Element 76
Osmium (Os)
Osmium (Os) is element 76 of the periodic table, a transition metal in period 6, group 8 (d-block) with an atomic mass of 190.23 and is a solid at standard conditions.
At a glance
- Atomic number
- 76
- Symbol
- Os
- Atomic mass
- 190.23 u
- Category
- Transition metals
- Period
- 6
- Group
- 8
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d6 6s2
- Shorthand configuration
- [Xe] 4f14 5d6 6s2
- Electrons per shell
- 2, 8, 18, 32, 14, 2
- Oxidation states
- -4, -2, -1, +1, +2, +3, +4, +5, +6, +7, +8
Physical properties
- Melting point
- 3306 K
- Boiling point
- 5285 K
- Density
- 22.59 g/cm3
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 2.2
- Atomic radius
- 185 pm
- Covalent radius
- 144 pm
- First ionization energy
- 840 kJ/mol
- Electron affinity
- 104 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Os-192 | 191.96148 | 40.78% | Stable |
Common uses
- Fountain pen tips
- Electrical contacts
- Fingerprint detection
- Alloys
Discovery
- Year
- 1803
- Discovered by
- Smithson Tennant
- Country
- England