- Ununseptium
Ununseptium (pronEng|ˌjuːnənˈsɛptiəm or IPA|/ˌʌnənˈsɛptiəm/) is the temporary name of an undiscovered
chemical element in theperiodic table that has the temporary symbol Uus and theatomic number 117. Its half-life presumably will be 3 nanosecondsFact|date=August 2008. It is expected to decay byalpha decay toelement 115 .Future experiments
Ununseptium has not yet been discovered.
As of March 2008 , no attempt to synthesize this element has been reported.Theoretical calculations in a quantum tunneling model with mass estimates from a macroscopic-microscopic model predict the alpha-decay half-lives of isotopes of the element 117 (namely, 289-303117) to be around 0.1-40 ms. citejournal| journal=Nucl. Phys. A|volume=789|pages=142–154|year=2007| title=Predictions of alpha decay half lives of heavy and superheavy elements|author=C. Samanta, P. Roy Chowdhury and D.N. Basu|url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVB-4NF4F0Y-2&_user=2806701&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=3f680654b5659191d67f31681a4cfc83| doi=10.1016/j.nuclphysa.2007.04.001] [citejournal|journal=Phys. Rev. C|volume=77|pages=044603|year=2008|title=Search for long lived heaviest nuclei beyond the valley of stability|author=P. Roy Chowdhury, C. Samanta, and D. N. Basu|url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000077000004044603000001&idtype=cvips&gifs=yes|doi=10.1103/PhysRevC.77.044603] [citejournal|journal=At. Data & Nucl. Data Tables|year=2008|title=Nuclear half-lives for α -radioactivity of elements with 100 < Z < 130 |author=P. Roy Chowdhury, C. Samanta, and D. N. Basu|url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBB-4S26JRX-1&_user=2806701&_coverDate=03%2F14%2F2008&_alid=740505626&_rdoc=6&_fmt=high&_orig=search&_cdi=6706&_sort=d&_docanchor=&view=c&_ct=211&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=dc85a3a8a2ac1faa38c3804f16f86c13]
Chemical properties
Certain chemical properties, such as bond lengths, are predicted to differ from what one would expect based on periodic trends from the lighter
halogen s (because of relativistic effects). [cite web | url=http://dirac.chem.sdu.dk/thesis/96.saue_phd.pdf | title=Principles and Applications of Relativistic Molecular Calculations | author=Trond Saue, page 76] Ununseptium may showsemimetal properties as well.Naming
The name ununseptium is a
systematic element name , used as a placeholder until it is confirmed by other research groups and the IUPAC decides on a name. Usually, the name suggested by the discoverer(s) is chosen.References
External links
* [http://webelements.com/ununseptium/ WebElements.com: Uus]
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