The term "cacodyl radical" refers to a highly toxic and volatile organic compound that contains a dimethylarsenic group (-As(CH3)2). It is also known by several synonyms such as dimethylarsenic group, cacodyl, and dimethylarsenyl. This chemical compound was first synthesized in the 18th century and was found to be a major precursor in the production of organoarsenic compounds. Despite its toxic nature, cacodyl radical was extensively used in the past for medicinal purposes, including the treatment of syphilis. However, due to its harmful effects, it has been banned from medical use and is only used for research purposes.