Periodic Table of Elements

76

Osmium

190.23

Osmium was discovered in 1804 by English chemist Smithson Tennant (1761-1815).

Name: Osmium
Symbol: Os
Atomic number: 76
Atomic weight: 190.23
State: solid
Group, period, block: 8, 6, d
Color: silvery, blue cast
Classification: transition metal
Electron configuration: 4f14 5d6 6s2
2,8,18,32,14,2

Physical properties

Density: 22.59 g/cm-3
Melting point: 3306 K, 3033 C, 5491 F
Boiling point: 5285 K, 5012 C, 9054 F

Atomic properties

Oxidation states: 8, 7, 6, 5, 4, 3, 2, 1, 0, -1, -2
Electronegativity: 2.2 (Pauling scale)
Ionization energies: 1st: 840 kJmol-1
Covalent radius: 1444 pm
Van der Waals radius: no data
  • Os
  • Electron Configuration

Isotopes

There are seven naturally occurring isotopes of osmium exist, 184Os, 186Os, 187Os, 188Os, 189Os, 190Os, and 192Os.