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Good article Thorium has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
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Tens of billions of years[edit]

If the universe is less than 14 billion years old, how can Th and U have been produced tens of billions of years ago?--Klausok (talk) 17:29, 10 July 2016 (UTC)

I messed up; I just meant around ten billion years. Changed. Double sharp (talk) 08:23, 14 July 2016 (UTC)

Early 19th century[edit] this says that the actual thorium mineral was found as early as 1819

This book is rather noted for being so chock-full of errors that I wouldn't trust it; so I would keep the current date. Double sharp (talk) 08:25, 14 July 2016 (UTC) but, according to this, Berzelius got it only in 1928 (believable if we assume they didn't know each other). Also lists uses that were found for Th after 1885

OK, I have this (it's the Wickleder chapter), and while I used it for much of the applications section I can and will write a brief summary up here too. Double sharp (talk) 08:40, 14 July 2016 (UTC) the name dates back to 1817

Added. Double sharp (talk) 08:40, 14 July 2016 (UTC)

These are cool details and I'd love to have them in, but to my dissatisfaction, I can't find out what techniques Berzelius used on a quick look. Apparently I'll have to search for the papers he published.--R8R (talk) 18:29, 12 July 2016 (UTC) -- just take a look. He not only thought there could be a new metal, he though the mineral was an oxide of that metal and he even named the earth as "thorina"; also we learn he experimented with gadolinite when he found it. The source also describes first studies on Th, maybe there's something you find worthy (for example, Berzelius's atomic weight of Th was apparently nowhere near 232 (7.5*16=120), also it was him who started the idea of Th being divalent)

See, this is why this whole thing is murky: there is the xenotime story, that everyone parrots, and then there is also this thing about gadolinite now. I can believe that he thought it was in both minerals, but this is really encroaching on interpreting the sources to one's convenience. (This is where we really need Berzelius' papers.) Double sharp (talk) 08:40, 14 July 2016 (UTC)
Nothing really murky for me, I have a coherent picture of what happened, correct me if I'm missing something: B was studying a gadolinite sample and found a white mineral impurity, which he assumed was an earth of another new element. No source says gadolinite had this thorium on it. That impurity, howe, turned out to be xenotime.--R8R (talk) 08:57, 14 July 2016 (UTC) -- also see this: "In 1815 Berzelius observed thermoluminescence in gadolinite caused by the α-decay of U and Th traces [7]." that [7] actually reveals the original 1815 paper; unfortunately, I can't find it online (also, it's apparently in Swedish, but we could ask a Swede for help if we had the paper to work with; anyway, I got some info already)--R8R (talk) 21:50, 12 July 2016 (UTC)

Not early 19th century, but here's minor detail missing: the German physicist discovered Th's radioactivity before Curie did: "Thorium was discovered to be radioactive by Gerhard Schmidt in 1898 – the first element after uranium to be identified as such. Marie Curie also found this, independently, later in the same year. (3)" --R8R (talk) 21:59, 12 July 2016 (UTC)

Read on Berzelius's analysis techniques here:

I hope these links satiate your need for more info on early 19th century?--R8R (talk) 22:08, 12 July 2016 (UTC)

3 periodic tables[edit]

We don't need three period tables in this article. At the bottom there already was Template:Periodic_table_(32_columns,_compact) but template:PeriodicTable-ImageMap was just added by User:Drbogdan. So one of these two should be cut. Graeme Bartlett (talk) 23:08, 2 December 2016 (UTC)

@Graeme Bartlett: Thank you for your comments - yes - the newly created "{{PeriodicTable-ImageMap}}", an "interactive image map" updated to include the latest officially named elements, was added to the chemical element articles - this version seems to be in the more familiar "Periodic Table" form and, as such, may be more accessible and useful to the average reader - after all => "Readability of Wikipedia Articles" (BEST? => Score of 60/"9th grade/14yo" level)[1] - (also - somewhat related discussions at => "Template talk:Nature timeline#BestWording" and "Template talk:Life timeline#Class Aves as a subset of Dinosaur?") - Comments Welcome from other editors of course - in any case - Enjoy! :) Drbogdan (talk) 00:58, 3 December 2016 (UTC)


  1. ^ Lucassen, Teun; Dijkstra, Roald; Schraagen, Jan Maarten (September 3, 2012). "Readability of Wikipedia". First Monday (journal). 17 (9). Retrieved September 28, 2016.