"Dubnium" is a chemical element with symbol "Db" and atomic number 105. It is named after the town of Dubna in Russia , where it was first produced. It is a synthetic element and radioactive; 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 Group 5. 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 to those of other group 5 elements. In the 1960s and 1970s, 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 IUPAC established "dubnium" as the official name for the element. Dubnium was reportedly first discovered in 1968 at the Joint Institute for Nuclear Research at Dubna . Researchers there bombarded an americium-243 target with neon-22 ions. They reported a 9.40 MeV and a 9.70 MeV alpha-activity and assigned the decays to the isotope 260 Db or 261 Db: Two years later the Dubna team separated their reaction products by thermal gradient chromatography after conversion to chlorides by interaction with NbCl 5 . The team identified a 2.2 second spontaneous fission activity contained within a volatile chloride portraying eka-tantalum properties, likely dubnium-261 pentachloride, 261 DbCl 5 . Wiz Science™ is "the" learning channel for children and all ages. SUBSCRIBE TODAY Disclaimer: This video is for your information only. The author or publisher does not guarantee the accuracy of the content presented in this video. USE AT YOUR OWN RISK. Background Music: "The Place Inside" by Silent Partner (royalty-free) from YouTube Audio Library. This video uses material/images from https://en.wikipedia.org/wiki/Dubnium, which is released under Creative Commons Attribution-Share-Alike License 3.0 http://creativecommons.org/licenses/by-sa/3.0/ . This video is licensed under Creative Commons Attribution-Share-Alike License 3.0 http://creativecommons.org/licenses/by-sa/3.0/ . To reuse/adapt the content in your own work, you must comply with the license terms.

• published: 29 Sep 2015
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