Scheele’s Green

Chemical Designations - Synonyms Cupric Arsenite Swedish Green Scheele s Green Cupric Green Copper Orthoarsenite Chemical Formula CuHAsO ... 

Swedish green (Scheele s green). —schwedl-sches Hblzchen, n. safety match. Schwedlsch, Schwedische, n. Swedish (language). 

The pigment industry started in the 18th century with products such as Berlin blue (1704), cobalt blue (1777), Scheele s green, and chrome yellow (1778). 

Cupric Acid Orthoarsenite (Scheele s Green). CuHAsOj, green powder, insoluble in H 0, soluble in alcohol, acids, and NHjOH. Used as a wood preservative. 

Cupric arsenltes.—A pigment of varying composition is prepared as a canary-green precipitate by mixing solutions of an alkali-metal arsenite and cupric sulphate.12 It is known as Scheele s green. Other cupric derivatives of arsenious acid are also known.18... 

The levels of arsenic found, up to 11 ppm, are more consistent with therapeutic use of arsenic, such as in Fowler s solution (see p. 224). An alternative explanation is that the wallpaper and draperies in the house where he lived were coloured with pigments, such as Scheele s green dye (copper arsenite), which contained arsenic. Samples of the wallpaper have been found which do indeed contain arsenic, it is known that in damp conditions, in the presence of mould, this dye wiii reiease a voiatiie organic form of arsenic, methylarsine, which is very toxic. Such a case of poisoning occurred more recently in the US Embassy in Rome in the 1950s. 

While the use of sugar of lead as a sweetener died out after the fall of the Roman Empire, the use of lead salts in food did not. Much more recently, for example, lead chromate, or chrome yellow , has been used to colour sweets and custard powder. As recently as the nineteenth century toxic metal salts were used as food colourants, for example the dye Scheele s green was used to colour blancmanges green. This dye is copper arsenite, containing both copper and, more importantly, arsenic. 

Butter Yellow and Scheele s Green Food Additives... 

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