Appearance and Characteristics
Harmful effects:
Palladium is considered to be of low toxicity.
Characteristics:
Palladium is a rare, lustrous, silvery-white metal.
Palladium is malleable and ductile and like gold, it can be beaten into thin leaf.
It does not tarnish in air but does tarnish lightly in moist air containing sulfur.
The metal is strongly resistant to corrosion in air and to the action of acids (except nitric acid) at ordinary temperatures.
When present in compounds, palladium exists mostly in the oxidation state II.
Palladium is remarkable in its capacity to absorb up to 900 times its own volume of hydrogen. As it absorbs the hydrogen, it expands visibly, like a sponge swelling up when absorbing water.
Uses of Palladium
The largest use of palladium is in catalytic converters for automobiles.
Finely divided palladium is used as a catalyst for hydrogenation/dehydrogenation reactions and for petroleum cracking.
The metal is used in jewelry, for example in white gold (an alloy of gold decolorized by the addition of palladium).
Palladium is used in dentistry, watch making, and in making surgical instruments and electrical contacts.
It is also used to purify hydrogen because the gas easily diffuses through heated palladium.