Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point.
Three reasons Chromium stands out
- 1
Often seen in the shiny finish of cars.
- 2
It is the element that makes stainless steel stainless, by forming a self-repairing protective oxide layer.
- 3
The vivid red colour of rubies is caused by trace amounts of this element inside the gemstone.
A protective shine only atoms thick
Chromium gives stainless steel its defining resistance to rust. Oxygen creates a transparent chromium-rich film that seals scratches almost as soon as they appear. Chromium compounds also span vivid pigments and industrial hazards: the trivalent form is far less dangerous than strongly oxidizing hexavalent chromium.