Reinvestigation of Ge4Se9 based on single-crystal data

Tetragermanium nonaselenide, Ge4Se9, adopts a two-dimensional layered structure. The layer is made up of infinite chains of corner-sharing GeSe4 tetrahedra and the chains are connected via the Ge2Se7 unit to form the two-dimensional layer. These layers are stacked to form the three-dimensional structure with a van der Waals gap. A previous structure report on Ge4Se9 based on powder diffraction data [Fjellvåg, Kongshaug & Stølen (2001). J. Chem. Soc. Dalton Trans. pp. 1043-1045] is comparable with our results except for the absolute structure determination.