cacodyl

Cacodyl, also known as cacodyl oxide or alkarsine, is a highly toxic organoarsenic compound with the chemical formula (CH3)2AsAs(CH3)2. It is a colorless, oily liquid that has a characteristic garlic-like or fishy odor. Historically, it was one of the first organometallic compounds to be synthesized, first being prepared by Robert Bunsen in the 1840s. Bunsen's work on cacodyl was groundbreaking and led to the concept of the "cacodyl radical," which was later understood to be a compound containing an arsenic-carbon bond.

Cacodyl is extremely volatile and ignites spontaneously in air, a property that contributed to its early notoriety and hazardous nature. Its toxicity stems from the presence of arsenic, which interferes with cellular respiration. Exposure can lead to severe poisoning symptoms, including gastrointestinal distress, neurological damage, and even death. Due to its extreme toxicity and flammability, cacodyl is not commonly used today. Its primary significance lies in its historical role in the development of organometallic chemistry and its demonstration of the existence of arsenic-carbon bonds.