Pages

Thursday, June 23, 2016

Iridium chemical element

Iridium was discovered in 1803 by Smithson Tennant.
The chemical symbol for Iridium is Ir and its atomic number is 77.
We find it listed in the periodic table in Group 9 and 6 period and block d.
The Iridium belongs to the family of transition metals such as for example the Silver, the Bohrium, cadmium, ...
This element is stable.
Iridium as a name came from the latin word iridos which means rainbow.

Iridium chemical element


Atomic number (Z) 77
Group, block group 9, d-block
Period: period 6
Element category: transition metal
Standard atomic weight (±) (Ar) 192.217(3)
Electron configuration [Xe] 4f14 5d7 6s2
per shell: 2, 8, 18, 32, 15, 2

Physical properties
Phase: solid
Melting point: 2719 K ​(2446 °C, ​4435 °F)
Boiling point: 4403 K ​(4130 °C, ​7466 °F)
Density near r.t. : 22.56 g/cm3
when liquid, at m.p. 19 g/cm3
Heat of fusion: 41.12 kJ/mol
Heat of vaporization: 564 kJ/mol
Molar heat capacity: 25.10 J/(mol·K)

Atomic properties
Oxidation states: −3, −1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Electronegativity: Pauling scale: 2.20
Ionization energies 1st: 880 kJ/mol
2nd: 1600 kJ/mol
Atomic radius empirical: 136 pm
Covalent radius: 141±6 pm

Element Crystal structure: face-centered cubic
Speed of sound thin rod: 4825 m/s (at 20 °C)
Thermal expansion: 6.4 µm/(m·K)
Thermal conductivity: 147 W/(m·K)
Electrical resistivity: 47.1 nΩ·m (at 20 °C)
Magnetic ordering: paramagnetic
Young's modulus: 528 GPa
Shear modulus : 210 GPa
Bulk modulus: 320 GPa
Poisson ratio: 0.26
Mohs hardness: 6.5
Vickers hardness: 1760–2200 MPa
Brinell hardness: 1670 MPa
CAS Number: 7439-88-5