Cerium: The Most Abundant Rare Earth Element?

Though considered “rare” in name only but does cerium qualify as the most abundant rare earth element?

By: Ringo Bones

It is considered rare in name only given that cerium occurs in the Earth’s crust at a concentration of 44 parts per million. On a percentage basis of abundance in the Earth’s crust – cerium is more plentiful than either tin or lead. And cerium is also found dissolved in seawater at a concentration of 1.8 tons per cubic mile of seawater. By comparison, the rare earth element thulium – the scarcest of the family on a percentage basis in the Earth’s crust – is only slightly rarer than iodine.

Chemical symbol Ce, atomic number 58 and named after the asteroid Ceres, cerium was discovered in 1803 by Jöns Jakob Berzelius and Wilhelm Hisinger of Sweden. It is the chief ingredient – at just under 50 percent – of misch-metal alloy often used in the manufacture of lighter flints. Cerium is used in alloys to make heat-resistant jet engine parts; its oxide has been used as a de rigueur petroleum cracking catalyst since the 1960sand as a volumetric oxidizing agent in most important industrial chemical processes.