77

Ir

Iridium
192.217 (3)
 Historical Information

Osmium was discovered in 1803 by Smithson Tennant in the dark coloured residue left when crude platinum is dissolved by aqua regia (a mixture of hydrochloric and nitric acid).

Basic Information Shells
  • Name:Iridium
  • Symbol: Ir
  • Atomic number: 77
  • Atomic weight: 192.217 (3)
  • Standard state: solid at 298 K
  • Group in periodic table: 9
  • Group name:Precious metal or Platinum group metal
  • Period in periodic table: 6
  • Block in periodic table: d-block
  • Classification: Metallic
 Iridium
Uses Trivia
  • electrical contacts
  • hardening agent for platinum
  • aking crucibles and apparatus for use at high temperatures

The name iridium is appropriate, for its salts are highly coloured. Iridium is white, similar to platinum, but with a slight yellowish cast. It is very hard and brittle, making it very hard to machine, form, or work.