Symbol Ir Atomic radius: pm 136 Fusion: kJ/Mole 41.12
Name Iridium Ionic radius: pm (+4)63 Boiling point: C 4428
Atomic number 77 Electron affinity 1.57 Melting point: C 2446
Atomic weight 192.2 1st  ion potential 9.1 Specific Heat Cap: J/(g K) 0.13
Classification Trans metal Natural form Solid Thermal Cond: W/(cm K) 1.47
Configuration [Xe]4f145d76s2 Crystal structure FCC Electrical Cond 0.197
Oxidation states 2,3,4,6 Density 22.5 Abundance: mg/kg-crust 0.001
Electronegativity 2.2 Vaporization: kJ/Mole 563.6    
Iridium was discovered in 1804 in the acid-insoluble residues of platinum ores by the English chemist, Smithson Tennant. Uses - sparkplugs, crucibles, hardening agent for platinum