A series of thioacylsulfanylarsines ((RCS2)AsPh2, (RCS2)(2)AsPh, (RCS2)(3)As) were synthesized by treating piperidinium dithiocarboxylates with Ph2AsCl, PhAsCl2 or AsCl3, respectively and characterized. Their molecular structures were determined by X-ray crystallography and compared with those of the corresponding acylsulfanyl derivatives ((RCOS)AsPh2, (RCOS)(2)AsPh, (RCOS)(3)As). 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 thiocarboxylic acid derivatives ((RCOS)(2)AsPh, (RCOS)(3)As), respectively. The new compounds showed intramolecular interactions between the thiocarbonyl sulfur and the central arsenic atom. NBO (Natural Bond Orbital) analyses performed on the model compounds (CH3CS2)As(CH3)(2) and (CH3CS21)(CH3CS22)AsCH3 at the RHF/LANL2DZ level of theory showed the presence of interactions between the non-bonding orbitals on the thiocarbonyl sulfur (n(S)) and the sigma*(MS) orbitals together with that between the n(S) and the sigma*(MC) orbitals for the former compound; for the latter the presence of both orbital interactions between n(S) and sigma*(MS1) and between n(s) and sigma*(MS2) are present. The reaction of the mono(dithiocarboxylate) derivative (R epsilon=epsilon4-CH3C6H4) with piperidine in ethanol gave piperidinium diphenyldithioarsinate along with the corresponding N-thioacyl- or N-acyl-piperidine. A similar reaction of the bis(dithiocarboxylate) derivative (R epsilon=epsilon4-CH3C6H4) gave the novel di(piperidinium) phenyltrithioarsonate in which two anion charges are delocalized on the AsS3 moiety and a cyclic phenylarsine sulfide tetramer (PhAsS)(4). The diphenyldithioarsinate and phenyltrithioarsonate salts exist as a dimer and a polymer, respectively, in which 12-membered rings are formed by intermolecular N-H . . .S hydrogen bonds.