NeptuniumIn 1940, discovery of element 93, neptunium (symbol Np) was announced by Edwin M. McMillan and Philip H. Abelson working at the University of California at Berkeley. While studying nuclear fission, McMillan had discovered neptunium as a decay product of uranium-239 by beta decay. They were able to prove that its chemical and nuclear properties were unique, and thus a new element. Its later isolation in metallic form (Oct 1944) provided final proof. It was named neptunium after Neptune, the planet immediately beyond Uranus. As the first element heavier than uranium, it was called a transuranium element. For his discovery, McMillan was awarded a share of the Nobel Prize for Chemistry in 1951. Later, when discovered, element 94 was named plutonium, for the planet beyond Neptune.«[Image: McMillan recreating the search for neptunium at the time of the announcement of the discovery] |
