![Ruthenium element card: symbol Ru, atomic number 44, atomic mass 101.07, electron configuration [Kr] 4d⁷ 5s¹, oxidation states +4 +3, Transition metal, group 8, period 5, solid at room temperature.](https://stage.chemistry-dictionary.com/wp-content/uploads/2026/09/ruthenium-chemical-element.webp)
Ruthenium sits in group 8 and period 5 of the periodic table of elements. Miners find it in complex ores with other platinum group metals in the Ural Mountains. It is classified as a classic noble metal because it resists corrosion in moist air.
Ruthenium does not tarnish at normal room temperatures and remains unaffected by most strong acids. This incredible resistance includes boiling aqua regia, which is a very strong acid mixture. However, it can be aggressively attacked by halogens or oxidized by strong alkaline melts.
Halogens are highly reactive nonmetal elements like chlorine, fluorine, and bromine. Ruthenium can exist in several different oxidation states, but +2, +3, and +4 are most common. It forms complex coordination compounds with other molecules to offer rich catalytic properties.
A catalyst is a unique substance that significantly speeds up a chemical reaction. Ruthenium catalysts help drive important olefin metathesis reactions in organic chemistry laboratories. The element is famous for hardening platinum and palladium alloys for industrial use.
An alloy is a solid, durable mixture composed of two or more distinct metals. Adding a microscopic amount of ruthenium greatly improves the corrosion resistance of titanium. Researchers study ruthenium compounds for use in new solar energy conversion technologies. They are also testing these compounds as promising alternatives to platinum-based cancer drugs.