Discovered by Smithson Tennant in 1803 from a residue of platinum dissolved in aqua regia, its name comes from the Greek for "rainbow" because of the varying color of its salts.
This is the most corrosion-resistant metal, and either it or osmium is the densest known element. Most often used as a hardening agent for platinum, it is part of the alloy from which the standard meter bar is made. Discovered by Smithson Tennant in 1803 from a residue of platinum dissolved in aqua regia, its name comes from the Greek for "rainbow" because of the varying color of its salts. FTP identify this element, number 77, whose concentration in the KT boundary suggests that a large asteroid killed the dinosaurs.
This is the most corrosion-resistant metal, and either it or osmium is the densest known element.
{Iridium}.