Ir
Iridium · element 77
Transition Metal · Solid at room temperature
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.
Key facts
Atomic mass
192.2173 u
how heavy one atom is
Phase (room temp.)
Solid
Density
22.56 g/cm³
how tightly packed it is
Melting point
2719 K (2446 °C)
when solid turns to liquid
Boiling point
4403 K (4130 °C)
when liquid turns to gas
Period
6
its row in the periodic table
Group
9
its column in the periodic table
Block
D-block
the neighbourhood it lives in
Electronegativity
2.2
how strongly it pulls electrons
Electron configuration
[Xe] 4f14 5d7 6s2
where its electrons live
Shells
2 · 8 · 18 · 32 · 15 · 2
electrons in each layer, inside to out
Discovered by
Smithson Tennant
who found it
Appearance
silvery white
what it looks like
Source: Wikipedia