Ununtrium

Ununtrium (pronEng|juːˈnʌntriəm or IPA|/əˈnʌntriəm/) is the temporary name of a synthetic element in the periodic table that has the temporary symbol Uut and has the atomic number 113. It has been synthesised both directly in "cold" and "warm" fusion reactions. It was first observed in the decay of ununpentium. Only eight atoms of ununtrium have been observed to date. Following periodic trends it is expected to be a soft, silvery metal.

Discovery Profile

The first report of ununtrium was in August 2003 when it was identified as a decay product of ununpentium. These results were published on February 1, 2004, by a team composed of Russian scientists at Dubna (Joint Institute for Nuclear Research), and American scientists at the Lawrence Livermore National Laboratory. [http://www.jinr.ru/publish/Preprints/2003/178(E7-2003-178).pdf "Experiments on the synthesis of element 115 in the reaction ²⁴³Am(⁴⁸Ca,xn)^291-x115"] , Oganessian et al., "JINR Preprints", 2003. Retrieved on 2008-03-03] [ [http://prola.aps.org/abstract/PRC/v69/i2/e021601 "Experiments on the synthesis of element 115 in the reaction ²⁴³Am(⁴⁸Ca,xn)^291-x115"] , Oganessian et al., "Phys. Rev. C 69", 021601 (2004). Retrieved on 2008-03-03]

:$,^\{48\}\_\{20\}mathrm\{Ca\}\; +\; ,^\{243\}\_\{95\}mathrm\{Am\}\; o\; ,^\{288,287\}mathrm\{Uup\}\; o\; ,^\{284,283\}mathrm\{Uut\}\; o$

On July 23, 2004, a team of Japanese scientists at RIKEN detected a single atom of ²⁷⁸Uut using the cold fusion reaction between Bismuth-209 and zinc-70. They published their results on September 28, 2004. [http://jpsj.ipap.jp/link?JPSJ/73/2593/ "Experiment on the Synthesis of Element 113 in the Reaction ²⁰⁹Bi(⁷⁰Zn, n)²⁷⁸113"] , Morita et al., "J. Phys. Joc. Jpn"., 2004, 73, 10. Retrieved on 2008-03-03]

:$,^\{70\}\_\{30\}mathrm\{Zn\}\; +\; ,^\{209\}\_\{83\}mathrm\{Bi\}\; o\; ,^\{279\}\_\{113\}mathrm\{Uut\}\; ^\{*\}\; o\; ,^\{278\}\_\{113\}mathrm\{Uut\}\; +\; ,^\{1\}\_\{0\}mathrm\{n\}$

Support for their claim appeared in 2004 when scientists at the Institute of Modern Physics (IMP) identified ²⁶⁶Bh as decaying with identical properties to their single event (see bohrium).

The RIKEN team produced a further atom on April 2, 2005, although the decay data was different from the first chain, and may be due to the formation of a meta-stable isomer.

The Dubna-Livermore collaboration has strengthened their claim for the discovery of ununtrium by conducting chemical experiments on the decay daughter ²⁶⁸Db. In experiments in Jun 2004 and Dec 2005, the Dubnium isotope was successfully identified by milking the Db fraction and measuring any SF activities. Both the half-life and decay mode were confirmed for the proposed ²⁶⁸Db which lends support to the assignment of Z=115 and Z=113 to the parent and daughter nuclei. [ [http://www.jinr.ru/publish/Preprints/2004/157(e12-2004-157).pdf "RESULTS OF THE EXPERIMENT ON CHEMICAL IDENTIFICATION OF Db AS A DECAY PRODUCT OF ELEMENT 115"] , Oganessian et al., JINR preprints, 2004. Retrieved on 2008-03-03] [ [http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000072000003034611000001&idtype=cvips&gifs=yes "Synthesis of elements 115 and 113 in the reaction ²⁴³Am + ⁴⁸Ca"] , Oganessian et al., "Phys. Rev. C72", 034611 (2005). Retrieved on 2008-03-03]

Theoretical estimates of alpha-decay half-lives of alpha-decay chains from element 113 are in good agreement with the experimental data.citejournal|journal=Phys. Rev. C|volume=75|pages= 047306|year=2007|title=α decay chains from element 113|author=P. Roy Chowdhury, D. N. Basu and C. Samanta |url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000075000004047306000001&idtype=cvips&gifs=yes|doi=10.1103/PhysRevC.75.047306]

Naming

Current names

The element with Z=113 is historically known as "eka-thallium". "Ununtrium" (Uut) is a temporary IUPAC systematic element name. Research scientists usually refer to the element simply as "element 113" (E113).

