|
|
|
||||
|
Iridium - Ir General Information Discovery Iridium was discovered by S. Tennant in 1803 in London. Appearance Iridium is a hard, lustrous, platinum-like metal. Source Iridium occurs uncombined in nature in alluvial deposits, and is recovered commercially as a by-product of nickel refining. Uses Iridium is used principally as a hardening agent for platinum. It also forms an alloy with osmium which is used for pen tips and compass bearings. It is the most corrosion-resistant material known, and was used in making the standard metre bar, which is an alloy of 90% platinum and 10% iridium. Biological Role Iridium has no known biological role, and has low toxicity. |
| Physical Information | |||
| Atomic Number | 77 | ||
| Relative Atomic Mass (12C=12.000) | 192.2 | ||
| Melting Point/K | 2683 | ||
| Boiling Point/K | 4403 | ||
| Density/kg m-3 | 22420 | ||
| Ground State Electron Configuration | [Xe]4f145d76s2 | ||
| Electron Affinity(M-M-)/kJ mol-1 | -190 |
| Key Isotopes | ||||||
| nuclide | 191Ir | 192Ir | 193Ir | |||
| atomic mass | 190.96 | 192.96 | ||||
| natural abundance | 37.3% | 0% | 62.7% | |||
| half-life | stable | 74.2 days | stable |
| Other Information | ||
| Enthalpy of Fusion/kJ mol-1 | 26.4 | |
| Enthalpy of Vaporisation/kJ mol-1 | 612.1 | |
| Oxidation States | ||
| main | Ir+3, Ir+4 | |
| others | Ir-1, Ir0, Ir+1, Ir+2, Ir+5, Ir+6 | |
| Ionisation Energies/kJ mol-1 | ||
| M - M+ | 880 | |
| M+ - M2+ | 1680 | |
| M2+ - M3+ | 2600 | |
| M3+ - M4+ | 3800 | |
| M4+ - M5+ | 5500 | |
| M5+ - M6+ | 6900 | |
| M6+ - M7+ | 8500 | |
| M7+ - M8+ | 10000 | |
| M8+ - M9+ | 11700 | |
| M9+ - M10+ | ||
|
|
|
|
|