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|Section2= |Section3= }} Scheele's Green, also called Schloss Green, is chemically a cupric hydrogen arsenite (also called copper arsenite or acidic copper arsenite), CuHAsO3. It is chemically related to Paris Green. It is a yellowish-green pigment and in the past it was used in some paints, but has since fallen out of use because of its toxicity and the instability of its colour in the presence of sulphides and various chemical pollutants. Scheele's Green was invented in 1775 by Carl Wilhelm Scheele.〔(StudioMara - History of Pigments )〕 By the end of the 19th century, it virtually replaced the older green pigments based on copper carbonate. ==Preparation== The pigment was originally prepared by making a solution of sodium carbonate at a temperature of around 90 °C, then slowly adding arsenious oxide, while constantly stirring until everything had dissolved. This produced a sodium arsenite solution. Added to a copper sulfate solution, it produced a green precipitate of effectively insoluble copper arsenite. After filtration the product was dried at about 43°C. To enhance the color, the salt was subsequently heated to 60-70 °C. The intensity of the color depends on the copper : arsenic ratio, which in turn was affected by ratio of the starting materials, as well as the temperature. It has been found that Scheele's green was composed of a variety of different compounds, including copper metaarsenite (CuO•As2O3), copper arsenite salt (CuAsHO3 and Cu(AsO3)2•3H2O)), neutral copper orthoarsenite (3CuO•As2O3•2H2O), copper arsenate (CuAsO2 and Cu(AsO2)2), copper diarsenite (2CuO•As2O3•2H2O). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Scheele's Green」の詳細全文を読む スポンサード リンク
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