16 November 2009
Thorium, element 90, was discovered by Swedish chemist Jöns Jakob Berzelius in 1828. Berzelius named the metal after Thor, the Norse god of thunder. The chemical symbol for thorium is Th.
But this wasn’t the first time that Berzelius named a substance for the god. In 1815 he called a compound, which turned out to be yttrium phosphate, thorjord, or Thor’s earth. The French flubbed the Swedish name, dubbing the compound thorine in their language, from which English took the name thorina (which is no longer in use.)
To further confuse matters, for a time British chemists gave the name thorinum to the hypothetical element of which Berzelius’s thorjord was the oxide. And following Berzelius’s 1828 discovery of the real element thorium, some French and British took to calling that thorinum too. Fortunately, this state of affairs was confined to the 19th century and the name thorium is the only one still in use. This type of situation is fairly common in scientific nomenclature. With new discoveries, knowledge is very tentative and uncertain, and sometimes a number of terms come into use for a period to denote both real and hypothetical objects and concepts. As knowledge and scientific certainty grows, the nomenclature settles down to generally accepted and long-lasting terms.