American chemist · 1912–1976
Stanley G. Thompson
Stanley Thompson was the chemist who made Berkeley’s heavy-element discoveries possible. He co-discovered berkelium, californium and mendelevium and devised the process that first separated plutonium on an industrial scale.
- Elements credited
- 3
- Discoveries
- 1949–1955
- Co-discoverers
- 5
- Where
- United States
Discovery timeline
1949 · United States
Berkelium is a radioactive metal made only in tiny amounts in high-flux nuclear reactors.
1950 · United States
Californium is a radioactive metal and an intense neutron source. It is one of the most expensive materials ever made.
1955 · United States
Mendelevium is a synthetic radioactive element named after the father of the periodic table.
The discoveries
New actinides are made in tiny amounts mixed with much larger quantities of their neighbours. Thompson specialised in the ion-exchange chemistry that separates them. In 1949 he helped identify berkelium, made by bombarding americium with helium nuclei, and in 1950 californium, made from curium.
In 1955 he was part of the team that made mendelevium and identified its first atoms one by one using the ion-exchange columns he had refined.
Life and career
Thompson grew up in Los Angeles and went to high school with Glenn Seaborg, who later recruited him. During the Manhattan Project he invented the bismuth phosphate process used at Hanford to extract plutonium from irradiated uranium.
He earned his PhD at Berkeley after the war and worked at the Lawrence Radiation Laboratory for the rest of his life, studying nuclear fission.
Also known for
- The bismuth phosphate process for separating plutonium