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 osmium (Os) Bead of high-purity arc-melted osmium. Image copyright: smart-elements.com A hard, silver-gray element in the platinum group; a transition element. Discovered by Smithson Tennant in London in 1803, osmium is the densest of the elements (twice as heavy as lead) and as rare as gold; the chief source is a by-product of smelting nickel. It is slowly oxidized in air. The most common isotope is 192Os (41.0%). Like iridium, osmium is used in producing hard alloys. It is also used to make electrical contacts and pen points. atomic number 76 relative atomic mass 190.2 relative density 22.57 melting point 3.045°C (5,513°F) boiling point 5,027°C (9,081°F) Related categories    • ATOMIC AND NUCLEAR PHYSICS    • INORGANIC CHEMISTRY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP