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Wikipedia:Today's featured article/requests/Thorium

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Thorium

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This is the archived discussion of the TFAR nomination for the article below. Subsequent comments should be made on the appropriate discussion page (such as Wikipedia talk:Today's featured article/requests). Please do not modify this page.

The result was: scheduled for Wikipedia:Today's featured article/March 5, 2018 by Wehwalt (talk) 14:01, 11 February 2018 (UTC)[reply]

A small square of thorium metal in an ampule

Thorium is a weakly radioactive chemical element with symbol Th and atomic number 90. A reactive actinide metal, its chemistry is dominated by the +4 oxidation state. It is silvery and tarnishes black in air, forming the dioxide; it is moderately hard, malleable, and has a high melting point. Its most stable isotope, 232Th, has a half-life of 14.05 billion years, about the age of the universe: it decays very slowly to stable lead. Along with uranium, it is the only primordial significantly radioactive element. Thorium is chiefly refined from monazite sands as a by-product of extracting rare earth metals. It was discovered in 1829 by the Norwegian mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, the Norse god of thunder. It gained applications in the 19th century, but after its radioactivity was discovered in the early 20th century, its use significantly declined. Thorium has been suggested as a replacement for uranium in nuclear reactors. (Full article...)