铷 (ruthenium) is a chemical element with the symbol Ru and atomic number 44. It is a rare transition metal that belongs to the platinum group and is known for its hardness and resistance to corrosion. Ruthenium is often used in electronics, as well as in the production of certain alloys and catalysts. This element is typically found in ores alongside other platinum group metals. It has several isotopes, with Ru-102 being the most stable. Ruthenium compounds can exhibit various oxidation states, making them useful in various chemical reactions and applications in the field of catalysis.