cacodyl \cac"odyl\, n. gr. ??????? ill-smelling kako`s bad +
   ????? to smell + -yl. chem.
   alkarsin; a colorless, poisonous, arsenical liquid,
   as2ch34, spontaneously inflammable and possessing an
   intensely disagreeable odor. it is the type of a series of
   compounds analogous to the nitrogen compounds called
   hydrazines. written also cacodyle, and kakodyl.
   1913 webster
see also:
as2ch34 cacodyle kakodyl