Symbol Ir
Atomic Number 77
Atomic Mass 192.217
Discovered by Ghiorso in 1952

Chemical Properties of Iridium

Group 9 Melting point 2446 °C, 4435 °F, 2719 K
Period 6 Boiling point 4428 °C, 8002 °F, 4701 K 
Block d Density (g cm−3) 22.5622 
Atomic number 77 Relative atomic mass 192.217
State at 20°C Solid Key isotopes 193Ir 
Electronic configuration [Xe] 4f145d76s2 

Table of Contents

What is Iridium?

  • Iridium is a transition metal of the platinum family with the symbol Ir and atomic number 77 in the periodic table.
  • Iridium is a hard, lustrous, brittle, dense transition metal of the platinum family.

Physical properties of Iridium

  • It is silverish-white and it is known to be the most corrosion-resistant element known. It is unaffected by air, water, and acids.
  • It is one of the lesser-known members of the platinum group, iridium possesses quite remarkable physical and chemical properties.
  • It is not only the most corrosion-resistant of all metals, but it is insoluble in all mineral acids at high temperatures, also has a very high melting point and is the only metal that can maintain good mechanical properties in air temperatures above 1600 °C.
  • It has a high modulus of rigidity and elasticity.

Applications and effects of Iridium

  • Nowadays the automotive industry, chemical industry and electronic industry have the most demand for iridium, where it is used to coat the electrodes in the Chlor-alkali process, and in catalysts.
  • Some applications are in pivot bearings and in scientific and other special equipment, but it is principally used in alloys: osmium/iridium alloys are used for tipping fountain pen nibs and for compass bearings.
  • It is also known to be used in Space vehicles and Satellites.

Frequently Asked Questions – FAQs


What are the atomic number and atomic symbol for iridium?

The atomic number and atomic symbol for iridium are 77 and Ir.

To which period does iridium belong?

Period 6.

To which group does iridium belong?

Group 9.

Write one use of iridium.

Iridium is used in Space vehicles and Satellites.
Test your Knowledge on Iridium!


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