tartar emetic, poisonous, odorless, transparent rhombic crystals or white powder with a metallic, sweetish taste. Chemically, it is potassium antimony tartrate, KSbC4H4O7·1/2H2O. It is used as a mordant in dyeing. Medically, it was formerly used as an emetic and expectorant, to produce sweating, and in the treatment of several diseases, but had frequent toxic side effects.
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