Discovery of Plutonium
Co-discovers plutonium and demonstrates that the periodic table can be extended with additional transuranium elements.
Historical biography archive · Updated 2026-11-03
Glenn Theodore Seaborg Biography and Timeline
Follow Glenn Theodore Seaborg through 9 dated historical records for United States of America.
Glenn Theodore Seaborg, historical timeline
A chronological timeline drawn from matching World History Database records.
9Distinct records
1 of 1Page
1941–1950Years on this page
1941
1942
Pure Plutonium Isolation
Seaborg isolates pure plutonium using a separation method suitable for development on an industrial scale.
Plutonium Neutron Impurity Warning
Seaborg warns that plutonium's alpha activity can make light-element impurities a serious unwanted neutron source.
1943
First Plutonium Metal Sample
The Chicago Metallurgical Laboratory produces the first sample of plutonium in metallic form by chemically reducing plutonium fluoride.
1944
Actinide Concept
Proposes that the heavy elements beginning with actinium form a separate actinide series analogous to the lanthanides, reshaping the lower part of the periodic table.
Discovery of Americium
Co-discovers americium and places it within the newly proposed actinide series of the periodic table.
Discovery of Curium
Co-discovers curium and helps establish the systematic extension of the actinide series beyond plutonium.
1949
Discovery of Berkelium
Co-discovers berkelium, adding element 97 to the actinide series and further extending the periodic table.
1950
Discovery of Californium
Co-discovers californium, element 98, through bombardment experiments and adds another member to the actinide sequence.
Records, sources and methodology
These dates and descriptions come from the historical_events database. Exact duplicate records have been collapsed. Names are grouped by the country, Name 2 and Name 1 fields; records with missing Name 2 cannot be reliably assigned to an individual biography. Check the underlying sources before formal citation.