Palladium (IPA: /pəˈleɪdiəm/) is a chemical element with symbol Pd and atomic number 46. It is a rare silver white transition metal of the platinum group, resembling platinum chemically. It was discovered in platinum ores in 1803, and named after the asteroid Pallas by William Hyde Wollaston.
Palladium is usually found as a free metal, alloyed with others in the platinum group. It is commercially extracted from copper-nickel ores. Palladium has a great affinity for hydrogen, being able to absorb 900 times its own volume of the gas. Palladium metal and its complexes are often used in catalysis such as in catalytic converters on cars, palladium on carbon used in organic chemistry, and other coupling reactions. As a precious metal, it is sometimes used in jewelry, and has the ISO currency code of XPD. Palladium as an investment has attracted recent investment interests. In early 2007, several ETFs backed by physical palladium were launched, including London ETF Security and ZKB Palladium ETF.