Artificial radioactive metal m.p. 640±1 ºC; 1184±0.8 ºF b.p. estimated 3902 ºC; 7056 ºF density 20.25 g/cc; 1264.17 pound/cubic foot	memory peg
	1940 Edwin M. McMillan and Philip Abelson, Berkeley, Calif., USA
	Neptunus, planet, named after the Roman god of the sea.

The element was was first prepared in 1940 by Edwin M. McMillan and Philip Abelson at the Berkeley Laboraty of the University of California by irradiation of Uranium with neutrons.

The first element following Uranium is named after the first planet after Uranus: Neptune.
The planet is named after the Roman god of the sea, Neptunus. His greek equivalent is Ποσeιδων [Poseidōn], after whom the Greeks named the element.

False transuranic elements (#93-97)

Element #93 has got in 1934-38 the preliminary name Eka-Rhenium by Otto Hahn, Lise Meitner and Fritz Strassmann in Germany, who thought they had found traces of several transuranium elements. In December of 1938, Hahn and Strassman found out that these radioactivities were not due to transuranium elements but were due to fission products. According to the Periodic Table of that time, without the Actinide series, element #93 is below Rhenium (#75). According to the present Table, Eka-Rhenium would be #107.

Bohemium & Sequanium (note)

In 1934 the engineer Odolen Koblic (1897-ca.1959), after he processed pitchblende from Jàchymov, in Czechoslovakia, concluded that element 93 was present in it. In summer 1934 Koblic published a short communication in which he stated "All the researches confirm my success in isolating the element of atomic number 93, to whom I give the name Bohemium (Bo) in honour to my fatherland.". Four years later, in 1938, Horia Hulubei (1896-1972) and Yvette Cauchois (1908-1999) distracted from some minerals from Madagascar element 93. They announced it as follows: "Nous aimerions que, si l'existence de cet élément 93 est confirmée, on le nommât Sequanium (Sq), en l'hommage à la vaillante et généreuse civilisation qui a fleuri sur les bordes de la Seine". The Latin name for the Seine is Sequana, thus the element should be named after Cauchois' fatherland - she was born in Paris -, as the element 87 Moldavium (see Francium) was named after Hulubei's fatherland

Ausonium & Hesperium

In 1934, Enrico Fermi (1901-1954) and his co-workers, Edoardo Amaldi (1908-1989), Oscar D'Agostino (1901-1975), Emilio Segrè (1905-1989), and Franco Rasetti (1901-2001), at the University of Rome, bombarded Uranium with neutrons and believed to have synthesized the first transuranium elements. The Dean of the Faculty of Rome, Orso Mario Corbino (1876-1937), announced the discovery of the elements 93 and 94 and he gave prematurely the names and symbols Ausonium, Ao, after Ausonia, the poetic name of Italy, and Hesperium (Esperio), Es (#94), from Hesperius, the Western country (Italy, seen from Greece). The fascist regime of Italy forced him to call one of these elements Littorio (Littorium, after the Italian "littorio", an Imperial Roman symbol re-used during the dictatorship, sometimes this word is associated with the regime itself). Corbino sarcastically replied that it was unlucky for the regime to be associated with an element with half life of few seconds... so the names remained Ausonium and Hesperium (note).

Fermi described this discovery in his Nobel lecture of 1938. Within weeks of the Nobel ceremony, the discovery of nuclear fission was announced. Uranium had been split virtually in half and Fermi's supposed new elements were actually Barium (56) and a mix of Krypton (36) and other elements of similar weight (note) (note2).

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Fountain of Neptune at the Country Club Plaza (Kansas City). The Roman god of the sea and his three attributes, the trident, dolphin and sea-horse, was bought at the cost of scrap metal and placed here. The fountain was originally from Bromsgrove Guild, Worcestershire, England, 1911.

For an older Neptunium, see Niobium and Germanium.

Further reading:

• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 840-842.
• Earl K. Hyde & Glenn T. Seaborg, Transurane : Teil A 1, I: Die Elemente. Gmelins Handbuch der anorganische Chemie, Ergänzungswerk zur 8. Aufl.; Band 7a. Weinheim/Bergstrasse: Chemie, 1973.
• Glenn T. Seaborg, Early History of LBNL, A transcript of the lecture on the 65th Anniversary of Lawrence Berkeley National Laboratory, August 26, 1996 (on-line).
• Darleane C. Hoffman, Albert Ghiorso & Glenn T. Seaborg, The Transuranium People: The Inside Story. Singapore [etc.]: World Scientific Publishing Co., 2000 (on-line information).
• Enrico Fermi, Artificial radioactivity produced by neutron bombardment. Nobel Lecture, 12 December 1938 (on-line PDF-file).