A hydrated form of copper arsenite, formerly used as a pigment in calico printing and wallpaper manufacture, warm yellowish-green in color with good opacity, but never widely used as a paint pigment because it is toxic and discolors in the presence of acid or sulfur fumes. Currently, copper arsenite is used as a rodenticide, insecticide, fungicide, and wood preservative. Scheele's green was discovered in Sweden in 1775 by Carl W. Scheele, a German chemist, but he did not publish the recipe until 1778.
