Long-lived Super Heavy Element Created

treeves writes "Radioactive nuclei that hang around for a mere half-minute before falling apart hardly seem stable. Yet compared with the fleeting lifetimes of their superheavy atomic neighbors, the roughly 30-second period that transpired from creation to disintegration of four atoms of a newly discovered isotope of element 108 qualifies those atoms as rock solid. Theoretical physicists predicted years ago that some nuclei of elements much more massive than uranium should survive for a relatively long time — possibly long enough to probe their chemical properties — if they could be synthesized. On the chart of nuclides, theoreticians pinpointed a region with coordinates corresponding to 114 protons and 184 neutrons and indicated that nuclei with those "magic" numbers of subatomic particles should lie at the center of an island of stability. The nuclear longevity, according to the models, is due to the closing of proton and neutron shells, which renders the particles stable against spontaneous fission much the same way that a filled outer electron shell endows noble gases with chemical inertness. Experimentalists, though, haven't yet found a route to reach the center of the island."

Rest of article

[richie2000]

Might as well include the rest of the article too:

Other theoreticians calculated the effects of subshell closings in other superheavy nuclei. They concluded that an isotope of hassium containing 108 protons and 162 neutrons (270Hs) should survive a long time--much longer than the millisecond or shorter lifetimes typical of most of the heaviest nuclides.

Now, an international team of experimentalists has detected four of those atoms and probed some of their chemical properties during the roughly 30 seconds the nuclei survive (Phys. Rev. Lett. 2006, 97, 242501). The findings confirm the predictions and provide new statistical data with which such theoretical models can be refined. The team includes 24 scientists from 10 research institutions, including the Technical University of Munich (TUM) and the Institute for Heavy-Ion Research (GSI), both in Germany, as well as institutions in Russia, the U.S., Switzerland, Japan, China, and Poland.

As TUM graduate student Jan Dvorak explains, the hassium nuclei were formed by firing a high-energy beam of 26Mg projectiles into a target enriched in 248Cm. The target was also doped with a small amount of gadolinium to produce isotopes of hassium's lighter homolog, osmium. Upon formation, nuclear products were exposed to a stream of oxygen. From earlier studies of 269Hs, scientists learned that hassium and osmium--but not other heavy elements--form volatile tetroxides, thereby providing a method for filtering unwanted products.

In the latest experiments, the volatile oxides were swept into a multistage chromatographic detector, which was cooled along its length in a gradient from room temperature at one end to -150 C. On the basis of the two sets of experiments, 269Hs and 270Hs exhibit distinct nuclear properties but similar chemical properties, as expected.

The study paints a very consistent picture of that region of the chart of the nuclides and makes clever use of chemistry to sort out an assignment of atomic number, says Kenton J. Moody, a heavy-element research group leader at Lawrence Livermore National Laboratory. Moody adds that the observations support theoretical calculations that scientists have been using to predict transactinide properties and plan superheavy element experiments.

Re:More then just theory...

[calyxa]

I was briefly thrilled the other day about the possibility of counting neutron stars as individual atoms of stable super-heavy elements. I asked my brother, a nuclear physicist, if this was reasonable. he said no, because the neutrons in a neutron star are held together by gravity.

Saving some link-hunting

[TravisW]

Maybe this should have been: "...Island of Stability [wikipedia.org]..." If you're visually inclined, check out the aptly illustrated "chart of nuclides [wikipedia.org]," showing stability as a function of nucleon counts (i.e. proton and neutron counts).

Spiral Periodic Table

[Blighten]

For those of you who aren't theoretical physicists/chemists, another visualization for this Island of Stability is shown in a spiral periodic table [thinkquest.org]. The predicted region of heavy elements that might be stable are labeled superlactindes and come off as a third arm.

