Palladium, a transition element belonging to group III in the periodic table (nickel group) and light platinum metals, is a medium-hard, moderately forgeable, and ductile silverwhite metal. Soluble in aqua regia, hot nitric acid, sulfuric acid, slightly soluble in hydrochloric acid, insoluble in cold water and hot water
Palladium was discovered in 1803 by W.H. Wollaston during refining and purification of- platinum metal. This new metal was found in the aqua regia extract of native platinum and was detected in solution after platinum was precipitated. It was removed as ammonium chloroplatinate. Treating this solution with mercurous cyanide precipitated a yellow palladium complex salt.Palladium is used mostly in alloys and the majority of its alloys are used for electronics and telecommunications. They are contacts in electrical relays and automatic switching gear. Palladium-gold alloys are applied widely in dentistry and medicine