A novel bifunctional thioarsenate based on unprecedented molecular [Cd4As8Se16(Se2)2]8− cluster anions.

Exploring and developing new functional inorganic chalcogenides with unique structures is always one of the most important missions in solid-state chemistry, especially those with molecular structures. Herein, a novel quaternary thioarsenate, Cs2CdAsSe5, is found to be based on an unprecedented molecular (poly)chalcogenide cluster architecture, which has never been discovered in inorganic chalcogenide systems. This rare windmill-like [Cd4As8Se16(Se2)2]8− cluster is made of four [CdSe4] and [As(V)Se4] tetrahedra via corner-sharing Se atoms and Se–Se bonds. Specifically, Cs2CdAsSe5 exhibits a remarkable photocurrent response and a large computationally predicted birefringence, and the origin of the optoelectronic performance and optical anisotropy is confirmed by detailed theoretical investigation. [ABSTRACT FROM AUTHOR]