Chromium compounds are found in the environment. The concentration range in soil is between 1 and 300mg/kg, in sea water 5 to 800µg/liter, and in rivers & lakes 26µg/liter.
Chromium is mined as Chromite (FeCr2O4) ore.
It is a steely-gray, lustrous, hard & brittle metal, which takes a high polish, resists tarnishing, and has a high melting point.
Chromium, unlike metals such as iron & nickel, does not suffer from Hydrogen Embrittlement. However, it does suffer from nitrogen embrittlement.
Chromium Trioxide (CrO3) is produced by mixing Crocoite (Lead Chromate) ore with Hydrochloric Acid.
