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Isotopes of lanthanum

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Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionSep 23, 2026
Entity authorityQ559290 ↗
Source-derived summary

Naturally occurring lanthanum (57La) is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99.911% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138La, with a half-life of 1.03×1011 years; 137La, with a half-life of 60,000 years and 140La, with a half-life of 40.289 hours. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these less than a 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.

The known isotopes of lanthanum range from 116La to 158La.

List of isotopes

See also

Daughter products other than lanthanum

Isotopes of cerium

Isotopes of barium

Isotopes of caesium

References

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)".

Editorial summary

This brief starts where responsible research should: with the source description of “Isotopes of lanthanum” as open-knowledge reference entry. Everything that follows is an evidence route, not borrowed authority.

Editorial reviewA concise reference frame for defining the subject, testing terminology and identifying the institution closest to the evidence. The current lead gives the account dated anchors—1011, 2003, 1016, 2000—that can be checked directly. The selected authority fields contribute no independent date. The account is most persuasive where Isotopes, lanthanum and Open-knowledge can be independently traced.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 23, 2026. The linked authority identifier is Q559290. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1011, 2003, 1016 and 2000.

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This entry incorporates text from “Isotopes of lanthanum” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.