Chromium
🚗 In Your World
Chromium is what gives stainless steel its resistance to rust and corrosion. It's also used for chrome plating on cars and motorcycles, giving them a hard, shiny, and protective finish. The name "chromium" comes from the Greek word chroma, meaning color, because its compounds are famous for being intensely colorful. For example, chromium is what gives rubies their red color and emeralds their green.
📖 The Discovery Story
In 1797, French chemist Louis Nicolas Vauquelin received samples of a red lead ore from Siberia. By reacting the mineral with acid, he was able to precipitate lead chromate. In 1798, he successfully isolated the pure metallic chromium by heating the oxide with charcoal. He was astonished by the wide variety of colors he could produce from its compounds, which inspired the element's name.
📊 Properties at a Glance
| Phase at STP | Solid |
| Melting Point | 1907 °C / 3465 °F |
| Boiling Point | 2671 °C / 4840 °F |
| Electron Configuration | [Ar] 3d⁵4s¹ |
| Abundance in Earth's Crust | 0.0102% |
⚠️ Safety & Handling
Chromium metal and its trivalent (Cr³⁺) compounds are considered safe and are even an essential trace nutrient for humans. However, hexavalent chromium (Cr⁶⁺) is highly toxic and carcinogenic (cancer-causing) if inhaled. This form is a serious environmental pollutant and occupational hazard.