Dubnium

The discoveries of all three of these elements were made at the beginning of the nineteenth century and were marked by initial uncertainty and confusion due, in the case of the heavier pair of elements, to the overriding similarity of their chemistries. (See p. 1282 for element 105, dubnium.)... 

Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium ... 

Francium Radium Actinium Rutherfordiurr Dubnium Seaborgiurr Bohrium Hassium Meitnerium... 

Dual nickel, 9 820—821 Dual-pressure processes, in nitric acid production, 17 175, 177, 179 Dual-solvent fractional extraction, 10 760 Dual Ziegler catalysts, for LLDPE production, 20 191 Dubinin-Radushkevich adsorption isotherm, 1 626, 627 Dubnium (Db), l 492t Ductile (nodular) iron, 14 522 Ductile brittle transition temperature (DBTT), 13 487 Ductile cast iron, 22 518—519 Ductile fracture, as failure mechanism, 26 983 Ductile iron... 

Dubnium - the atomic number is 105 and the chemical symbol is Db. The name derives from the location of the Russian research center, the Joint Institute for Nuclear Research lab in Dubna , Russia. The first synthesis of this element is jointly credited to the American scientific team at the University of California in Berkeley, California imder Albert Ghiorso and the Russian scientific team at the JINR (Joint Institute for Nuclear Reactions) lab in Dubna, Russia, imder Georgi N. Flerov in 1970. The longest half-life associated with this unstable element is 34 second Db. 

ORIGIN OF NAME Unnilquadium follows the transitional naming system of lUPAC but originally was named "hahnium" by the Berkeley group in honor of Otto Hahn, who discovered nuclear fission. The American Chemical Society endorsed the name "hahnium" for element 105, but as the Berkeley group continued its work and more isotopes of Q Unp were formed, the lUPAC changed the name "hahnium" to "dubnium" after the city Dubna, Russia, where the first isotopes of unnilpentium were formed. 

ISOTOPES There are a total of 15 isotopes of unnilpentium (dubnium). Their half-lives range from 0.76 seconds (for Db-257) to 16 hours (for Db-268). All of them decay by spontaneous fission and alpha decay. 

Dubnium s (Unp) most stable isotope, Db-268, is unstable with a half-life of 16 houts. It can change into lawtencium-254 by alpha decay ot into tuthetfotdium-268 by electton cap-tute. Both of these teactions occut thtough a series of decay processes and spontaneous fission (SF). Since so few atoms of unnilpentium (dubnium) are produced, and they have such a short half-life, its melting point, boiling point, and density cannot be determined. In addition, its valence and oxidation state are also unknown. 

After evidence of the formation of unnilpentium in 1970 by the Berkeley team, the American Chemical Society (ACS) changed the name Unp to hahnium. To settle the confusing claims, the lUPAC recommended that scientists from the Russian and Berkeley groups get together to review and confirm conflicting data. This cooperative venture was never implemented. In 1997 the lUPAC decided to change the name hahnium (j Ha) to dubnium ( jj Db) after the location of the Russian nuclear research lab that first produced the new element. Dubnium is the name by which it is known by today. 

There are no uses for unnilpentium (dubnium) except for research purposes. 

No compounds are pubhshed for unnilpentium (dubnium), but it could possibly form compounds similar to its homologue element 71, tantalum, in group 5. 

The hazards of dubnium are similar to all radioactive heavy metals of the transactinide series, but there is no threat to the public given that such a small amount of the element is produced and exists. 

The two scientists then traced the very short decay sequence of the three Une-266 atoms as they decayed into element 107 (unnilseptium or bohrium) and element number 105 (unnil-pentium or dubnium). The decay sequence is as follows ... 

Dubnium (Unnilpentium) Db or Unp 1967 (Dubna, Russia) Berkeley, California Georgy Flerov (Russian) Albert Ghiorso (American) 343... 

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