Element 110 created by fusing nickel and lead A team of European scientists has added another element to the periodic table with creation of three atoms of element 110 in a nuclear fusion experiment in Darmstadt, Germany. The 12 scientists detected the first atom on Nov. 9 after bombarding a lead target with nickel atoms for two days. Their two-week-long experiment, which ended last week, may also have created a fourth atom of the element. "We detected three atoms for sure, but we are still looking at the tapes/' says Peter Armbruster, head of the nuclear chemistry department at Gesellschaft fur Schwerionenforschung (GSI, Heavy Ion Research Center) in Darmstadt. The discovery team, led by Armbruster, consists of six GSI researchers and six guest scientists. The guests come from the Joint Institute for Nuclear Research, Dubna, Russia; the department of nuclear physics, Comenius University, Bratislava, Slovakia; and the department of physics, University of Jyvaskyla, Finland. The team submitted a paper on the "Production and Decay of 269 110" to Zeitschrift fur Physik A on Nov. 14. Albert Ghiorso of Lawrence Berkeley Laboratory in California, who has been involved in the discovery of 12 previous transuranium elements, calls the GSI work "superb" and "very convincing." "In my mind, there's no doubt at air' that the Darmstadt group has made element 110, he tells C&EN. The GSI researchers identified the new element by examining the a-decay pattern of the atoms. "Since we already know the decay characteristics of element 108 downwards, we can unambiguously assign the a-decay chain of these new atoms to element 110," explains physicist Sigurd Hofmann, a team member. The atoms of the new element have a mass of 269. They were formed by fusion of nickel-62 and lead-208 nuclei, followed by emission of a neutron. The first atom of 110 existed only 393 microseconds before it decayed by emitting a succession of a-particles (helium-4 nuclei): 26911Q ^
2651Q8 ^
261106 ^
257^
"We can follow the a-decay chain
right down to nobelium" (element 102), Hofmann notes. The team used a heavy-ion accelerator known as UNILAC to generate a high-energy beam of nickel-62 atoms. They directed these projectiles at eight lead-208 targets mounted on the circumference of a wheel rotating at 1,125 rpm. The rotations kept the temperature of the lead targets below lead's melting point during the two-week experiment. On average, some 3 trillion particles per second struck each target. "Most of the projectiles go through the target without reaction," Hofmann says. "The fusion of a particle with a lead atom to form an atom of the new element is an extremely rare event." Atoms of the new element have a lower velocity than the projectiles. They were separated from the projectiles by an electromagnetic velocity filter known as SHIP (separator for heavy-ion reaction products). "The separator completely separates 3 x 1012 projectiles per second so you don't see them on the detector," explains Hofmann, who leads the SHIP group. Each atom of element 110 was implanted for a split second in a sophisticated detector system containing an array of position-sensitive silicon diodes. "We can look at the event for about two minutes before we lose it," Armbruster says. "We detect the a-particles as the atoms decay." In 1991, Berkeley's Ghiorso and coworkers, using a different approach, obtained limited evidence that they had made a different isotope of element 110—one with a mass of 267. But "our evidence is not nearly as strong as the Germans'," Ghiorso says. He expresses confidence that an ongoing collaboration to make element 110 between Dubna and California's Lawrence Livermore National Laboratory will soon lead to an even heavier isotope of 110 than the Germans report. Scientists have long been trying to make such neutron-rich "superheavy" nuclei because they are expected to show significantly longer half-lives than the heaviest elements known today. The Darmstadt researchers also are pursuing heavier isotopes. They plan to bombard lead-208 with a beam of nickel-64 nuclei. "We want to produce the isotope of element 110 with atomic mass 271," Hofmann explains. "We predict that both the half-life of this isotope
and the probability of the reaction occurring will increase." The Darmstadt team's long-term aim is to make even heavier elements. "We are confident we can make element 111 and even, one day, element 112," says Armbruster. Michael Freemantle
ACS presidential race won by Ronald Breslow In a very tight race, American Chemical Society members have elected Ronald C. Breslow as 1995 president-elect. Breslow, who is Mitchill Professor of Chemistry at Columbia University, New York City, will serve as president in 1996 and as a member of the ACS Board of Directors from 1995 to 1997. Breslow won by 1,048 votes out of 30,638 valid ballots cast, defeating Allen J. Bard, Hackerman/Welch Regents Professor of Chemistry at the University of Texas, Austin. Mail ballots counted at ACS headquarters in Washington, D.C., gave Breslow 15,843 votes and Bard 14,795. Breslow, 63, has been at Columbia since 1967 and has held the additional title of University Professor for the past two years. He has chaired the Division of Chemistry at the National Academy of Sciences and led the Chemistry Section at the American Association for the Advancement of Science. He currently serves on the ACS Joint Board-
Ronald C. Breslow NOVEMBER 28,1994 C&EN 5
NEWS OF THE
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Council Committee on Chemistry & Public Affairs. In his official statement as a candidate, Breslow stressed his "record of activist leadership roles in other scientific organizations and a long-standing commitment to fighting for a proper recognition of the importance of chemistry and the contributions of chemists.,, Challengers bidding to unseat longterm incumbents made an almost clean sweep in election of four other directors to three-year terms on the ACS Board—two regional directors and two directors-at-large. In Region V, consisting mainly of the midwestern states, Charles B. Lindahl defeated two-term incumbent John G. Verkade, 2,423 to 2,174. Lindahl is general manager and technical director of Ozark-Mahoning Co., a unit of Elf Atochem North America in Tulsa. Verkade is professor of chemistry at Iowa State University, Ames. In races for directors-at-large—who are elected by voting members of the ACS Council—Hank Whalen and Joan E. Shields unseated incumbents Gordon L. Nelson and C. Marvin Lang. Whalen received 248 votes; Shields, 190; Nelson, 160; and Lang, 128. Whalen is vice president and director of corporate development for PQ Corp. in Valley Forge, Pa. Shields is professor and chairman of the department of chemistry at Long Island University's C. W. Post campus, Brookville, N.Y.
