Coordination and self-assembly in the crystal structure of K[AsMe2S2] · 2H2O

A major feature of the crystal structure of K[AsMe2S2]. 2H(2)O. which contains two independent formula units, is the presence of infinite sheets formed by edge sharing between two different types of K(H2O)(4)S-2 octahedra in which the sulfurs occupy either cis or ti ans positions. Although the four independent arsenic-sulfur distances all fall between those for single and double bonds, one sulfur at each arsenic is coordinated to potassium and the As-S distance here is longer [mean 2.140(2) Angstrom] than that to the second sulfur [mean 2.111(5) Angstrom] which is effectively free. The structure also contains a series of weak O-H ... S hydrogen bonds.