Osmium
Main page |
| Other names/abbreviations: | Os |
| Element no: | 76 |
| Element group: | 8 (IUPAC) VIII B (American labelling) VIII A (European labelling) |
| Element type: | Transition metals |
| CAS-Number: | 7440-04-2 |
| EINECS-Number: | 231-114-0 |
Safety
Symbol: T+R-phrases: 26/27/28-34
S-phrases: 26-28-36/37/39-45
Physical properties
Appearance | ||
| Physical state @ 20°C: | Solid [4] | |
| Color: | Gray [4] | |
| Odor: | Odourless [4]. Pungent smell from osmium (VIII) oxide. | |
Bulk properties | ||
| Molecular weight (g/mol): | 190.23(3) [1] | |
| Melting point (°C): | 3033 [3] | |
| Boiling point (°C): | 5012 [3] | |
| Density (g/cm3): | 22.59 [1] | |
| Molar volume (cm3): | 8.45 (20 °C) [2] | |
| Elastic properties: Young's modulus (GPa): Rigidity modulus (GPa): Bulk modulus (GPa): Poisson ratio: |
560-570 [2] 224 [2] 373 [2] 0.25 [2] | |
Thermodynamic properties | ||
| ΔfH°gas (kJ/mol): | 791.0 [3] | |
| ΔfH°solid (kJ/mol): | 0.0 [3] | |
| ΔH°fusion (kJ/mol): | 57.85 [3] | |
| S°gas (J/K·mol): | 192.6 [3] | |
| S°solid (J/K·mol): | 32.6 [3] | |
| ΔfG°gas (kJ/mol): | 745.0 [3] | |
| Cp (gas) (J/K·mol): | 20.8 (25 °C) [3] | |
| Cp (solid) (J/K·mol): | 24.7 (25 °C) [3] | |
| Coeff. of linear thermal expansion (106 K-1): | 5.1 (25 °C) [3] | |
Crystal structure | ||
| Crystal type: | HCP [2] | |
Electronic properties | ||
 |
Electron configuration: | 1s2-2s2-2p6-3s2-3p6-3d10-4s2-4p6-4d10-4f14-5s2-5p6-5d6-6s2 |
| Ionic radius (Å): | Os(VIII): 0.39 (4-coordinate) [1] Os(VII): 0.525 (6-coordinate) [1] Os(VI): 0.545 (6-coordinate) [1] Os(V): 0.575 (6-coordinate) [1] Os(IV): 0.63 (6-coordinate) [1] | |
Conductivity | ||
| Electrical resisitvity (μΩ·cm): | 8.8 (20 °C) [2] 8.4 (25 °C) [2] | |
| Thermal (W/m·K): | 87.6 (27 °C) [3] | |
References
1: Greenwood,N.N., Earnshaw,A. Chemistry of the elements2nd edition (1997) Edited by Greenwood,N.N., Earnshaw,A. pp. 1-1340, Butterworth-Heinemann. Oxford. Great Britain
2: Buch,A. Pure Metals Properties. A Scientific-Technical Handbook
1st edition (1999) Edited by Buch,A. pp. 1-306, ASM International and Freund Publishing House Ltd. Ohio. USA
3: CRC Handbook of Chemistry and Physics
75th edition (1994) Edited by Lide,D.R. , CRC Press Inc. Boca Raton, USA
4: Merck. ChemDAT The Merck Chemical Database Ver. 1.1.5
© Michael Pilgaard
Created: October 4, 2008
Last update: October 9, 2008