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Formation of transuranic elements
"All of the elements with higher atomic numbers, however, have been first discovered artificially, and other than plutonium and neptunium, none occur naturally on earth. They are all radioactive, with a half-life much shorter than the age of the Earth, so any atoms of these elements, if they ever were present at the earth's formation, have long since decayed."
Surely this is wrong? For example, if an element has a half life which is a quarter of the age of the earth, one would expect a sixteenth of the original number of atoms to be currently present. I think this needs rewording. [ManInStone]
- The problem is the phrase "shorter than the age of the Earth". That information is a necessary part of the discussion, but is perhaps not the best qualifier for "half-life" given that the half-lives of elements from 100 to 118 range from 101 days to 0.89ms (see ). Calling such short times "much shorter than the age of the Earth" doesn't really provide the reader with the appropriate sense of scale. 18.104.22.168 (talk) 11:24, 25 January 2009 (UTC)
Presumably at least some transuranic elements are formed in supernovae (see for example http://books.google.com/books?id=MfAGpVq8gpQC&pg=PA119&dq=transuranic+elements+supernova). 22.214.171.124 (talk) 03:01, 24 April 2012 (UTC)
Island of stability
Would this need some discussion on the speculative "Island of Stability" of transuranic elements? Even if this was thoroughly discredited it'd be nice for the reader to find out that this was so (I have no clue). -- MartijnFaassen
The assertion that the Dubna results have been discredited is not reflected in the Element naming controversy entry, where it is treated merely as a claim made by one side in the controversy. For consistency, either beef it up there or water it down here :) Joestynes 09:01, 25 Aug 2004 (UTC)
- A group at the Joint Institute for Nuclear Research in Dubna in Russia (then the Soviet Union) who claimed to have produced:
- 104, which they named kurchatovium after the Soviet chemist Igor Kurchatov.
- 105. Although their claim is disputed, the name dubnium is now official for this element, named after the city where they worked. They originally proposed nielsbohrium for this element.
- 106. now known as seaborgium
- 107. bohrium
I removed the above section from the article as I couldnt find any confirmation that these claims had been discredited. RIP-Acer 19:30, 15 May 2007 (UTC)
Def: Super-heavy element?
I think Super-heavy atoms/elements aren't defined to be elements with Z > 104. I think there is no formal definition, but the term SHE/Super-heavy element began to occur in the same context as the island of stability around originally 114 and later around a hypothetical local stability maximum around there. If we hypothetically assume that we ourselves defined a Super-heavy element, it would be in a Z/N diagram where the stability derivative sloope down towards that hypothetical local stability maximum. I think the text shall not define 104 as the defining criterion for a SHE. ... said: Rursus (bork²) 14:40, 22 February 2009 (UTC)
What does "Discovered artificially" really mean? You can produce an element "artificially" in a laboratory, and you can discover something you have produced artficially, if the product was not created consciously and on purpose, but how can you discover artificially anything?
- Poor phrasing. Changed to "discovered in the laboratory", which is also somewhat unclear though, but hopefully the text around that sentence will help. Materialscientist (talk) 10:45, 9 October 2009 (UTC)
Are transuranium elements significant?
I suppose so (since there is a nobel price), but I do not find an application or hint about its significance in this article. —Preceding unsigned comment added by 126.96.36.199 (talk) 13:58, 12 October 2009 (UTC)
- Although a late reply, this still seems a valid concern, as I was myself looking into the possible and existing applications. It seems that at the moment they are practical for current and future research. They can serve to synthesize other elements, for instance. The Einsteinium article discusses it shortly. We probably could borrow some of its text and sources to add an eventual Applications section to this article. 188.8.131.52 (talk) 17:33, 15 December 2015 (UTC)
- Additionally, as per the Island of stability article, a possible application of some of those heavy elements might be compact nuclear weapons: "the quest for fourth generation nuclear weapons". Apparently much of the funding for superheavy element research was for military purposes. 184.108.40.206 (talk) 21:26, 15 December 2015 (UTC)
- And Americium found applications in smoke detectors and spectrometers among others... 220.127.116.11 (talk) 23:20, 15 December 2015 (UTC)
- I finally added a short Application section, borrowing the ideas and references of other above-mentioned articles. 18.104.22.168 (talk) 16:58, 28 August 2016 (UTC)
How much do these cost?
It would interesting to know how much it costs to produce these. Where can we find information on the budgets these researchers have? Shouldn't the Guinness Book of World Records list these as the world's most expensive substances? —Preceding unsigned comment added by 22.214.171.124 (talk) 02:23, 23 October 2009 (UTC)
- It would be a bit strange because these substances are not things you can buy in bulk. It's not like you can waltz into a store of even questionable legality and buy a bar of californium. Nobody has ever made a gram! So the cost looks ridiculous if you scale them up to normal units like grams, but it misses the point: if we could make a gram of californium, it would cost a lot less. The concept of "bulk" buying also gets more and more strained as the critical mass keeps shrinking as we add more protons (did you know that 251Cf has a five-kilogram critical mass?). The only transuraniums that we can currently produce in more-than-gram quantities are the first four: neptunium, plutonium, americium, and curium. It's only for those that you can think of costs. The costs are US$170000/g for Cm, US$1500/g for Am, US$660/g for Np, and US$4000/g for Pu (obtained from Googling). Despite the long half-life of 15.6 million years for 247Cm, it's quite difficult to produce in bulk, and there's also the problem of a seven-kilogram critical mass. Double sharp (talk) 13:40, 30 August 2016 (UTC)