Auripigment

AURIPIGMENT (from Latin aurum-gold and pigmentum-pigment), arsenic trisulfide, has the chemical formula As₂S₃. In nature, it is found in the form of a mineral having the same name and corresponding in composition to the formula given. In commerce, there is an artificially prepared A. often more contaminated than the natural one. The mineral A. is a crystal of the rhombic system, of light yellow color; the artificially prepared preparation is an amorphous powder, depending on the method of preparation - from light yellow to light brown color. A. is insoluble in water and hydrochloric acid. With solutions of caustic and carbonate alkalis, it forms water-soluble salts of arsenious and thio-arsenious acids: As₂S₃ + 6NaOH = Na₃AsO₃ + Na₃AsS₃ + 3H₂O. A. has no practically important derivative compounds. A. is used in technology as a pigment and laboratory reagent. When dissolved in alkalis, auripigment passes into thio-compounds, which have poisonous properties. Therefore, in terms of poisoning, work with technical auripigment, which always contains soluble arsenious compounds, can be dangerous; similarly, pure A. acts as a poison on mucous membranes, the secretions of which have an alkaline character. In medicine, auripigment was previously used

Figure 1. Stethoscope of ordinary type, wooden.

in some cases in the treatment of cancer, chancre; at present it is sometimes used as a depilatorium.