Science Fair Project Encyclopedia
Cleveite
Cleveite is a radioactive mineral containing uranium and found in Norway. It is an impure form of uraninite, and has the composition UO2·UO3·PO·ThO2 with about 10% of the uranium substituted by rare earth elements. It was named after Swedish chemist Per Teodor Cleve.
Cleveite was the first known terrestrial source of helium, which is created by the alpha radiation of the uranium and then lies trapped (occluded) within the mineral. The first sample of helium was obtained by William Ramsay in 1895 when he treated a sample of the mineral with acid. Cleve and Abraham Langlet succeeded in isolating helium from cleveite at about the same time.
Yttrogummite is a variant of cleveite also found in Norway.
10-26-2009 08:16:03
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The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details