ACS voting breakdown Votes
PRESIDENT-ELECT Ronald C. Breslow Allen J. Bard
15,843 14,795
REGION 1 DIRECTOR James G. Bennett Jr. Michael E. Strem
2,151 1,830
REGION V DIRECTOR Charles B. Lindahl John G. Verkade
2,423 2,174
DIRECTORS-AT-LARGEa Hank Whalen Joan E. Shields Gordon L. Nelson C. Marvin Lang
248 190 160 128
Note: In election for president-elect, a total of 30,638 valid ballots were cast, and 823 ballots were declared invalid, a Elected by vote of councilors.
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NOVEMBER 28, 1994 C&EN
Nelson, who is dean of the College of Science & Liberal Arts at Florida Institute of Technology, Melbourne, has had a distinguished ACS career, including service as ACS president in 1988 and a term as director-at-large. Lang, who is professor of chemistry at the University of Wisconsin, Stevens Point, has served two of the allowable three terms as ACS director-at-large. Only in one contest was a board incumbent successful. In the election for director from Region I—the northeastern states—James G. Bennett Jr. survived a challenge by Michael E. Strem, 2,151 to 1,830. Bennett is a principal scientist for General Electric Co. in Selkirk, N.Y., and has served one term as ACS director. Strem is president of Strem Chemicals in Newburyport, Mass. ACS members also overwhelmingly ratified—28,800 to 728—an amendment to the ACS constitution, Article X, Section 6, adopted by the council in August. The amendment distinguishes between the terms candidate and nominee throughout the governing documents and clarifies election procedures. Ernest Carpenter
Union warns OxyChem of environmental suit The Oil, Chemical & Atomic Workers International Union (OCAW) is threatening to sue Occidental Chemical (OxyChem) for environmental violations at its closed 138 million-lb-per-year chloromethane plant in Belle, W.Va., and is trying to use the suit as a lever to get the plant reopened. OCAW special projects director Richard Leonard says it is a 'long shot/7 but the union hopes OxyChem will decide to clean up and run the Kanawha Valley plant—which discontinued production in October—rather than pay millions of dollars in fines for which it could be liable. The shutdown will result in loss of work on Dec. 6 for 49 recently unionized employees and 22 salaried employees. And 12 contract workers also have lost their jobs. OCAW has asked the Environmental Protection Agency and West Virginia authorities to investigate its charges of violations of the Resource Conservation & Recovery Act and the Clean Air Act at the plant. If these agencies do not act
within 60 days (by Jan. 16), OCAW notes, the union can sue OxyChem for the alleged violations. An OxyChem spokesman says the threatened suit 'looks like environmental blackmail. ... The union would never have brought these allegations if we hadn't decided to close the plant/' The charges are "based on inaccurate, incomplete, or outdated information/7 He says the company decided to shut down the 25-acre plant, built in 1920, because it has been unprofitable or marginally profitable, over the past few years. Also, chlorinated chemicals made at the plant—such as chloroform and carbon tetrachloride—face governmentmandated phaseouts or restrictions. Leonard contends OxyChem shut the plant not because it was unprofitable but because the company is antiunion and was angered by the workers' "environmental activism." The union charges that OxyChem vented excessive volatile organic compounds and toxic air pollutants into the air, failed to protect workers against asbestos exposure, and began building a storm water treatment plant without proper permits. These and other violations, OCAW claims, unnecessarily exposed workers and the community to health-threatening compounds. It all comes down to "lousy housekeeping and years of ignoring the law," Leonard says. But the violations would not prevent plant operation once cleanup is complete, he stresses. OxyChem has "no objection to an EPA or state investigation of our environmental practices," the spokesman says. But "there are no reasons why we would restart the plant. . . . We will not change our minds." Marc Reisch
Diradicals captured in femtosecond studies Chemists have carried out direct studies of diradicals—molecules thought to be important intermediates in many classes of reactions—by using femtosecond laser techniques with mass spectrometry. The experiments "freeze" the transient diradicals in time and in the course of a reaction to provide information on what, if any, role they play in various reactions. The research, reported last week in
