Inorganic Frameworks from Selenidotetrelate Anions [T2Se6]4- (T ) Ge,Sn): Synthesis, Structures, and Ionic Conductivity of [K2(H2O)3][MnGe4Se10] and (NMe4)2[MSn4Se10] (M ) Mn, Fe)

Syntheses, structures, and physical properties of three inorganic framework compounds [K2(H2O)3][MnGe4Se10] (1), (NMe4)2[MnSn4Se10] (2), and (NMe4)2[FeSn4Se10] (3) are presented. The title compounds are based on a prominent open framework anionic structure; in these cases, however, they contain K+, the smallest type of counterion to be included so far (1), or represent Sn analogues (2, 3). Both changes with respect to related compounds are reflected in peculiar physical properties, such as ion conductivity or relatively small band gaps