Photo of Edwin M. McMillan

Edwin M. McMillan

  • National Medal of Science
  • Physical Sciences

For his scientific achievements including the identification of the first transuranic element (neptunium) and the invention of the phase stability principle incorporated in the synchrotron.

Edwin M. McMillan made a huge impact on the field of chemistry when he discovered a new element.The chemist produced the element neptunium in 1940, the first transuranium element ever to be discovered. A transuranium element is one with an atomic number greater than 92, the atomic number of uranium.

McMillan and his collaborator Glenn Seaborg named the element after the planet Neptune since it was the next element after uranium, an element named after the planet Uranus.

In 1942, McMillan joined the Manhattan Project, the research effort to develop nuclear weapons during World War II. While working on the initiative, McMillan helped create the Los Alamos National Laboratory, where the world’s first atomic bomb was created. After the war, McMillan became director of the University of California Radiation Laboratory and he remained at the university until his retirement in 1974.

By Rachel Warren