Three new thiogermanates, (trenH2)2[Ge2S6] (1, tren = tris(2-aminoethyl)amine), [Eu(dien)3]2[Ge2S6]Cl2 (2, dien = diethylenetriamine) and [Y2(tepa)2(μ-OH)2(μ-Ge2S6)](tepa)0.5·H2O (3, tepa = tetraethylenepent-amine), were solvothermally synthesized and characterized. Both 1 and 2 are composed of discrete [Ge2S6]4− anions, while 3 contains a bridging [Ge2S6]4− anion as a μ2-ligand with trans terminal S atoms linking [Y2(OH)2(tepa)2]4+ groups, which is the only example of germanium chalcogenide anions acting as bridging ligands to a lanthanide complex ion. The optical absorption spectra indicate that they are wide band-gap semiconductors and their thermal stabilities have been investigated by thermogravimetric analyses (TGA).
![Graphical abstract: Solvothermal synthesis, crystal structures and properties of three new thiogermanates: the only example of the thiogermanate anion [Ge2S6]4− as a bridging ligand to a lanthanide complex ion](http://hg.y866.cn/compound/lib/scimg/usr/1/C2CE25082A.jpg)
