A mixture of dicacodyl and cacodyl oxide ((CH3)2As–O–As(CH3)2) was first prepared by Cadet by the reaction of potassium acetate with arsenic trioxide.

A subsequent reduction yields a mixture of several methylated arsenic compounds including dicacodyl.

The global reaction (mass balance) corresponding to the oxide formation is the following: A more efficient synthesis was later developed which started from the dimethyl arsine chloride and dimethyl arsine: Robert Wilhelm Bunsen coined the name kakodyl (later modified to cacodyl in English) for the dimethylarsinyl radical, (CH3)2As, from the Greek κακώδης kakōdēs ("evil-smelling") and ὕλη hylē ("matter").

[2] It was investigated by Edward Frankland and (for over six years) by Robert Bunsen and is considered the earliest organometallic compound discovered (even though arsenic is not a true metal).

[3] As this was prior to the invention of the fume hood, to avoid the unpleasant odor of the chemical Bunsen worked quickly and breathed through a long glass tube that extended to the outside of his laboratory.