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Isotopes of einsteinium

Open-knowledge reference entry

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionJun 17, 2026
Entity authorityQ785082 ↗
Source-derived summary

Einsteinium (99Es) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be discovered (in nuclear fallout from the Ivy Mike H-bomb test) was 253Es in 1952. There are 18 known radioisotopes, from 240Es to 257Es, and 8 nuclear isomers. The longest-lived isotope is 252Es with a half-life of 471.7 days or 1.291 years; the second longest, 254Es with half-life of 275.7 days is more available.

Editorial summary

This brief starts where responsible research should: with the source description of “Isotopes of einsteinium” 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—1952—that can be checked directly. The selected authority fields contribute no independent date. The account is most persuasive where Isotopes, einsteinium and Open-knowledge can be independently traced.
Editorial analysis

Why this record matters

The subject matters to the general reference register because the source frames it as open-knowledge reference entry. Its deeper value depends on whether names, dates, institutions and citations support that framing.

Evidence profile

Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Jun 17, 2026. The linked authority identifier is Q785082. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1952.

Critical limits

The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.

How to read it

Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.

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Three-step research path

  1. Establish the record: confirm the title “Isotopes of einsteinium”, its source revision and the description used here.
  2. Expand the search: follow Isotopes of einsteinium primary sources, Isotopes of einsteinium archive and Isotopes research across catalogues and specialist indexes.
  3. Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.

Questions for further research

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  2. What terminology or title could unlock a more precise catalogue search?
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Source & attribution

This entry incorporates text from “Isotopes of einsteinium” 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.