of the corresponding acylsulfanyl derivatives ((RCOS)AsPh2, (RCOS)2AsPh, (RCOS)3As). They exist as monomers, and the environment around the arsenic atoms is distorted tetrahedral with one lone pair at the apex. The structure of the mono(dithiocarboxylate) is different from that of the corresponding thiocarboxylic acid derivative, while the bis and tris derivatives showed similar structure to the corresponding