Iridium (Ir)
Iridium (Ir)
Iridium was discovered in 1803 and named for its colorful salts.
The most corrosion-resistant metal, it's resistant to acids but altered by hot salts like sodium chloride and sodium cyanide. This element is part of the platinum family and is white with a yellowish cast. It's also hard and brittle and therefore hard to machine, form, or work.
Iridium occurs naturally in alluvial deposits and can be obtained as a by-product of nickel mining.
It's used for crucibles, electrical contacts, and other applications that require high temperature tolerance. Combined with osmium, it's used for pen tips and compass bearings.