Iridium is the chemical element with symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element (after osmium) and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C. Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.Symbol: Ir
Electron configuration: Xe 4f14 5d7 6s2
Melting point: 2,447 °C
Atomic number: 77
Discovered: 1804
Atomic mass: 192.217 ± 0.003 u