Ruthenium was discovered in 1844 by the chemist Karl Ernst Claus, working at the University of Kazan, who isolated it from the residues of platinum ore from the Ural Mountains. He named it ruthenium, from Ruthenia, the Latin name for Russia and the Rus lands. It is a hard, brittle, silvery-white member of the platinum group, used to harden platinum and palladium alloys and in electrical contacts and catalysts. Ruthenium stiffens platinum and palladium for jewellery and electrical contacts, features in the resistors of microelectronics and in computer hard-disk coatings, and serves as a versatile catalyst in chemical synthesis. Claus, uncertain whether his find would be accepted, sent samples to the era's most authoritative chemist, Berzelius in Stockholm, whose confirmation was decisive in securing ruthenium's recognition as a genuine new element rather than an impure mixture of known platinum metals.
In recent decades ruthenium compounds have found a research role well beyond hardening jewellery: ruthenium-based dyes are central to experimental dye-sensitised solar cells, and ruthenium catalysts, including those developed by the chemist Robert Grubbs, enabled the olefin metathesis reactions honoured by the 2005 Nobel Prize in Chemistry.