American chemist · 1918–2005
Jacob A. Marinsky
Jacob Marinsky was one of three chemists at Oak Ridge who finally pinned down element 61, promethium, in 1945, after decades of false claims.
How Promethium was found
Element 61 has no stable isotopes, so the tiny amounts that exist in ores had defeated every earlier search. Marinsky, Glendenin and Coryell looked instead in the fission products of uranium from the Clinton Laboratories reactor.
Marinsky ran the ion-exchange columns that separated the neighbouring rare earths, which are nearly impossible to tell apart chemically. A radioactive band appeared exactly where element 61 should be. The discovery was announced in 1947, after wartime secrecy was lifted.
Shared the credit
The discovery is credited jointly to these scientists.
Life and career
Born 1918 · Died 2005
After the war Marinsky earned his PhD at the Massachusetts Institute of Technology. He spent most of his career as professor of chemistry at the University at Buffalo, specialising in ion exchange.
Discovered in the same era
Other elements identified within ten years of 1945.