Ruthenium is a chemical element with the symbol Ru and atomic number 44.

It belongs to the transition metals on the periodic table and is part of the platinum group metals, along with platinum, palladium, rhodium, iridium, and osmium.

At room temperature, ruthenium is a hard, silvery white metal with a high melting point of about 2334 °C (4233 °F).

It is relatively rare in Earth’s crust, which makes it valuable.

Ruthenium was discovered in 1844 by Russian chemist Karl Ernst Claus, who named it after Ruthenia, the Latin name for Russia.

Ruthenium can exist in many oxidation states, ranging from −2 to +8. This wide range makes it highly useful in chemistry.

It is usually resistant to corrosion and does not tarnish easily in air at room temperature.

When strongly oxidized, it can form ruthenium tetroxide (RuO₄), a highly reactive and toxic compound that is structurally similar to osmium tetroxide and is used in staining biological samples.

Ruthenium is commonly used as a catalyst in chemical reactions and plays an important role in hydrogenation reactions in organic chemistry.

Its compounds are used in water splitting and energy research, as well as in electrodes for chlorine production.

When added to alloys, ruthenium improves wear resistance, and even small amounts can significantly harden platinum and palladium.

Ruthenium is used in electrical contacts and chip resistors, and it plays a role in hard disk drives, especially in magnetic layers. Some advanced semiconductors rely on ruthenium based materials.

Ruthenium dioxide (RuO₂) is electrically conductive, which is unusual for an oxide.

Ruthenium is sometimes used to plate jewelry to create a darker gunmetal finish.

It is harder than platinum and increases scratch resistance, while small additions help prevent platinum jewelry from becoming brittle.

Certain ruthenium compounds are studied for anticancer treatments, and some ruthenium based drugs show lower toxicity than traditional platinum drugs.

Ruthenium complexes are also used in photochemistry and light activated research.

Ruthenium is usually found mixed with platinum ores and is often obtained as a byproduct of nickel and platinum mining. Major sources include Russia, South Africa, and Canada.

Ruthenium can form organometallic compounds used in Nobel Prize winning research and helped enable the development of olefin metathesis, a key reaction in modern chemistry.