Note:  Do not rely on this information. It is very old.

Ferric Salts

Ferric Salts are salts of iron corresponding to ferric oxide (Fe2O3). When anhydrous they are usually colourless, but are of a yellow or brown colour When combined with water. The most important salt is ferric chloride FeCl3, which forms iron-black crystals, very deliquescent, dissolving to a brown liquid. Ferric salts may be readily distinguished by giving in solution a fine blue precipitate with potassium ferrocyanide and a blood-red coloration, even in dilute solutions, with ammonium sulphocyanate.