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The Production of Transuranic Elements

1945 - 1974

The Radiation Laboratory (now Lawrence Berkeley National Laboratory) at the University of California, Berkeley, led principally by Edwin McMillan, Glenn Seaborg, and Albert Ghiorso, during 1945-1974:

93	Np	neptunium	named after the planet Neptune, as it follows uranium and Neptune follows Uranus in the planetary sequence	1940
94	Pu	plutonium	named after the dwarf planet Pluto, following the same naming rule as it follows neptunium and Pluto follows Neptune in the pre-2006 planetary sequence	1940
95	Am	americium	named because it is an analog to europium, and so was named after the continent where it was first produced	1944
96	Cm	curium	named after Pierre and Marie Curie, famous scientists who separated out the first radioactive elements	1944
97	Bk	berkelium	named after the city of Berkeley, where the University of California, Berkeley is located	1949
98	Cf	californium	named after the state of California, where the university is located	1950
99	Es	einsteinium	named after the theoretical physicist Albert Einstein	1952
100	Fm	fermium	named after Enrico Fermi, the physicist who produced the first controlled chain reaction	1952
101	Md	mendelevium	named after the Russian chemist Dmitri Mendeleev, credited for being the primary creator of the periodic table of the chemical elements	1955
102	No	nobelium	named after Alfred Nobel	1956
103	Lr	lawrencium	named after Ernest O. Lawrence, a physicist best known for development of the cyclotron, and the person for whom the Lawrence Livermore National Laboratory and the Lawrence Berkeley National Laboratory (which hosted the creation of these transuranium elements) are named	1961
104	Rf	rutherfordium	named after Ernest Rutherford, who was responsible for the concept of the atomic nucleus. This discovery was also claimed by the Joint Institute for Nuclear Research (JINR) in Dubna, Russia (then in the Soviet Union), led principally by G. N. Flerov	1968
105	Db	dubnium	an element that is named after the city of Dubna, where the JINR is located. Originally named "hahnium" in honor of Otto Hahn (1970) but renamed by the International Union of Pure and Applied Chemistry. This discovery was also claimed by the JINR.	1970
106	Sg	seaborgium	named after Glenn T. Seaborg. This name caused controversy because Seaborg was still alive, but eventually became accepted by international chemists. This discovery was also claimed by the JINR.	1974

1980 - 2000

The Gesellschaft für Schwerionenforschung (Society for Heavy Ion Research) in Darmstadt, Hessen, Germany, led principally by Peter Armbruster and Sigurd Hofmann, during 1980-2000:

107	Bh	bohrium	named after the Danish physicist Niels Bohr, important in the elucidation of the structure of the atom. This discovery was also claimed by the JINR.	1981
108	Hs	hassium	named after the Latin form of the name of Hessen, the German Bundesland where this work was performed	1984
109	Mt	meitnerium	named after Lise Meitner, an Austrian physicist who was one of the earliest scientists to study nuclear fission	1982
110	Ds	darmstadtium	named after Darmstadt, Germany, the city in which this work was performed. 111. , , (). 112. , , (). The Joint Institute for Nuclear Research (JINR) in Dubna, Russia, led principally by Y. Oganessian, in collaboration with several other laboratories including the Lawrence Livermore Nation al Laboratory (LLNL), since 2000:	1994
111	Rg	roentgenium	named after Wilhelm Conrad Röntgen, discoverer of X-rays	1994
112	Cn	copernicium	named after astronomer Nicolaus Copernicus	1996

2000 onwards

The Joint Institute for Nuclear Research (JINR) in Dubna, Russia, led principally by Y. Oganessian, in collaboration with several other laboratories including the Lawrence Livermore Nation al Laboratory (LLNL), since 2000:

113	Uut	ununtrium,	temporary name	2003
114	Fl	flerovium	named after Soviet physicist Georgy Flyorov, founder of the JINR	1999
115	Uup	ununpentium	temporary name	2003
116	Lv	livermorium	named after the Lawrence Livermore National Laboratory, a collaborator with JINR in the discovery	2000
117	Uus	ununseptium	temporary name	2010
118	Uuo	ununoctium	temporary name	2002

The temporary names listed above are generic names assigned according to a convention (the systematic element names). They will be replaced by permanent names as the elements are confirmed by independent work.