Thiolated arsenic compounds are the sulfur analogous substructures of oxo-arsenicals as the arsinoyl (As=O) is substituted by an arsinothioyl (As=S) group. Relatively brief history of thioarsenic research, mostly in the current decade has endeavored to understand their consequences in the natural environment. However, thioarsenic related aspects have by far not attached much research concern on global scale compared to other arsenic species. This paper provides a critical overview on formation mechanisms of thioarsenicals and their chemistry aiming to direct future research towards thioasenic mitigation strategies. Sulfur-arsenite/arsenate interactions and dissolution of arsenic sulfide minerals are the main mechanisms that involve in the formation of different thioarsenic species in the natural environment. The formation and chemical analysis of thioarsenicals in soil and sediments are highly unknown. Future research needs to be more inclined towards in determining the molecular structure of unknown thioarsenic complexes in various environmental suites.