Thorium Compounds - History

History

Morten Thrane Esmark found a black mineral on Løvøya island, Norway and gave a sample to his father Jens Esmark, a noted mineralogist. The elder Esmark was not able to identify it and sent a sample to Swedish chemist Jöns Jakob Berzelius for examination in 1828. Berzelius determined that it contained a new element, which he named thorium after Thor, the Norse god of thunder. He published his findings in 1829. Berzelius reused the name of a previous element discovery from a mineral from the Falun which later proved to be a yttrium mineral. The metal had no practical uses until Carl Auer von Welsbach invented the gas mantle in 1885.

Thorium was first observed to be radioactive in 1898, independently, by Polish-French physicist Marie Curie and German chemist Gerhard Carl Schmidt. Between 1900 and 1903, Ernest Rutherford and Frederick Soddy showed how thorium decayed at a fixed rate over time into a series of other elements. This observation led to the identification of half-life as one of the outcomes of the alpha particle experiments that led to their disintegration theory of radioactivity.

The crystal bar process (or "iodide process") was discovered by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925 to produce high-purity metallic thorium.

The name ionium was given early in the study of radioactive elements to the 230Th isotope produced in the decay chain of 238U before it was realized that ionium and thorium were chemically identical. The symbol Io was used for this supposed element.

Thorium-232 is a primordial nuclide, having existed in its current form for over 4.5 billion years, predating the formation of the Earth; it was forged in the cores of dying stars through the r-process and scattered across the galaxy by supernovas. Its radioactive decay produces a significant amount of the Earth's internal heat.

Read more about this topic:  Thorium Compounds

Famous quotes containing the word history:

    What you don’t understand is that it is possible to be an atheist, it is possible not to know if God exists or why He should, and yet to believe that man does not live in a state of nature but in history, and that history as we know it now began with Christ, it was founded by Him on the Gospels.
    Boris Pasternak (1890–1960)

    I believe that in the history of art and of thought there has always been at every living moment of culture a “will to renewal.” This is not the prerogative of the last decade only. All history is nothing but a succession of “crises”Mof rupture, repudiation and resistance.... When there is no “crisis,” there is stagnation, petrification and death. All thought, all art is aggressive.
    Eugène Ionesco (b. 1912)

    There is no example in history of a revolutionary movement involving such gigantic masses being so bloodless.
    Leon Trotsky (1879–1940)