PREPARATION AND CRYSTAL-STRUCTURE OF THE CESIUM SELENIDOGERMANATES(IV) CS4GE4SE10-CENTER-DOT-2CH(3)OH AND CS4GE2SE8

Methanolothermal reaction of Cs2CO3 with Ge and Se at 190 degrees C yields Cs4Ge4Se10.2CH(3)OH and Cs4Ge2Se8, the structures of which have been determined by X-ray structural analysis. The anion [Ge4Se10](4-) in Cs4Ge4Se10.2CH(3)OH displays an adamantane-like structure in which four GeSe4 tetrahedra are linked via joint vertices. In contrast Cs4Ge2Se8 contains the novel dinuclear anion [Ge2Se8](4-), the first example of a selenidogermanate(IV) exhibiting Se-2 bridging units. Two GeSe4 tetrahedra are linked in this anion through Se-Se bonds to yield a six-membered ring, which displays a chair conformation and crystallographic C-2h symmetry.