INORGANIC CHEMISTRY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site iridium (Ir) High-purity iridium powder. Image copyright: smart-elements.com A very hard and brittle, exceptionally corrosion-resistant, whitish-yellow metallic element. Iridium is a transition element and a member of the platinum group. It occurs in platinum ore and is used principally to harden platinum and in high-temperature materials, electrical contacts, and wear-resistant bearings. It is also used to encapsulate radioactive fuels on spacecraft. Discovered by Smithson Tennant in London in 1803, its name comes from the Latin iris (stem irid-) for "rainbow," from the variety of colors in gives in solution. atomic number 77 relative atomic mass 192.2 relative density 22.42 (at 17°C) melting point 2,140°C boiling point 4,527°C Related category    • INORGANIC CHEMISTRY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP