Arsenic trioxide is a highly toxic compound that is commonly used as a chemical weapon and in pesticides and herbicides. There are several synonyms for arsenic trioxide, including arsenic oxide, arsenic(III) oxide, arsenious acid and arsenious oxide. It is also known by its chemical formula As2O3 and the mineral name arsenolite. Arsenic trioxide is often used in medicine as a treatment for certain types of leukemia, and it has been used in traditional Chinese medicine for centuries. However, due to its toxic properties, it must be handled with care and in accordance with strict safety protocols.