Periodic Table -> Dubnium


Dubnium Details

Dubnium Symbol: Db

Dubnium Atomic Number: 105

Dubnium Atomic Weight: (268)

What is Dubnium?

Dubnium (atomic number 105, symbol Db), is a synthetic chemical element, and its most stable isotope which is dubnium-268, has a half-life of approximately 28 to 30 hours.

At the moment, the chemical properties of unnilpentium are only partially known to scientists, however, they do believe the element will have properties similar to those of other Group 5 elements of the Periodic Table. Currently, the boiling and melting point, as well as the density are still unknown. According to the element classification, Db or Unp is a radioactive metal. At room temperature, the element is in a solid state. This is a transition metal which decomposes quickly because it is unstable. It can be synthetized through hot and cold fusion. Some isotopes have been identified, including Db-256, Db-257, Db-261, Db-266, Db, 270, and others.

As the usual practice at the time was – the discovery and naming of the element was the object of much dispute between former rivals USSR and USA. Officially, minute amounts of unnilpentium were discovered in the 60s and 70s in labs in Dubna, USSR and California, USA. The dispute between Russian and American scientists over who discovered it and whose name it should bear, dragged on for decades, all the way up to the mid-90s, when IUPAC decided that ‘dubnium’ is the element’s official name (Dubnium showing that the element 105 was indeed discovered in Dubna, Russia).

In 1968, a team of Russian scientists at the Dubna facility used neon-22 ions to bombard an element called Americium-243 which produced element 105 – later to be known as dubnium. In the next two years, the Russian science team refined and continued their experiments. At the same time, an American science team lead by Albert Ghiorso (responsible for the discovery of element 106 and many more) synthesised unnilpentium at the University of California in Berkley, through a reaction between Cf-249 and N-15.

The American experiment conducted in California did not confirm or support the data generated by the Russian team sometime earlier. It was possible that the Russian scientists had generated only one of the isotopes of element 105, but not unnilpentium itself.

The naming of element 105 caused a bit of unrest and dispute between scientific societies on either side of the Iron Curtain. As the case was, with many other chemical elements discovered at the time, element 105 was given two distinctly different names. The Russian scientists favoured the name nielsbohrium in honour of the Danish professor and nuclear physicist Niels Bohr. The Americans, however, did not approve and wanted to call element 105 – hahnium in honour of Otto Hahn. Temporary name was: Unnilpentium - Unp

Uses and Effects on Health and the Environment
There are no practical uses, and the element is only used in scientific research and lab settings. Dubnium is not considered a health hazard and has no biological role.

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