Radiochemical Detection of Barium from Neutron-Irradiated Uranium

Hahn & Strassmann, "Uber den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle" (Die Naturwissenschaften 27, 11-15; Crossref publication date January 1939; DOI 10.1007/BF01488241). Chemical evidence that neutron-irradiated uranium yields an alkaline-earth element chemically identical to barium, far lighter than uranium -- inconsistent with the prevailing expectation that neutron capture would produce transuranic elements. This is the experimental discovery; Hahn and Strassmann did not themselves supply the physical explanation (see the Meitner-Frisch node). Otto Hahn alone received the 1944 Nobel Prize in Chemistry "for his discovery of the fission of heavy nuclei" (verified at nobelprize.org API 2026-10-18); Strassmann and Meitner were not named, a documented credit dispute this node records without adjudicating. Anchored to publication year 1939; the manuscript submission date of December 1938 is widely reported but was not verified live here, so it is not used for dating. OpenAlex stores the title with a corrupted umlaut; the Crossref DOI is authoritative.