Hydrothermal Studies in the System Hg/Se/Te/O: The First Te-IV/Se-VI Oxocompounds Hg3SeTe2O10 and Hg3SeTe4O14, and the Mixed-valent Hg5Se2O8

摘要

Reactions of Hg-II-, Te-IV-, and Se-VI-containing starting materials under moderate hydrothermal conditions (230 degrees C, one week) resulted in the formation of the mercuric oxotellurate(IV)/oxoselenate(VI) phases Hg3SeTe2O10 and Hg3SeTe4O14. The mixed-valent phase Hg5Se2O8 containing mercury in oxidation states +I and +II as well as selenium in oxidation states +IV and +VI also formed under these conditions. The crystal structures of the three compounds were determined from single-crystal X-ray data. All structures contain building blocks characteristic for Hg-I or Hg-II cations and for oxochalcogenate anions of Se-IV, Se-VI, or Te-IV. Whereas the oxoselenate(VI) and oxotellurate(IV) anions are isolated in the structure of Hg3SeTe2O10, the higher TeO2 content in the structure of Hg3SeTe4O14 leads to a condensation of the corresponding anions. The crystal structure of Hg5Se2O8 is described in terms of oxo-centered [OHg4] tetrahedra.