Chromium
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Chemical formula | {{#Chem:Cr}} |
---|---|
Atomic Number | 24 |
OTP appearance | solid |
Density(g/cc) | 7.2 |
Melting Point(°C) | 1907 |
Boiling Point(°C) | 2671 |
Coefficient of Thermal Expansion(×10-6 °C-1) | 4.9 |
NFPA 704 |
Uses
Primary
- Stainless steel
- High speed steel
- Electroplating
Secondary
- Tanning
- Cleaning glassware via chromic acid
- Combined with Nickel for heating elements
Natural Occurrence
- Elemental chromium does not occur naturally
- Iron chromium oxide ({{#Chem: FeCr2O4}}) occurrs as the mineral Chromite
- Lead chromium oxide ({{#Chem: PbCrO4}}) occurrs as the mineral Crocoite
Hazards
Chromium is toxic and carcinogenic in its hexavalent state. Production of chromium metal often takes a path through (VI) to separate other materials, only to reduce it to (III) later. This makes chromium production via this path very dangerous.
Production
Extraction
See chromium processing for details on extracting both the pure metal and its various salts from naturally occurring chromite