Palladium is another chemical element with the chemical symbol Pd, and atomic number 46. Like platinum, it has a white-silver color and is a very rare metal. It was discovered in 1803 by William Hyde Wollaston. The metal is named after the asteroid Pallas. Palladium belongs to a group of elements called the platinum group. This group includes platinum, rhodium, ruthenium, iridium, and osmium.
Palladium is the least dense and melts at the lowest temperature of all of these metals. About half of the supply of platinum is used for catalytic converters. These are used to convert toxic gases from auto exhaust to substances that are less harmful. It is also used in the production of electronics, in dental equipment, medicine, chemical applications, groundwater treatment and jewelry. Palladium is important in the technology that is used for fuel cells, which create electricity, heat and water by combining hydrogen and oxygen.
Most of the deposits of palladium are found in South Africa, Montana, Ontario, and in Russia. It is also extracted from thrown away catalytic converters. It has a lot of investment interest because it is used in various applications, but has a limited supply.
Palladium resembles platinum in that they have the same color and luster. However, it is not as resistant durable and platinum. When annealed, it becomes soft and docile, but when cold, it has a much higher strength and hardness. It also dissolves slowly in sulfuric, nitric, and hydrochloric acid. It does not tarnish when exposed to air because it does not react to oxygen at normal temperatures. It will tarnish in a moist atmosphere that contains sulfur. Platinum has seven isotopes, which include six table isotopes.
Russia was the top producer of palladium in the year 2007, with a 44% share. Other countries that followed include South Africa, Canada, and the US, which are the only significant producers of palladium. It is found alloyed with gold and other platinum group metals in various deposits in places like Australia, Ethiopia, and North and South America. However, these deposits have a very minor role in the production of palladium. Commercially, the most important deposits are found in Ontario and Siberia.
Palladium can also be extracted from spent nuclear fuel in nuclear fission reactors, but that palladium is not used. There is no equipment to extract palladium from radioactive waste yet. Palladium is used in a variety of applications. It is used in catalysis, where it is used to speed up hydrogenation and de-hydrogenation reactions. It is used in electronics as well, in multilayer ceramic capacitors. It is also used often in jewelry. Palladium is used in developing photographs as well.