Proposed names by claimants

Claims to the discovery of element 113 have been put forward by Dmitriev of the Dubna team and Morita of the RIKEN team. The JWP will decide to whom the right to suggest a name will be given. The IUPAC have the final say on the official adoption of a name.The table below gives the names that the teams above have suggested and which can be verified by press interviews.

Electronic structure

Ununtrium is element 113 in the Periodic Table. The two forms of the projected electronic structure are:

Bohr model: 2, 8, 18, 32, 32, 18, 3

Quantum mechanical model: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f¹⁴5d¹⁰6p⁶7s²5f¹⁴6d¹⁰7p¹

Extrapolated chemical properties of eka-thallium

Oxidation states

Element 113 is projected to be the first member of the 7p series of non-metals and the heaviest member of group 13 (IIIA) in the Periodic Table, below thallium.Each of the members of this group show the group oxidation state of +III. However, thallium has a tendency to form only a stable +I state due to the "inert pair effect", explained by the relativistic stabilisation of the 7s-orbitals, resulting in a higher ionisation potential and weaker tendency to participate in bonding.

Chemistry

Element 113 should portray eka-thallium chemical properties and should therefore from a monoxide, Uut₂O, and monohalides, UutF, UutCl, UUtBr and UutI. If the +III state is accessible, it is likely that it is only possible in the oxide, Uut₂O₃, and fluoride, UutF₃.

History of synthesis of isotopes by cold fusion

=²⁰⁹Bi(⁷⁰Zn,xn)^279-x113 (x=1)=

The synthesis of element 113 was first attempted in 1998 by the team at GSI using the above cold fusion reaction. In two separate runs, they were unable to detect any atoms and calculated a cross section limit of 900 fb. [http://www.gsi.de/informationen/wti/library/scientificreport2003/files/1.pdf "Search for element 113"] , Hofmann et al., "GSI report 2003". Retrieved on 2008-03-03] They repeated the experiment in 2003 and lowered the limit further to 400 fb.In late 2003, the emerging team at RIKEN using their efficient apparatus GARIS attempted the reaction and reached a limit of 140 fb. In December 2003-August 2004, they resulted to 'brute force' and performed an eight-month-long irradiation in which they increased the sensitivity to 51 fb. They were able to detect a single atom of ²⁷⁸113.They repeated the reaction in several runs in 2005 and were able to synthesise a second atom. They calculated a record-low 31 fb for the cross section for the 2 atoms.

History of synthesis of isotopes by hot fusion

=²³⁷Np(⁴⁸Ca,xn)^285-x113 (x=3)=

In June 2006, the Dubna-Livermore team synthesised ununtrium directly in the "warm" fusion reaction between neptunium-237 and calcium-48 nuclei. Two atoms of ²⁸²Uut were detected with a cross section of 900 fb. [http://nrv.jinr.ru/pdf_file/PhysRevC_76_011601.pdf "Synthesis of the isotope ²⁸²113 in the ²³⁷Np+⁴⁸Ca fusion reaction"] , Oganessian et al., "Phys. Rev. C76", 011601(R) (2007). Retrieved on 2008-03-03]

Chronology of isotope discovery

References

ee also

*Isotopes of ununtrium
*Island of stability

External links

* [http://www.webelements.com/webelements/elements/text/Uut/index.html WebElements.com - Uut]
* [http://www.radiochemistry.org/periodictable/elements/115.html Uut and Uup Add Their Atomic Mass to Periodic Table]
* [http://www.apsidium.com/elements/113.htm Apsidium - Ununtrium]
* [http://www-cms.llnl.gov/e113_115/images.html Discovery of Elements 113 and 115]
* [http://physicsweb.org/articles/world/17/7/7 Superheavy elements]