak, Aysegül; Nyberg, Ayse; Auranen, Kalle; Alayed, Betool; Badran, Hussam; Boston, Helen; Doncel, Maria; Forsberg, Ulrika; Grahn, Tuomas; Greenlees, Paul T.; Guo, Song; Heery, Jacob; Hilton, Joshua; Jenkins, David; Julin, Rauno; Juutinen, Sakari; Luoma, Minna; Neuvonen, Olavi; Ojala, Joonas; Page, Robert D.; Pakarinen, Janne; Partanen, Jari; Paul, Edward S.; Petrache, Costel; Rahkila, Panu; Ruotsalainen, Panu; Sandzelius, Mikael; Sarén, Jan; Szwec, Stuart; Tann, Holly; Uusitalo, Juha; Wadsworth, Robert (14 November 2022). "Observation of the proton emitter 116
57La
59" (PDF). Communications Physics. 5 (1): 1–8. doi:10.1038/s42005-022-01069-w. ISSN 2399-3650. S2CID 253512231.
- 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.