Thorium is a moderately soft, paramagnetic, bright silvery radioactive actinide metal that can be bent or shaped. In the See more

A thorium atom has 90 electrons, of which four are valence electrons. Four atomic orbitals are theoretically available for the valence electrons to … See more

Formation
Th is a primordial nuclide, having existed in its current form for over ten billion years; it was formed during the r-process, which probably occurs in See more

The low demand makes working mines for extraction of thorium alone not profitable, and it is almost always extracted with the rare earths, which themselves may be by-products of … See more

There are seven naturally occurring isotopes of Thorium but none are stable. Th is one of the two nuclides beyond bismuth (the other being U) that have half-lives measured in billions of years; its half-life is 14.05 billion years, about three times the See more

Erroneous report
In 1815, the Swedish chemist Jöns Jacob Berzelius analysed an unusual sample of gadolinite from a copper mine in Falun, central Sweden. He … See more

Non-radioactivity-related uses of thorium have been in decline since the 1950s due to environmental concerns largely stemming from the radioactivity of thorium and its decay products. See more