|
|
| Osmium | |
| Electron Configuration | 2,8,18,32,14,2 |
| Electron Configuration | [Xe] 4f14 5d6 6s2 |
| Ground state | 5D4 |
| Atomic Volume | 8.49 g/cm3 |
| Electronegativity | 2.2 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 6 x 10-10 |
| Molar magnetic susceptibility | 1.1 x 10-10 |
| Speed of sound | 4940 m s-1 |
 Thermal Properties |
|
| Enthalpy of Atomization | 669 kJ mol-1 @25°C |
| Enthalpy of Fusion | 29.3 kJ mol-1 |
| Enthalpy of Vaporisation | 738 kJ mol-1 |
| Heat Capacity | 24.7 J mol-1 K-1 |
| Thermal Conductivity | 87.6 W m-1 K-1 |
| Thermal Expansion | 5.1 μm m-1 K-1 |
| Hardness |
|
| Brinell hardness | 3920 MPa |
| Mohs hardness | 7.0 |
| Elastic Properties |
|
| Bulk modulus | 462 GPa |
| Poisson ratio | 0.25 |
| Shear modulus | 222 GPa |
| Electrical Properties |
|
| Electrical resistivity | 8.1 x 10-8 Ω m |
| Electrical conductivity | No data. |
| Chemical Properties |
|
| Electrochemical Equivalent | 1.774 g Ah-1 |
| Electron Work Function | 4.83 eV |
| Valence Electron Potential (-eV) | 91.4 |
| Ionization Potential | |
 First
|
8.7 |
| Energy Levels |
|
| Kα1 (intensity 100) |
63.0005 KeV |
| Kα2 (intensity 50) |
61.4867 KeV |
| Kβ1 (intensity 26.1) |
71.413 KeV |
| Kβ2 (intensity 10.5) |
72.1286 KeV |
| Kβ3 (intensity 10.1) |
71.3991 KeV |
| Lα1 (intensity 100) |
8.9117 KeV |
| Lα2 (intensity 10) |
8.841 KeV |
| Lβ1 (intensity 39) |
10.3553 KeV |
| Lβ2 (intensity 19) |
10.5985 KeV |
| Lβ3 (intensity 6.5) |
10.5074 KeV |
| Lβ4 (intensity 4) |
10.1738 KeV |
| Lγ1 (intensity 6) |
12.0953 KeV |
| Lγ2 (intensity 2) |
12.4182 KeV |
| Lγ3 (intensity 2) |
9.334 KeV |
| Ll (intensity 4.5) |
7.8206 KeV |
| Atomic Radii |
|
| Empirical
|
130 pm |
| Bohr Radius
|
185 pm |
| Covalent Radius
|
128 pm |
| Van der Waals
|
No data. |
| Triple covalent
|
109 pm |
| Metallic
|
135 pm |
| Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 4 | VI | 0.77 | 0.63 | RM |
| 5 | VI | 0.715 | 0.575 | E |
| 6 | V | 0.63 | 0.49 | |
| VI | 0.685 | 0.545 | E | |
| 7 | VI | 0.665 | 0.525 | E |
| 8 | IV | 0.53 | 0.39 | |
| R, From r3 vs V plots. |
| C, Calculated from bond length - bond strength equations. |
| E, Estimated. |
| *, Most Reliable. |
| M, From Metallic Oxides. |
| A, Ahrens (1952) Ionic radius. |
| P, Pauling's (1960) Crystal Radius. |
| Oxidation States |
|
| Main
|
Os+4 |
| Other
|
Os-2, Os0, Os+1, Os+2, Os+3, Os+5, Os+6, Os+7, Os+8 |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
840 |
| M+ - M2+ |
1600 |
| M2+ - M3+ |
2400 |
| M3+ - M4+ |
3900 |
| M4+ - M5+ |
5200 |
| M5+ - M6+ |
6600 |
| M6+ - M7+ |
8100 |
| M7+ - M8+ |
9500 |
| Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 3160 | 3423 | 3751 | 4148 | 4638 | 5256 |
| Crystal Structure |
|
| Structure
|
Hexagonal close packed |
 |
a = 273.44 pm |
| b = 273.44 pm | |
| c = 431.73 pm | |
| α = 90° | |
| β = 90° | |
| γ = 120° | |