Re:Heavy

[khallow]

As I understand it, fusion is necessary to have anything heavier than hydrogen. But you don't get substantial quantities of elements heavier than iron except from supernovas and perhaps some other high energy events (like what a neutron star can do). In particular, as far as we know, everything heavier than iron on Earth either came from one or more supernovas that preceded the existence of Earth or from decay products of those elements. Given the large amount of Uranium 235 and 238 in the Earth's crust, it's likely that all of the heavier elements and isotopes were created in some quantity. So my take is that there's an upper limit to the half life of these elements coming from the fact that we don't obvserve them in nature, but it's a weak limit many orders of magnitude off from what we're seeing in the labs.

Re:Heavy

[CookieOfFortune]

3. The star gets energy out of fusion up to Iron, after that, it loses energy through fusion though it can still occur, creating the heavier elements. I believe they can determine how much longer a star will survive by measuring the iron content, because once it starts producing a lot of iron, it's running out of hydrogen and helium which act as the most efficient fuel. From the article:

the hassium nuclei were formed by firing a high-energy beam of 26Mg projectiles into a target enriched in 248Cm.

I don't think this is considered "fusion" per se because it does not occur spontaneously like in a reactor and probably uses up a lot of energy. I don't think this in itself is a new technique, as that's how they created some of the other heavy elements.

Re:Heavy

[kfg]

So if we can fuse hige Super Heavy atoms together, why can't we fuse lesser atoms together to make, say, gold?

We can. In fact, it was one of the first things we did with our new toys It's a fun game.

It's also very, very expensive.

KFG.

Re:What do they do with these new elements?

[As_I_Please]

These elements aren't useful in the commercial or industrial sense. At the moment, only a handful of atoms can be created at a time.

The creation of these elements is more useful for testing our theories of the structure of the nucleus (finding the Island of Stability [nytimes.com]) and of the periodicity of the chemical elements (if the chemical properties of these rather unnatural elements correspond to their positions on the Periodic Table).

Re:Heavy

[UnxMully]

IANAP (I am not a physicist) but I have studied some astronomy including reactions in stars.

Up to the iron group, fusion reactions are exothermic but produce increasingly less energy, so the higher the mass of the resulting element, the more reactions are needed to produce the energy required to sustain a star.

Reactions beyond the iron group are endothermic so require energy from the star to complete.

The other way elements are produced in stars is the addition of neutrons to already existing atoms, hence increasing their atomic mass and producing a different element. IIRC, the energy required to do this is high and exists only in stars.

There are two types of this reacton, slow and fast. Slow happens in the normal course of events of star evolution where fast happens in the seconds of life during and after a supernova. Elements such as uranium are produced during the fast process. From this, I think these guys have replicated one of the slow/fast addition processes rather than what we tend to call fusion.

As I say, IANAP but that's what I remember.

Re:More then just theory...

[Xolotl]

Not only that, elements are defined by the number of protons, not neutrons.

Re:Saving some link-hunting

[dunelin]

Speaking of another Nova, a recent episode of Nova ScienceNOW on PBS featured Element-114. It was a great feature and even kept my high school chemistry classes in rapt attention for 15 minutes. Quite an accomplishment.

Watch the segment online [pbs.org].

Re:Heavy

[Dragonslicer]

The other way elements are produced in stars is the addition of neutrons to already existing atoms, hence increasing their atomic mass and producing a different element.

Just to clarify that point, adding neutrons to an atom does not directly produce a different element, it produces a different isotope of the same element. Neutrons can, however, be converted into protons, usually by emitting an electron and an antineutrino (I believe neutrons can also be converted to protons by absorbing a positron and a neutrino, but it doesn't happen nearly as frequently).

Re:Reminds me of the book...

[cheesybagel]

Actually, there are small amounts of natural Plutonium [wikipedia.org], due to supernova explosions or natural fission [wikipedia.org] reactors.

I guess the problem is it is pretty hard to find new elements if you do not actually know what you are searching for. Natural Plutonium was only discovered after man-made Plutonium was made in large quantities and well characterized. Heck, Aluminium was only manufactured in quantity in the XIXth century.