Isotopes of krypton
isotopes of the element Krypton
There are 34 known isotopes of krypton (36Kr) with atomic mass numbers from 67 to 103. Naturally occurring krypton is made of five stable isotopes and one (78Kr) which is slightly radioactive with an extremely long half-life, plus traces of radioisotopes that are produced by cosmic rays in the atmosphere. Atmospheric krypton today is, however, considerably radioactive due almost entirely to artificial 85Kr.
List of isotopes
Notable isotopes
Krypton-81
Krypton-81 (half-life 230,000 years) is useful in determining how old the water beneath the ground is. Radioactive krypton-81 is the product of spallation reactions with cosmic rays striking gases present in the Earth atmosphere, along with the six stable or nearly stable krypton isotopes. The long half-life ensures that the isotope has a uniform concentration in the atmosphere and in surface water; when the water goes underground is supply is no longer replenished and decays, allowing dating of the residence time in deep aquifers in a range of 20,000 to a million years, bridging the gap where other isotopic methods (e.g. carbon-14 dating) lose sensitivity. The same long half-life renders detection of its decay impossible and, therefore, demands some form of mass spectrometry. Even so, technical limitations of the method have traditionally required the sampling of very large volumes of water: several hundred liters or a few cubic meters of water (about a milligram of krypton). This is particularly challenging for dating pore water in deep clay aquitards with very low hydraulic conductivity.
Begin with the source’s own compact description: “Isotopes of krypton” is isotopes of the element Krypton. The dossier treats that line as a proposition to test through Isotopes, krypton and isotopes, not as a finished interpretation.
Why this record matters
The phrase “isotopes of the element Krypton” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Sep 10, 2026. The linked authority identifier is Q1373439. None of the 0 selected statements returned an explicit reference.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. 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.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Isotopes of krypton”, its source revision and the description used here.
- Expand the search: follow Isotopes of krypton primary sources, Isotopes of krypton archive and Isotopes research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Isotopes of krypton”?
- Which cited source is closest to the event, object or claim?
- What terminology or title could unlock a more precise catalogue search?
Search terms from this dossier
This entry incorporates text from “Isotopes of krypton” 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.