palladium — Palladium (pronounced /p??le?di?m/) 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 in chemical structure. 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.

References: Wikipedia, the free encyclopedia – http://en.wikipedia.org/wiki/Palladium