text: The first activation of a main group compound by yellow arsenic was reported in 1992 by West and coworkers, involving the reaction of As with a disilene compound, tetramesityldisilene, to generate a mixture of compounds including a butterfly structural motif of bridging arsenic atoms. Notably, the product mixture obtained in this reaction differs from the analogous reaction with P that produces the butterfly compound alone, highlighting that the reactivity of yellow arsenic and white phosphorus cannot be considered identical. The first organo-substituted As compound was produced by Scheer and coworkers in 2016 via reaction with the Cp radical. Analogous to the butterfly compound obtained by the West group, the product obtained in this reaction featured a bridging As motif that reversibly returned As and the parent radical in the presence of light or heat. This characteristic makes the CpAs complex a uniquely suitable "storage" molecule for yellow arsenic, as it is stable when stored at room temperature in the dark, but can release As in thermal or photochemical solutions. 
  Other reactions of main group compounds with yellow arsenic have been shown to involve units of arsenic with more than four atoms. In reaction with the silylene compound [PhC(NtBu)SiN(SiMe)], an aggregation of As was observed to form a cage compound of ten arsenic atoms, including a seven-membered arsenic ring at its center.