Synthesis and Characterization of the Thiogermanic Acids H4Ge4S10 and H2Ge4S9

Abstract

The synthesis and structure of the thiogermanic acids H 4 Ge 4 S 1 0 and H 2 Ge 4 S 9 are reported. A novel preparation method consisting of reacting germanium oxide with liquid hydrogen sulfide containing a trace amount of water is used to form Ge 4 S 1 0 4- ions. Evaporating the hydrogen sulfide solution at room temperature leaves an unstable H 4 Ge 4 S 1 0 .xH 2 O product. The stoichiometry and structure of the thermally stable anhydrous phase are dependent on reaction time. An H 4 Ge 4 S 1 0 product with an adamantane-like cage structure is obtained at shorter reaction times. Longer reaction times produce an H 2 Ge 4 S 9 product with a more complex cage unit, a higher symmetry unit cell, and increased thermal stability. Raman, infrared, powder X-ray diffraction, and thermogravimetric data are reported for both structures.