Palladium

Palladium is a soft, ductile, steel-white, tarnish-resistant, metallic element occurring naturally with platinum, especially in gold, nickel, and copper ores.  Its atomic number is 46; atomic weight 106.4; melting point 1,552°C; boiling point 3,140°C; specific gravity 12.02 (20°C); valence 2, 3, 4. Along with platinum, rhodium, ruthenium, iridium and osmium, palladium is one of the elements in the "platinum group metals" (PGMs). Palladium has the lowest melting point among this group and is the least dense.

Palladium was discovered in 1803 by William Hyde Wollaston, who named it after the asteroid Pallas, which was discovered about the same time. 

Because it can absorb large amounts of hydrogen, palladium is used as a purification filter for hydrogen and a catalyst in hydrogenation. Over half of the supply of palladium goes into catalytic converters, which convert up to 90% of harmful gases from auto exhaust (hydrocarbons, carbon monoxide and nitrogen oxide) into less harmful substances (nitrogen, carbon dioxide and water vapor). Palladium is used in fuel cells and in many electronics including computers, mobile phones, low voltage electrical contacts, and SED/OLED/LCD televisions. It is alloyed for use in electric contacts, jewelry, nonmagnetic watch parts, and surgical instruments.

Ore deposits of palladium and other platinum group metals are rare, and the most extensive deposits have been found in the norite belt of the Bushveld Igneous Complex in the Transvaal in South Africa, the Stillwater Complex in Montana, United States, the Sudbury District of Ontario, Canada, and the Norilsk Complex in Russia.  Palladium is also obtained by recycling scrapped catalytic converters.

All palladium compounds should be regarded as highly toxic and as carcinogenic. However palladium chloride was formerly prescribed as a treatment for tuberculosis at the rate of 0.065 g per day (approximately 1 mg kg-1) "without too many bad side effects".

Sources:  Answers.com; WebElements.com and Wikipedia.com