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| Atomic Number: | 46 | Atomic Symbol: | Pd | | Atomic Weight: | 106.4 | Electron Configuration: | 2-8-18-18-0 | | Shells: | 2,8,18,18,0 | Filling Orbital: | 4d10 | | Melting Point: | 1552oC | Boiling Point: | 2927oC | | Description: | Soft white transition metal | | Uses: | For dental crowns and also to make jewelry and surgical
instruments. |
HistoryPalladium was named after the asteroid Pallas, which was
discovered at about the same time. Pallas was the Greek goddess of wisdom.
SourcesDiscovered in 1803 by Wollaston, Palladium is found with
platinum and other metals of the platinum group in placer deposits of Russia,
South America, North America, Ethiopia, and Australia. It is also found
associated with the nickel-copper deposits of South Africa and Ontario.
Palladium's separation from the platinum metals depends upon the type of ore in
which it is found.
PropertiesThe element is a steel-white metal, it does not tarnish in
air, and it is the least dense and lowest melting of the platinum group of
metals. When annealed, it is soft and ductile; cold-working greatly increases
its strength and hardness. Palladium is attacked by nitric and sulfuric acid.
At room temperatures, the metal has the unusual property of absorbing up to
900 times its own volume of hydrogen, possibly forming Pd2H.
It is not yet clear if this is a true compound. Hydrogen readily diffuses
through heated palladium, providing a means of purifying the gas.
UsesFinely divided palladium is a good catalyst and is used for
hydrogentation and dehydrogenation reactions. It is alloyed and used in jewelry
trades.
White gold is an alloy of gold decolorized by the addition of palladium. Like
gold, palladium can be beaten into leaf as thin as 1/250,000 in. The metal is
used in dentistry, watchmaking, and in making surgical instruments and
electrical contacts.
CostThe metal sells for about $150/troy oz.
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