oxophenarsine

noun
oxo·​phen·​ar·​sine | \ ˌäk-sə-fen-ˈär-ˌsēn How to pronounce oxophenarsine (audio) , -sən How to pronounce oxophenarsine (audio) \

Medical Definition of oxophenarsine

: an arsenical formerly used in the form of its hydrochloride C6H6AsNO2·HCl to treat syphilis