The chemical symbol for Osmium is Os and its atomic number is 76.
We find it listed in the periodic table of elements in group 8 and period 6 and block.
The Osmium belongs to the family of transition metals such as for example the Silver, the Bohrium, cadmium, ...
This element is stable.
Atomic number (Z) 76
Group, block group 8, d-block
Period: period 6
Element category: transition metal
Standard atomic weight (±) (Ar) 190.23(3)
Electron configuration [Xe] 4f14 5d6 6s2
per shell: 2, 8, 18, 32, 14, 2
Physical properties
Phase: solid
Melting point: 3306 K (3033 °C, 5491 °F)
Boiling point: 5285 K (5012 °C, 9054 °F)
Density near r.t. : 22.59 g/cm3
when liquid, at m.p. 20 g/cm3
Heat of fusion: 31 kJ/mol
Heat of vaporization: 378 kJ/mol
Molar heat capacity: 24.7 J/(mol·K)
Atomic properties
Oxidation states; 8, 7, 6, 5, 4, 3, 2, 1, 0, −1, −2, −4 (a mildly acidic oxide)
Electronegativity: Pauling scale: 2.2
Ionization energies 1st: 840 kJ/mol
2nd: 1600 kJ/mol
Atomic radius empirical: 135 pm
Covalent radius: 144±4 pm
Crystal structure: hexagonal close-packed
Speed of sound thin rod: 4940 m/s (at 20 °C)
Thermal expansion: 5.1 µm/(m·K) (at 25 °C)
Thermal conductivity: 87.6 W/(m·K)
Electrical resistivity: 81.2 nΩ·m (at 0 °C)
Magnetic ordering: paramagnetic
Shear modulus : 222 GPa
Bulk modulus: 462 GPa
Poisson ratio/ 0.25
Mohs hardness: 7.0
Brinell hardness: 3490–4000 MPa
CAS Number: 7440-04-2