Ir イリジウム
It has excellent hardness and corrosion resistance, and is used in automotive spark plugs,
To withstand high temperatures, it is used for manufacturing sapphire substrates for LEDs.
It is also used in crucibles.
For spark plugs
Iridium alloy tip
Iridium alloys resist corrosion and heat in harsh environments, contributing to longer plug lifespans.
In the cylinder of an engine, which is the heart of a car, compressed gasoline and air mixed gas undergo repeated ignition and explosions. Under the high temperature and harsh environment inside the engine, iridium alloy is used as the electrode at the tip of spark plugs (ignition plugs).
Precious Metal Element Data
| Atomic Number | 77 |
|---|---|
| atomic weight | 192.217 |
| Stable Isotope | 191Ir,193Ir |
| crystal structure | fcc |
| Metallic | Trans.Metal |
| Shell structure | 2,8,18,32,15,2 |
| Occupied Orbit | 5d7 |
| Oxidation state | 2,3,4,6 |
| Atomic radius | 1.87 |
| Shared bond radius | 1.36 |
| Atomic capacitance | 8.54 |
| Density (293K) | 22.42 |
| Melting point | 2446 |
| Boiling Point | 4437 |
| Specific heat | 0.130 |
| melting heat | 26.10 |
| heat of vaporization | 604.0 |
| Thermal conductivity (273K) | 147 |
| Electrical resistivity (273K) | 4.7 |
| Linear thermal expansion coefficient (293K) | 6.4 |
| First ionization potential | 8.96702 |
| Second ionization potential | |
| Electron Affinity | 1.5638 |
| Electronegativity | 2.2 |
| Year of Discovery | 1804 |
