不過科學技術發展飛速。參閱/上的報道：
科學家首次合成第117號元素 將填補已發現的第116號和118號元素之間缺失的“壹環”
俄美科學家成功合成了壹種擁有117個質子的新元素，它可能就是科學家壹直尋找的第117號元素(ununseptium)，這將填補目前已被發現的第116號和118號元素之間缺失的“壹環”。相關研究論文將在近期出版的《物理評論快報》（Physical Review Letters）上刊發。
以俄羅斯杜布納聯合核研究所尤裏·奧加涅相為學術帶頭人的國際科研小組，使用該研究所的粒子回旋加速器，用由20個質子和28個中子組成的鈣48原子，轟擊含有97個質子和152個中子的錇249原子，生成了6個擁有117個質子的新原子，其中的5個原子有176個中子，另壹個原子有177個中子。
杜布納聯合核研究所於2000年和2006年分別合成了第116號和迄今為止最重的第118號元素。第117號新元素成功合成後，從第112號至118號元素7種相鄰新元素的產生都出自同門，這不能不說是人類科技史上壹大奇觀。
該項科研成果也支持了理論界長期以來的假設：新合成的元素會越來越重，它們最終會變得更加穩定，其壽命也比迄今為止的人造元素更長，這將證實“穩定島”的存在。第117號新元素的相關實驗證實了這壹觀點。奧加涅相小組對新元素進行放射性衰變分析後認為：“為預測超重元素‘穩定島’的存在提供了實驗證據。”
20世紀60年代，科學家提出了“穩定島”理論。該理論認為，在質子數為114、中子數為184的區域附近存在壹些衰變相對穩定的元素，這就是超重元素穩定島。在這個“穩定島”內的超重元素是相當穩定的，它們的半衰期甚至可能達到1015年。但到目前為止所生成的超重元素及其同位素的壽命都很短，大多在秒和毫秒的量級。
據悉，該研究的各項工作分別在俄羅斯杜布納聯合核研究所、美國加州勞倫斯利弗莫爾國家實驗室、美國橡樹嶺國家實驗室、範德堡大學、內華達大學完成。
1869年問世的門捷列夫元素周期表是宇宙的基本規律之壹，也為人類認識自然提供了壹把刻度精準的尺子。緊握這把尺子，核物理學家於上世紀60年代提出了“穩定島”理論。迄今為止，人類能夠合成重元素，但卻始終沒有登上“穩定島”。而“島”上的無限風光正是科學的無限魅力，她將刷新人類物理學、化學、天體演化乃至宇宙觀的所有基本“頁面”。成功地合成117號元素，也許能夠成為通往“穩定島”的壹座航標。
from 科學網
New York Times:
A team of Russian and American scientists has discovered a new element that has long stood as a missing link among the heaviest bits of atomic matter ever produced. The element, still nameless, appears to point the way toward a brew of still more massive elements with chemical properties no one can predict.
Get Science News From The New York Times ? The team produced six atoms of the element by smashing together isotopes of calcium and a radioactive element called berkelium in a particle accelerator about 75 miles north of Moscow on the Volga River, according to a paper that has been accepted for publication at the journal Physical Review Letters.
Data collected by the team seem to support what theorists have long suspected: that as newly created elements become heavier and heavier they will eventually become much more stable and longer-lived than the fleeting bits of artificially produced matter seen so far.
If the trend continues toward a theorized “island of stability” at higher masses, said Dawn A. Shaughnessy, a chemist at Lawrence Livermore National Laboratory in California who is on the team, the work could generate an array of strange new materials with as yet unimagined scientific and practical uses.
By scientific custom, if the latest discovery is confirmed elsewhere, the element will receive an official name and take its place in the periodic table of the elements, the checkerboard that begins with hydrogen, helium and lithium and hangs on the walls of science classrooms and research labs the world over.
“For a chemist, it’s so fundamentally cool” to fill a square in that table, said Dr. Shaughnessy, who was much less forthcoming about what the element might eventually be called. A name based on a laboratory or someone involved in the find is considered one of the highest honors in science. Berkelium, for example, was first synthesized at the University of California, Berkeley.
“We’ve never discussed names because it’s sort of like bad karma,” she said. “It’s like talking about a no-hitter during the no-hitter. We’ve never spoken of it aloud.”
Other researchers were equally circumspect, even when invited to suggest a whimsical temporary moniker for the element. “Naming elements is a serious question, in fact,” said Yuri Oganessian, a nuclear physicist at the Joint Institute for Nuclear Research in Dubna, Russia, and the lead author on the paper. “This takes years.”
Various aspects of the work were done at the particle accelerator in Dubna; the Livermore lab; Oak Ridge National Laboratory and Vanderbilt University in Tennessee; the University of Nevada, Las Vegas; and the Research Institute of Atomic Reactors in Dimitrovgrad, Russia.
For the moment, the discovery will be known as ununseptium, a very unwhimsical Latinate placeholder that refers to the element’s atomic number, 117.
“I think they have an excellent convincing case for the first observation of element 117; most everything has fallen into line very well,” said Walter D. Loveland, a professor of chemistry at Oregon State University who was not involved in the work.
Elements are assigned an atomic number according to the number of protons — comparatively heavy particles with a positive electric charge — in their nuclei. Hydrogen has one proton, helium has two, and uranium has 92, the most in any atom known to occur naturally. Various numbers of charge-free neutrons add to the nuclear mass of atoms but do not affect the atomic number.
As researchers have artificially created heavier and heavier elements, those elements have had briefer and briefer lifetimes — the time it takes for unstable elements to decay by processes like spontaneous fission of the nucleus. Then, as the elements got still heavier, the lifetimes started climbing again, said Joseph Hamilton, a physicist at Vanderbilt who is on the team.
The reason may be that the elements are approaching a theorized “island of stability” at still higher masses, where the lifetimes could go from fractions of a second to days or even years, Dr. Hamilton said.
In recent years, scientists have created several new elements at the Dubna accelerator, called a cyclotron, by smacking calcium into targets containing heavier radioactive elements that are rich in neutrons — a technique developed by Dr. Oganessian.
Because calcium contains 20 protons, simple math indicates scientists would have to fire the calcium at something with 97 protons — berkelium — to produce ununseptium, element 117.
Berkelium is mighty hard to come by, but a research nuclear reactor at Oak Ridge produced about 20 milligrams of highly purified berkelium and sent it to Russia, where the substance was bombarded for five months late last year and early this year.
An analysis of decay products from the accelerator indicated that the team had produced a scant six atoms of ununseptium. But that was enough to title the paper, “Synthesis of a new element with atomic number Z=117.”
That is about the closest thing to “Eureka!” that the dry conventions of scientific publication will allow. The new atoms and their decay products displayed the trend toward longer lifetimes seen in past discoveries of such heavy elements. The largest atomic number so far created is 118, also at the Dubna accelerator.
Five of the six new atoms contained 176 neutrons to go with their 117 protons, while one atom contained 177 neutrons, said Jim Roberto, a physicist at Oak Ridge on the project.
Atomic nuclei can be thought of as concentric shells of protons and neutrons. The most stable nuclei occur when the outermost shells are filled. Some theories predict this will happen with 184 neutrons and either 120 or 126 protons: the presumed center of the island of stability.
What happens beyond that point is anyone’s guess, said Kenton Moody, a radiochemist on the team at Livermore. “The question we’re trying to answer is, ‘Does the periodic table come to an end, and if so, where does it end?’ ” Dr. Moody said.
By JAMES GLANZ