Abstract Arsinogermylenes, Arsinostannylenes Tin dichloride and the germanium dichloride dioxane complexes react with tri-£er£-butyl-+ — arsane to give ylide-type 1:1 complexes <-Bu3As-MCl2 (M = Sn, Ge). With di-ter£-butyl-(trimethylsilyl)arsane substitution reactions lead to the formation of chlorotrimethylsilane and the arsino-substituted chlorostannylenes and -germylenes £-Bu2As-MCl. Physical properties of these compounds indicate the presence of associated structures with bridging arsino groups and terminal M-Cl functions.