Discovered By: Smithson Tennant, William Hyde Wollaston
Discovery year: 1803

The following table showing some properties of Osmium(Os):

Table Example
Atomic number 76
Group 8
Period 6
Block d
Electrons 76
Protons 76
Neutrons 114
Atomic weight 190.23
Oxidation states -2, +2, +3, +4, +6, +8
Ionic charge Os^4+


Table Example
Electrons per shell K2 L8 M18 N32 O14 P2
Electron configuration 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2 4f^14 5d^6
Atomic radius 185 pm
Covalent radius 144 pm
Boiling point 5012°C
Melting point 3033°C
Phase Solid
Fusion heat 31 kJ.mol^-1
Thermal expansion 5.1*10^-6 K^-1
Vaporization heat 630 kJ.mol^-1


Table Example
Color State gray
Brinell hardness 3920 MPa
Density 22590 kg.m^-3
Liquid density 20000 kg.m^-3
Mohs hardness 7
Poisson ratio 0.25
Shear modulus 222 GPa
Sound speed 4940 m.s^-1
Thermal conductivity 88 W.m^-1.K^-1
Vickers hardness 4140 MPa


Table Example
Electrical type Conductor
Magnetic type Paramagnetic
Resistivity 8.1*10^-8 Ohm.m
Superconducting point 0.66 K
Electronegativity 2.2
Valence 6
Electron affinity 106.1 kJ.mol^-1
First ionization energy 840 kJ.mol^-1
Radioactive No
Neutron cross section 15 barn