Five Transition Metal-Mixed Germanium Chalcogenide Materials: Solvothermal Syntheses, Crystal Structures, Photoelectric Response Properties, and Ion-Exchange Properties

Germanium chalcogenides have attracted wide attention in inorganic chemistry because of their flexible structure and rich properties. Five new germanium chalcogenides containing transition metals such as manganese, zinc, and cadmium were synthesized by solvothermal methods using alkali metals as structural directing agents. Rb₂MnGeSe₄ (1), Cs₂MnGeSe₄ (2), and Cs₂ZnGeSe₄ (3) have a one-dimensional chain structure and Rb₂Zn₂GeSe₄·H₂O (4) and Rb₂CdGeSe₄ (5) have a two-dimensional layer structure. The electronic structure, band gap, and photocurrent response of compounds 1-5 have been comprehensively analyzed. Due to the two-dimensional layered structure of compounds 4 and 5, we studied their ion-exchange properties. Compounds 4 and 5 showed excellent ion-exchange properties and could be used as potential ion-exchange materials for the absorption of radioactive elements in nuclear wastewater.