Nuclear chemistry

Element 112 ununbium similar to mercury

Working with element 112 is not easy - it does not occur in the wild and only a few atoms at a time can be made. In this new paper a large group of Swiss, Russian, and Polish authors report:

"a more reliable chemical characterization of element 112, involving the production of two atoms of 283112 through the alpha decay of the short-lived 287114 (which itself forms in the nuclear fusion reaction of 48Ca with 242Pu) and the adsorption of the two atoms on a gold surface. By directly comparing the adsorption characteristics of 283112 to that of mercury and the noble gas radon, we find that element 112 is very volatile and, unlike radon, reveals a metallic interaction with the gold surface. These adsorption characteristics establish element 112 as a typical element of group 12, and its successful production unambiguously establishes the approach to the island of stability of superheavy elements through 48Ca-induced nuclear fusion reactions with actinides."1

Nuclear Power Expansion in the USA

Dr. Thomas Neff, a research affiliate at the MIT (Massachussetts Institute of Technology) Center for International Studies states that limited supplies of uranium fuel for nuclear power plants may thwart the renewed and growing interest in nuclear energy in the United States and other nations.

Over the past 20 years, safety concerns and politics dampened all aspects of development of nuclear energy. No new reactors were ordered and there was investment neither in new uranium mines nor in building facilities to produce fuel for existing reactors. Instead, the nuclear industry lived off commercial and government inventories which are now nearly gone. It is stated that worldwide uranium production meets only about 65% of current reactor requirements.

A few years ago uranium inventories were being sold at US$ 10 per pound; the current price is US$ 85 per pound.

Much of the uranium used by the United States comes from mines in Australia, Canada, Namibia, and, Kazakhstan. Small amounts are mined in the western United States, but the United States is largely reliant on overseas supplies. The United States also relies for half its fuel on Russia under a “swords to ploughshares” 1991 deal. This deal is converting about 20,000 Russian nuclear weapons to fuel for U.S. nuclear power plants, but it ends in 2013, leaving a substantial supply gap for the United States.

Further, China, India, and even Russia have plans for massive deployments of nuclear power and are trying to lock up supplies from countries on which the United States has traditionally relied. As a result, the United States could be the “last one to buy, and it could pay the highest prices, if it can get uranium at all,” Neff said. “The take-home message is that if we're going to increase use of nuclear power, we need massive new investments in capacity to mine uranium and facilities to process it.”

Mined uranium comes in several forms, or isotopes. For starting a nuclear chain reaction in a reactor, the only important isotope is uranium-235, which accounts for only 7 out of 1000 atoms in the mined product. To fuel a nuclear reactor, the concentration of uranium-235 must be 40 to 50 out of 1000 atoms. This is done by separating isotopes in an enrichment plant to achieve the higher concentration, but there is not enough processing capacity worldwide to enrich all the uranium required.

Welcome back element 118 (ununoctium)

Experiments conducted at the Flerov Laboratory of Nuclear Reactions (Joint Institute for Nuclear Research) at Dubna in Russia indicate that element 118 (ununoctium, Uuo) was produced. Not too much though, one atom in the spring of 2002 and two more in 2005.1,2

The 2002 experiment involved firing a beam of 4820Ca at 24998Cf. The experiment took 4 months and involved a beam of 2.5 x 1019 calcium ions to produce the single event believed to be the synthesis of 294118Uuo.

24998Cf + 4820Ca → 294118Uuo + 31n

This ununoctium isotope loses three alpha particles in rapid succesion:

294118Uuo → 290116Uuh + 42He (1.29 milliseconds)

290116Uuh → 286114Uuq + 42He (14.4 milliseconds)

286114Uuq → 282112Uub + 42He (230 milliseconds)

The 282112Uub species then undergoes spontaneous fragmentation (denoted SF) to other species. It took a few years to carry out enough research to properly characterize the decompoition products.

In 2005 a similar experiment but with more sensitive detectors and a total beam dose of 1.6 x 1019 calcium ions resulted in the detection of two further events arising from the formation of 294118Uuo.

This work is particularly significant given the scandal associated with the first report (now withdrawn) of element 118.

Roentgenium: element 111


IUPAC have made a provisional recommendation about the name for element 111. To quote: "A joint IUPAC-IUPAP Working Party (JWP) has confirmed the discovery of element number 111 and this by the collaboration of Hofmann et al. from the Gesellschaft für Schwerionenforschung mbH (GSI) in Darmstadt, Germany. In accord with IUPAC procedures, the discoverers have proposed a name and symbol for the element. The Inorganic Chemistry Division Committee now recommends this proposal for acceptance. The proposed name is roentgenium with symbol Rg.

This proposal lies within the long established tradition of naming elements to honour famous scientists. Wilhelm Conrad Röntgen discovered X-rays in 1895."

New elements 113 (ununtrium) and 115 (ununpentium)

It is claimed that recent experimental results involving the bomabardment of americium-243 with calcium-48 ions are consistent with the formation in the laboratory of a few atoms of elements 113 and 115. In experiments conducted at the JINR U400 cyclotron with the Dubna gas-filled separator between July 14 and Aug. 10, 2003, atomic decay patterns were observed that are said to confirm the existence of element 115 and element 113. In these decay chains, element 113 is produced via the alpha decay of element 115.1

The news has been picked up in a number of online sources including Nature2 and elsewhere.

Element 110 gets a name!


Provisional Recommendations
Inorganic Chemistry Division

Recommendation for the Naming of Element of Atomic Number 110

Prepared for publication by J. Corish and G. M. Rosenblatt

A joint IUPAC-IUPAP Working Party confirms the discovery of element number 110 and this by the collaboration of Hofmann et al. from the Gesellschaft für Schwerionenforschung mbH (GSI) in Darmstadt, Germany.

In accord with IUPAC procedures, the discoverers have proposed a name and symbol for the element. The Inorganic Chemistry Division Committee now recommends this proposal for acceptance. The proposed name is darmstadtium with symbol Ds. This proposal lies within the long established tradition of naming an element after the place of its discovery.

Element 118 discovery retracted

The team of Berkeley Lab scientists that announced two years ago (1999) the observation of what appeared to be Element 118 (heaviest undiscovered transuranic element at the time) has retracted its original paper after several confirmation experiments failed to reproduce the results. This means that the pages for element 118 and parts of the data for element 116 are wrong.

WebElements: the periodic table on the WWW [http://www.webelements.com/]

Copyright 1993-2011 Mark Winter [The University of Sheffield and WebElements Ltd, UK]. All rights reserved.