Iridium
☄️ In Your World
Iridium is the second-densest element and the most corrosion-resistant metal known. It is famous for providing the "smoking gun" evidence for the asteroid impact that wiped out the dinosaurs. A thin layer of iridium, rare on Earth but common in asteroids, was found globally in the rock layer corresponding to that time (the K-Pg boundary). Today, its hardness and high melting point make it ideal for high-performance spark plugs and crucibles for growing crystals.
📖 The Discovery Story
Iridium was discovered in 1803 by English chemist Smithson Tennant, at the same time he discovered osmium. He found it in the dark, insoluble residue left after dissolving platinum ore in aqua regia. He named it "iridium" from the Latin word iris, meaning "rainbow," because its salts are highly and variably colored.
📊 Properties at a Glance
| Phase at STP | Solid |
| Melting Point | 2446 °C / 4435 °F |
| Boiling Point | 4428 °C / 8002 °F |
| Electron Configuration | [Xe] 4f¹⁴5d⁷6s² |
| Abundance in Earth's Crust | 0.0000001% |
⚠️ Safety & Handling
Iridium metal is very unreactive and is not considered toxic, making it safe to handle. Its compounds, however, should be treated as potentially toxic and handled with standard laboratory precautions.