Dubmium

Atomic Weight: 268
Dubnium is named after the town of Dubna in Russia, where it was first produced. It is a synthetic element. The most stable known isotope, Dubnium-268, has a half-life of approximately 28 hours. In the periodic table of the elements, it is a d-block element and in the transactinide elements. It is a member of the 7th period and belongs to the group 5 element. Chemistry experiments have confirmed that Dubnium behaves as the heavier homologue to tantalum in group 5. The chemical properties of Dubnium are characterized only partly. They are similar with those of other group 5 elements. In the 1960s, microscopic amounts of Dubnium were produced in laboratories in the former Soviet Union and in California. The priority of the discovery and the naming of the element was disputed between Soviet and American scientists, and it was not until 1997 that International Union of Pure and Applied Chemistry (IUPAC) established Soviet team priority and a compromise name of Dubnium as the official name for the element. In the 1960s, microscopic amounts of dubnium were produced in laboratories in the former [|Soviet Union] and in [|California]. The priority of the discovery and therefore the [|naming of the element] was disputed between Soviet and American scientists, and it was not until 1997 that [|International Union of Pure and Applied Chemistry] (IUPAC) established Soviet team priority and a compromise name of dubnium as the official name for the element.


 * Name:** Dubnium **Symbol:** Db **Atomic Number:** 105 **Atomic Mass:** (262.0) amu **Melting Point:** Unknown **Boiling Point:** Unknown **Number of Protons/Electrons:** 105 **Number of Neutrons:** 157 **Classification:** Transition Metal **Crystal Structure:** Unknown **Density @ 293 K:** Unknown **Color:** Unknown **Other Names:** Unnilpentium (Unp), Joliotium (Jl), Hahnium (Ha)

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Db-258 || 4.2 seconds ||

Facts

 * Date of Discovery:** 1970 **Discoverer:** Albert Ghiorso **Name Origin:** After Dubna, Russia **Uses:** No uses known **Obtained From:** Man-made

The Soviet (later, Russian) team proposed the name //nielsbohrium// (Ns) in honor of the Danish nuclear physicist [|Niels Bohr]. The American team proposed that the new element should be named //hahnium// (Ha), in honor of the late [|German] chemist [|Otto Hahn]. Consequently //hahnium//was the name that most American and Western European scientists used and appears in many papers published at the time, and//nielsbohrium// was used in the Soviet Union and [|Eastern Bloc] countries. An [|element naming controversy] erupted between the two groups. The [|International Union of Pure and Applied Chemistry] (IUPAC) thus adopted //unnilpentium// (Unp) as a temporary, [|systematic element name]. Attempting to resolve the issue, in 1994, the IUPAC proposed the name //joliotium// (Jl), after the French physicist [|Frédéric Joliot-Curie], which was originally proposed by Soviet team for element 102, later named [|nobelium]. The two principal claimants still disagreed about the names of elements 104-106. However, in 1997 they resolved the dispute and adopted the current name, //dubnium// (Db), after the [|Russian] town of [|Dubna], the location of the [|Joint Institute for Nuclear Research]. It was argued by IUPAC that the Berkeley laboratory had already been recognized several times in the naming of elements (i.e., [|berkelium], [|californium] , [|americium] ) and that the acceptance of the names // [|rutherfordium] // and // [|seaborgium] // for elements 104 and 106 should be offset by recognizing the Russian team's contributions to the discovery of elements 104, 105 and 106. [|[7]][|[8]]

Experimental chemistry
The chemistry of dubnium has been studied for several years using gas thermochromatography. The experiments have studied the relative adsorption characteristics of isotopes of [|niobium], [|tantalum] and dubnium radioisotopes. The results have indicated the formation of typical group 5 halides and oxyhalides, namely DbCl5, DbBr5, DbOCl3 and DbOBr3. Reports on these early experiments usually refer to dubnium as hahnium.