Potassium dichromate, K2Cr2O7, is a salt used in a number of industrial processes and products including:

General description

Bright orange crystals
Molecular formula: K2Cr2O7
Molecular weight: 294.18
EEC No. 231-906-6
CAS No. 7788-50-9
True density: 2.68g/cm3
Bulk density (approx): 1.6g/cm3
Soluble in water, at 20°C approx. 12% w/w, at 100°C approx. 50% w/w
A strong oxidising agent particularly in acidic conditions.
Melting point: 398°C (begins to decompose into oxygen, potassium and green chromium oxide at about 500°C)


  1. Potassium dichromate is nasty stuff - a dose of 4 to 10g will kill an adult if ingested. Depending on the concentration, it can also cause a severe burn if it comes into contact with your skin, permanent eye damage if it comes into contact with your eye and an allergic reaction.
  2. Potassium dichromate is a controlled substance in certain jurisdictions as it is used in the production of certain illegal drugs

Notes and sources

  • EEC is an (obsolete) abbreviation for European Economic Community. It was replaced by EC, an abbreviation for European Community, in 1996 although the older EEC abbreviation seems to still be quite prevalent.
  • CAS is an abbreviation for Chemical Abstract Service, a division of the American Chemical Society.
  • w/w indicates that the concentration is expressed as the weight of the solute divided by the weight of the solution (i.e. solute plus solvent)
  • the "General Description" section was taken nearly verbatim from the web site of Elementis plc, the (self-described) world's largest supplier of chromium chemical products. This web site also provided much of the information (but none of the sentences) in the rest of this writeup. Their web site is located at www.elementischromium.com (last referenced 2003/02/13).
  • the lethal dosage for potassium dichromate was taken from http://www.rhodium.ws/chemistry/potassium.dichromate.html (last referenced 2003/02/13)

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