Osmium (Os)
Osmium is element 76, a transition metal in period 6, group 8 of the periodic table. At room temperature it is a solid.
Electron configuration [Xe] 4f14 5d6 6s2
Electrons per shell 2, 8, 18, 32, 14, 2
Osmium data
| Atomic number | 76 |
|---|---|
| Symbol | Os |
| Atomic mass | 190.23 u |
| Category | Transition metal |
| Group | 8 |
| Period | 6 |
| Block | d |
| State at 25 °C | solid |
| Melting point | 3306 K (3032.9 °C) |
| Boiling point | 5285 K (5011.9 °C) |
| Density | 22.61 g/cm³ |
| Electronegativity (Pauling) | 2.2 |
| Atomic radius | 128 pm |
| 1st ionization energy | 840 kJ/mol |
| Electron affinity | -106 kJ/mol |
| Oxidation states | -2, -1, +1, +2, +3, +4, +5, +6, +7, +8 |
| Common ion charge | 4+ |
| Discovered | 1803 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through osmium’s configuration and its ions →
Where osmium sits
Osmium belongs to the transition metals. Its Pauling electronegativity of 2.2 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Osmium FAQ
What is the electron configuration of osmium?
Osmium (Z = 76) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d6 6s2. In noble-gas shorthand that is [Xe] 4f14 5d6 6s2.
How many valence electrons does osmium have?
8 (2 outer s + 6 d electrons; 2 in the outermost shell).
What is the atomic mass of osmium?
The standard atomic weight of osmium is 190.23 u, so one mole weighs 190.23 g.
Is osmium a metal?
Yes. Osmium is a transition metal.
What is the charge of a osmium ion?
Osmium most commonly forms Os4+.