Palladium is a chemical element wi the chemical seembol Pd an an atomic nummer o 46. It is a rare an lustrous sillery-white metal discovered in 1803 bi William Hyde Wollaston. He named it efter the asteroid Pallas, that wis itsel named efter the epithet o the Greek goddess Athena, acquired bi her whan she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium an osmium fairm a group o elements referred tae as the platinum group metals (PGMs). Thae hae seemilar chemical properties, but palladium haes the lawest meltin pynt an is the least dense o thaim.