Ruthenium Ru

Discovery

When large deposits of platinum ore were found in Russia's Ural Mountains early in the nineteenth century, several chemists hunted through the residues for new elements. Jędrzej Śniadecki in Poland and Gottfried Osann in Germany each claimed discoveries, but none was confirmed.

In 1844 Karl Ernst Claus at Kazan University painstakingly analysed the residue left after dissolving platinum and proved beyond doubt that a new element was present. He kept the name ruthenium that Osann had proposed earlier.

Ruthenium was the last of the platinum group metals to be discovered. Since the late twentieth century its use in electronics and catalysis has grown considerably.

Origin of the name

The name comes from Ruthenia, a medieval Latin name for the lands of Rus', that is, Russia. Claus worked in Russia and his platinum ore came from the Urals. The symbol is Ru.

Main uses

• Hard disk drives: in the early 2000s, a ruthenium layer only a few atoms thick placed between magnetic layers allowed a big jump in data storage density.
• Electronics: ruthenium dioxide is used in chip resistors, ruthenium plating provides wear-resistant electrical contacts, and ruthenium is being studied as a wiring metal for future chips.
• Alloys: small additions harden platinum and palladium, and some turbine-blade superalloys contain ruthenium.
• Catalysis: ruthenium "Grubbs catalysts" drive olefin metathesis, work recognised by the 2005 Nobel Prize in Chemistry. Ruthenium is also studied for ammonia synthesis and hydrogen production.

Isotopes

Natural ruthenium consists of seven stable isotopes, ruthenium-96, -98, -99, -100, -101, -102 and -104, with ruthenium-102 the most common at about 32%. Radioactive ruthenium-103 (half-life about 39 days) and ruthenium-106 (about one year) are fission products.

In autumn 2017 air-monitoring networks across Europe detected low levels of ruthenium-106. The levels were not a health hazard, but many analyses pointed to a release in the southern Ural region of Russia, which Russian authorities denied.

In everyday life

Ruthenium is recovered as a by-product of platinum and nickel ores, chiefly in South Africa and Russia, and annual production is only tens of tonnes.

The metal itself is unreactive and poses little everyday risk. Ruthenium tetroxide (RuO₄), however, is volatile and highly toxic to the eyes and lungs, so it is handled with great care in laboratories. Ruthenium has also been used in the hard alloy tips of some fountain-pen nibs.