Osmium (Os): Electron Configuration, Properties and Uses
Osmium (Os): Electron Configuration, Properties and Uses
Electron configuration [Xe] 6s2 4f14 5d6 · group 8 · period 6 · Ar 190.23
Osmium data
- Atomic number
- 76
- Relative atomic mass
- 190.23
- Group
- 8
- Period
- 6
- Block
- d
- Category
- Transition metal
- Electron configuration
- [Xe] 6s2 4f14 5d6
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d6
- Electrons per shell
- 2, 8, 18, 32, 14, 2 (K L M N O P)
- Valence electrons
- 8
- Electronegativity (Pauling)
- 2.2
- First ionisation energy
- 8.7 eV
- Atomic radius (van der Waals)
- 216 pm
- State at room temperature
- Solid
- Melting point
- 3033 °C
- Boiling point
- 5012 °C
- Density
- 22.57 g/cm³
- Common oxidation states
- +4, +3
- Discovered
- 1803
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 18 · N 32 · O 14 · P 2
Orbital diagram (outer electrons)
About osmium
With atomic number 76, osmium (Os) has 76 protons in its nucleus and 76 electrons as a neutral atom. It is a transition metal in group 8, period 6, d-block. Osmium was first discovered in 1803. Osmium is a solid at room temperature, melting at 3033 °C and boiling at 5012 °C. At 22.57 g/cm³, osmium is the densest element ever measured.
Osmium electron configuration
The electron configuration of osmium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d6, or in short [Xe] 6s2 4f14 5d6. Its electrons occupy 6 shells: K = 2, L = 8, M = 18, N = 32, O = 14, P = 2. For transition metals, valence electrons are counted from the 6s and 5d subshells: 2 + 6 = 8, matching group 8. When it forms cations, electrons leave the outermost subshell first: Os3+ = [Xe] 4f14 5d5; Os4+ = [Xe] 4f14 5d4.
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12) → 3p6(18) → 4s2(20) → 3d10(30) → 4p6(36) → 5s2(38) → 4d10(48) → 5p6(54) → 6s2(56) → 4f14(70) → 5d6(76)
Uses of osmium
In industry and the laboratory, osmium turns up in many places, for example hard alloys for pen tips and electrical contacts, and osmium tetroxide for electron-microscopy staining and dihydroxylation. For research and analysis you can browse osmium compounds in the AMI Scientific catalogue.
Safety
Osmium tetroxide is highly toxic and its vapour can damage the eyes. Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 8
Frequently asked questions
What is the electron configuration of osmium?
The electron configuration of osmium (Os, atomic number 76) is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d6, or [Xe] 6s2 4f14 5d6 in short. By shell: 2, 8, 18, 32, 14, 2.
How many valence electrons does osmium have?
Osmium has 8 valence electrons.
Which group and period is osmium in?
Osmium is in group 8, period 6, d-block.
What is the atomic mass of osmium?
The relative atomic mass of osmium is 190.23. Use it to calculate molar mass with the molar mass calculator.
Need osmium compounds for your lab?
AMI Scientific is one of the official TCI distributors in Indonesia. Reagents with lot CoA & SDS, formal quotations and tax invoices for universities and laboratories.
Other formulas & calculators: molarity, mole, molality, normality, dilution, titration, pH, buffer, molar mass, ppm, mole fraction, mass percent, periodic table, chemical MSDS.
