Osmium is a chemical element that has the symbol Os and atomic number 76. Osmium is a hard, brittle, blue-gray or blue-black transition metal in the platinum family, and is one of the densest natural elements, competing for this status with iridium. Osmium is used in alloys with platinum, iridium and other platinum group metals. Osmium is found in nature as an alloy in platinum ore. Alloys of osmium are employed in fountain pen tips, electrical contacts and in other applications where extreme durability and hardness are needed.
Technical Data
Symbol |
Os |
Melting point / °C |
3045(+/-30) |
Atomic number |
76 |
Boiling point / °C |
5025(+/-100) |
No. of naturally occurring isotopes |
7 |
ΔHfus/kJmol-1 |
31.7 |
Atomic weight |
190.2 |
ΔHvap/kJmol-1 |
738 |
Electronic configuration |
[Xe]4fJ45d66s2 |
ΔHf(monoatomic gas)/kJmol-1 |
791 (+/-13) |
Metal radius(12-coordinate)/pm |
135 |
Electrical resistivity |
|
Ionic radius(4-coordinate)/pm VIII |
39 |
(20°C)/μohm cm |
8.12 |
Ionic radius(6-coordinate)/pm VII |
52.5 |
Electronegativity χ |
2.2 |
Ionic radius(6-coordinate)/pm VI |
54.5 |
Ionization energy/kJmol-1 I |
840 |
Ionic radius(6-coordinate)/pm V |
57.5 |
Ionization energy/kJmol-1 II |
1600 |
Ionic radius(6-coordinate)/pm IV |
63 |
Ionization energy/kJmol-1 III |
2400 |
Density (20°C)/gcm-3 |
22.57 |
|
|
Evaporation Techniques
Temperature (oC) @Vap. Pressure |
Techniques |
Remarks |
10-8 Torr |
10-6 Torr |
10-4 Torr |
Electron Beam |
Crucible |
Coil |
Boat |
2170 |
2430 |
276 |
Fair |
- |
- |
- |
|