Solventothermal Synthesis and Structure of the Polymerie Thioarsenates(III) (Et4N)2As6S10and (Et4N)2As8S13

Reaction of (Et4N)Cl with AS2S3and Na2S in acetonitrile at 110°C affords the polymeric thioarsenate(III) (Et4N)2As6S10in which the cyclic [As3S6]3-and chainlike [As3S7]5-trinuclear molecular building units are linked together through common sulphur atoms into infinite double chains. In contrast, reaction of the same starting materials at higher temperatures (180°C) in water leads to formation of a markedly denser phase (Et4N)2As8S13, whose thioarsenate(III) 1∞[As8S132-] anions exhibit a higher condensation grade. These likewise double chains are composed of cyclic [AS3S6]3-and dinuclear [As2Ss]4-units with shared ѱ-AsS3tetrahedra corners. Analogous treatment of (Et4N)Cl with As2Se3and Na2Se in acetonitrile (T =110°C) yields (Et4N)[SeAsSe7].