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Iridium-Discovery, Properties, And Applications

October 15, 2023
written by Qamar Zaman

Iridium is a chemical element with the symbol Ir and atomic number 77. It is a rare, silvery-white, hard, and brittle metal that is very resistant to corrosion. Iridium is a member of the platinum group metals (PGMs) and is found in platinum ores.

image of iridium element
Atomic number77
Relative atomic mass (Ar)192.217
Standard stateSolid at 298 K
AppearanceSilvery white
The group in the periodic table9
Group namePrecious metal or Platinum group metal
Period in periodic table6
Period in the periodic tabled
Shell structure2.
CAS Registry7439-88-5


Iridium was discovered in 1803 by British chemist Smithson Tennant. It was named after the Greek goddess Iris, who was associated with rainbows, because of the wide range of colors its compounds can produce.

Physical Properties

Iridium is a dense, silvery-white metal that is very hard and brittle. It has a melting point of 2,440°C and a boiling point of 4,270°C. Iridium is the most corrosion-resistant metal known and is resistant to attack by acids, bases, and other chemicals.

Chemical Properties

Iridium is a highly unreactive metal and is resistant to corrosion. It forms various compounds with oxygen, sulfur, and halogens. Iridium is also soluble in aqua regia, a highly corrosive mixture of nitric acid and hydrochloric acid.


  • Iridium is one of the rarest elements on Earth and is found in very small quantities in platinum ores.
  • Iridium is used in many industrial applications, including the production of hard-disk coatings, crucibles, and spark plugs.
  • Iridium is also used in medicine as a radioactive tracer in cancer treatment.


Iridium has many important industrial applications due to its unique properties. It is used in the manufacture of hard-disk coatings, crucibles, and spark plugs. Iridium is also used in the production of specialized glass, such as for high-end camera lenses and in the production of high-quality crucibles.

Iridium has also been used in medicine as a radioactive tracer in cancer treatment. This is because iridium-192 is highly radioactive and can be used to target cancer cells in the body.

Iridium is a rare and valuable metal with many unique properties that make it useful in a variety of industrial and medical applications. Its resistance to corrosion and high melting point make it a popular choice for use in high-temperature applications, while its use in medicine demonstrates its versatility and potential for improving human health.