Palladium

Palladium is a soft, silvery-white metal in the platinum group. William Hyde Wollaston discovered it in 1803 and named it after the asteroid Pallas, found the year before. It is mined mostly in Russia and South Africa, often alongside nickel and platinum.

Most palladium goes into catalytic converters in gasoline cars, which turn toxic carbon monoxide and unburned fuel into less harmful gases. It also plates some connectors and formed the electrodes of older ceramic capacitors, which now mostly use nickel. It goes into dental fillings and jewelry too. Palladium can soak up hundreds of times its own volume of hydrogen gas, which makes it useful for purifying hydrogen.