Schweinfurt Green

Schweinfurt Green.

Schweinfurt green, the most beautiful green copper colour, a compound of acetate of copper with arsenic of copper (C2H3O2)2Cu+3(CuAs2O4), is prepared by mixing a solution of verdigris or neutral acetate of copper (or of sulphate of copper with acetate of soda or acetate of lime) felled with a solution of arsenic acid. Schweinfurt Green is all the more coarse-grained, crystalline and darker the more slowly it formed; but when crushed it always assumes the colour of the rapidly produced, less crystalline preparation. Schweinfurt Green is a magnificent green, insoluble in water, decomposes when boiled with water for a long time, is unchangeable in light and air, but is decomposed by hydrogen sulfide and quicklime, on wallpaper in damp locations it emits a volatile arsenic compound, probably arsine. It is very toxic and its use is therefore restricted, namely it must not be used where it comes into direct contact with the skin or where dust can be inhaled. It doesn’t cover very well in oil, but dries well. It is used as oil and water paint. In the trade it is usually shaded with gypsum, barite, sulphate of lead or chrome yellow (Mineral, Patent, Imperial, Royal, Kassel, Vienna, Paris, Neuwied, Kirchberg, Parrot, Mitis, English, Original Green etc.).

Source: Meyers Großes Konversations-Lexikon, 6. Auflage 1905–1909