Solventothermal Synthesis and Structure of the Polymeric thioarsenates(III) (Et4N)(2)As6S10 and (Et4N)(2)AS(8)S(13)

Reaction of (Et4N)Cl with As2S3 and Na2S in acetonitrile at 110 degrees C a ffords the polymeric thioarsenate(III) (Et4N)(2)As6S10 in which the cyclic [AS(3)S(6)](3-) and chainlike [As3S7](5-) trinuclear molecular building uni ts are linked together through common sulphur atoms into infinite double ch ains. In contrast, reaction of the same starting materials at higher temper atures (180 degrees C) in water leads to formation of a markedly denser pha se (Et4N)(2)As8S13, whose thioarsenate(III) (1)(infinity)[As8S132-] anions exhibit a higher condensation grade. These likewise double chains are compo sed of cyclic [As3S6](3-) and dinuclear [As2S5](4-) units with shared psi-A sS3 tetrahedra corners. Analogous treatment of (Et4N)Cl with As2Se3 and Na2 Se in acetonitrile (T = 110 degrees C) yields (Et4N)[SeAsSe7].