Chem.
a compound that in its anhydrous form, FeCl 3 , occurs as a black-brown, water-soluble solid; in its hydrated form, FeCl 3 ·xH 2 O, it occurs in orange-yellow, deliquescent crystals: used chiefly in engraving, for deodorizing sewage, as a mordant, and in medicine as an astringent and styptic. Also called iron trichloride, iron perchloride .
[ 1890-95 ]