Artificial radioactive element properties unknown	memory peg (for Hahnium)
	1968 Г.Н.Флеров (G.N. Flerov) and co-workers, Dubna, Russia 1970 Albert Ghiorso and co-workers, Berkeley, Calif., USA
	Dubna group named it Nielsbohrium, the Berkeley group Hahnium, in 1997 named Dubnium after Дубна (Dubna), town in Moscow region

First preparation by Russian and American teams:

• 1968 by Г.Н. Флеров (Georgy Nikolaevich Flerov), V.A. Druin, A.G. Demin, Ю.В. Лобанов (Yu.V. Lobanov), Nikolai Konstantinovich Skobelev, G.N. Akap'ev, B.V. Fefilov, I.V. Kolesov, K.A. Gavrilov, Ю. П. Харитонов (Yu.P. Kharitonov), and L.P. Chelnokov at the Объединенный Институт Ядерных Исследований (ОИЯИ) - Joint Institute for Nuclear Research (JINR) at Дубна (Dubna) by bombardment of Americium with Neon ions and named Nielsbohrium after Niels Bohr (cf. Bohrium).
• 1970 by Albert Ghiorso, M. Nurmia, K. Eskola, J. Harris, and P. Eskola at the Berkeley Laboraty of the University of California by bombardment of Californium with Nitrogen ions and named Hahnium after Otto Hahn (1879-1968) (cf. Hassium).

The systematic IUPAC name was Unnilpentium (Unp). In 1994 IUPAC proposed the name Joliotium (Jl) for element #105 "to recognize the French scientist F. Joliot-Curie who contributed greatly to the development of nuclear physics and chemistry, and who shared the Nobel prize in 1935 with Mme. M. Curie", and for element #104 Dubnium "to recognize the distinguished contributions to chemistry and modern nuclear physics of the international scientific centre at Dubna near Moscow." The American Chemical Society kept the name Hahnium (Ha), as proposed by Ghiorso and co-workers. In 1997, at the final elements christening during the International Union of Pure and Applied Chemistry (IUPAC) Council meeting in Geneva, element #104 was named Rutherfordium and element #105 got the name and symbol Dubnium (Db) (see "Naming the transfermium elements" on the Mendelevium page).

After the town of Дубна (Dubna), a small town north of Moscow region (127 km from Moscow) where the Moscow Canal flows from the Volga River. The town is well-known in Russia and abroad as a city of science, due to Объединенный Институт Ядерных Исследований (ОИЯИ) (Joint Institute for Nuclear Research, JINR). This institute is heavily involved in the search for heavy elements (see also Here is a photo-album of Dubna).

Variant names of elements 104-108
No.	syst. IUPAC	IUPAC 1997	proposals
104	Unq Unnilquadium	Rf Rutherfordium	Db Dubnium (1) Ku Kurchatovium (3)
105	Unp Unnilpentium	Db Dubnium	Jo Joliotium (1) Ha Hahnium (2) Ns Nielsbohrium (3)
106	Unh Unnilhexium	Sg Seaborgium	Rf Rutherfordium (1)
107	Uns Unnilseptium	Bh Bohrium (1)	Ns Nielsbohrium (2, 4)
108	Uno Unniloctium	Hs Hassium (4)	Ha Hahnium (1)
(1) IUPAC 1994; (2) ACS 1994; (3) ОИЯИ (JINR); (4) GSI 1992 See "Naming the transfermium elements" on the Mendelevium page

Further reading:

• 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.