Iridium
Main page |
| Other names/abbreviations: | Ir |
| Element no: | 77 |
| Element group: | 9 (IUPAC) VIII B (American labelling) VIII A (European labelling) |
| Element type: | Transition metals |
| CAS-Number: | 7439-88-5 |
| EINECS-Number: | 231-095-9 |
Physical properties
Appearance | ||
| Physical state @ 20°C: | Solid | Color: | Silvery-white |
Bulk properties | ||
| Molecular weight (g/mol): | 192.217(3) [1] | |
| Melting point (°C): | 2443 [1] | |
| Boiling point (°C): | 4550±100 [1] | |
| Density (g/cm3): | 22.56 [1] | |
| Molar volume (cm3): | 8.53 (20 °C) [2] | |
| Elastic properties: Young's modulus (GPa): Rigidity modulus (GPa): Bulk modulus (GPa): Poisson ratio: |
520-538 [2] 209 [2] 371 [2] 0.26 [2] | |
Thermodynamic properties | ||
| ΔfH°gas (kJ/mol): | 669±8 [1] 665.3 [3] | |
| ΔfH°solid (kJ/mol): | 0.0 [3] | |
| ΔH°fusion (kJ/mol): | 26.4 [1] 41.12 [3] | |
| ΔH°vaporization (kJ/mol): | 612±13 [1] | |
| S°gas (J/K·mol): | 193.6 [3] | |
| S°solid (J/K·mol): | 35.5 [3] | |
| ΔfG°gas (kJ/mol): | 617.9 [3] | |
| Cp (gas) (J/K·mol): | 20.8 (25 °C) [3] | |
| Cp (solid) (J/K·mol): | 25.0207 (20 °C) [2] 25.1 (25 °C) [3] 25.7448 (100 °C) [2] 27.2734 (500 °C) [2] 30.5719 (1000 °C) [2] | |
| Coeff. of linear thermal expansion (106 K-1): | 6.4 (25 °C) [3] 6.8 (100 °C) [2] 7.2 (500 °C) [2] 7.8 (1000 °C) [2] | |
Crystal structure | ||
| Crystal type | Face centered cubic [2] | |
Electronic properties | ||
 |
Electron configuration: | 1s2-2s2-2p6-3s2-3p6-3d10-4s2-4p6-4d10-4f14-5s2-5p6-5d7-6s2 |
| Ionic radius (Å): | Ir(V): 0.57 (6-coordinate) [1] Ir(IV): 0.625 (6-coordinate) [1] Ir(III): 0.68 (6-coordinate) [1] | |
Conductivity | ||
| Electrical resisitvity (μΩ·cm): | 5.1 (20 °C) [2] 5.0 (25 °C) [2] 6.8 (100 °C) [2] 15.1 (500 °C) [2] | Thermal (W/m·K): | 147 (27 °C) [3] 147 (300 °C) [2] 136 (600 °C) [2] 125 (1000 °C) [2] |
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
© Michael Pilgaard
Created: October 2, 2008