Scheele's Green

Synonyms:

Scheele's Green, Cupric Arsenite, Swedish Green, Mitis Green, Scheeles Grün

This pigment, discovered in 1778, is an arsenite of copper with an excess of copper oxide. It is best prepared by dissolving, in separate portions of hot water, white arsenic and blue vitriol. The solutions are then mixed, and to the mixture is added, in small successive portions, a solution of potassium carbonate. These additions are stopped when the precipitated pigment has attained its maximum of colour intensity. In another process, a hot solution of potassium arsenite is added to a hot solution of blue vitriol. This pigment needs thorough washing with hot water, and must be dried at a moderate temperature.

Scheele's green presents nearly the same characteristics as emerald green, but is in every way inferior to that pigment. It is eminently poisonous. It should not find a place on the palette of the artist.

Vienna green, Mitis green, and Veronese green are names which have been given to specially prepared varieties of this cupric arsenite; but there are very many other designations by which pigments of essentially the same composition are known. They are prepared by slightly modified processes, and frequently contain such foreign matters as chalk, heavy spar, or gypsum.