Assertion: neptunium's isotope | /r/CreatedBy | glenn t. seaborg
Facets:
value: in 1942
type: TEMPORAL
Source sentences:
text: However, a long-lived isotope of neptunium, neptunium-237 was produced by Glenn T. Seaborg and A. C. Wahl in 1942 while bombarding uranium-238 with fast neutrons in a 60-inch cyclotron.