77 - Iridium transition metal
Discovered by Smithson Tennant in 1804
- Atomic Radius (Å)
Iridium is a chemical element with symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, iridium is generally credited with being the second densest element (after osmium) based on measured density, although calculations involving the space lattices of the elements show that iridium is denser. It is also the most corrosion-resistant metal, even at temperatures as high as 2000 °C. Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.
Shell | Electrons | Orbitals |
---|---|---|
1 | 2 | 2 in 1s |
2 | 8 | 2 in 2s + 6 in 2p |
3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
4 | 32 | 2 in 4s + 6 in 4p + 10 in 4d + 14 in 4f |
5 | 15 | 2 in 5s + 6 in 5p + 7 in 5d |
6 | 2 | 2 in 6s |
192.22 u
Atomic Mass
1.9 Å
Atomic Radius
4701 K
Boiling Point
1.41 Å
Covalent Radius
22.56 g/cm³
Density
150.94
Electron Affinity
2.2
Electronegativity
8.97 eV
First Ionization Energy
2716.15 K
Melting Point
6
Number of Shells
77
Atomic Number
2, 8, 18, 32, 15, 2
Electron Shell Occupations