Arsenic trioxide 三氧化二砷
（重定向自Ratsbane）
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![](/Images/godic/202502/06/As4O6-molecule-from-arsenolite-xtal-3D-balls5539.png")
![Historical arsenic mine Sankt Blasen, Austria](/Images/godic/202502/06/St.BlasenArsenikstollen55539.jpg")
![](/Images/godic/202502/06/Arsenolite-xtal-3D-balls-D5539.png")
Arsenic trioxide is an inorganic compound with the formula As
2O
3. This commercially important oxide of arsenic is the main precursor to other arsenic compounds, including organoarsenic compounds. Approximately 50,000 tonnes are produced annually. Many applications are controversial given the high toxicity of arsenic compounds.