4 entries with one-by-one descriptions.
Iridium, the second densest element, is silvery-white that resembles platinum but with a slightly yellow tint. It is hard and brittle with a high boiling point that makes it difficult to use or work. Iridium is the most corrosion-resistant metal; it has handling temperatures as high as 2,000ºC, but in a powder or dust form it is highly reactive and flammable.
Palladium, like other platinum group metals (PGMs), is a rare, silvery-white metal found in the earth's crust. When annealed, it is a soft, ductile, noble metal that does not tarnish in air below 800ºC. The strength and hardness of palladium can be increased by cold-working. It has the lowest boiling point (2,963ºC) and is the least dense of all PGMs. Palladium has a unique ability to absorb hydrogen at up to 900 times its own volume.
Platinum, one of the rarest elements found in the Earth's crust, has a silvery-white color that never tarnishes. It is a dense, ductile metal that is malleable. Platinum, a noble metal, is corrosion-resistant with high-temperature stability and is non-oxidizable with stable electrical properties. It is part of a group of metals known as the platinum group metals (PGMs).
A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. The physical properties of silver include high ductility, electrical conductivity, malleability, and reflectivity.
Other classes: Compounds · Metals · Non-Metals · Rare Earth Elements · Strategic Elements index