Synthesis and Characterization of the Thiogermanic Acids H4Ge4S10 and H2Ge4S9

The synthesis and structure of the thiogermanic acids H4Ge4S10 and H2Ge4S9 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 Ge4S104ions. Evaporating the hydrogen sulfide solution at room temperature leaves an unstable H4Ge4S10·xH2O product. The stoichiometry and structure of the thermally stable anhydrous phase are dependent on reaction time. An H4Ge4S10 product with an adamantane-like cage structure is obtained at shorter reaction times. Longer reaction times produce an H2Ge4S9 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. Disciplines Materials Science and Engineering | Physical Chemistry Comments Reprinted with permission from Journal of Physical Chemistry B 107 (2003): 5413–5418, doi:10.1021/ jp027313w. Copyright 2003 American Chemical Society. This article is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/mse_pubs/73 Synthesis and Characterization of the Thiogermanic Acids H4Ge4S10 and H2Ge4S9 Steven A. Poling, Carly R. Nelson, Jacob T. Sutherland, and Steve W. Martin* Department of Materials Science and Engineering, Iowa State UniVersity, Ames, Iowa 50011 ReceiVed: October 25, 2002; In Final Form: December 23, 2002 The synthesis and structure of the thiogermanic acids H4Ge4S10 and H2Ge4S9 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 Ge4S10 ions. Evaporating the hydrogen sulfide solution at room temperature leaves an unstable H4Ge4S10‚xH2O product. The stoichiometry and structure of the thermally stable anhydrous phase are dependent on reaction time. An H4Ge4S10 product with an adamantane-like cage structure is obtained at shorter reaction times. Longer reaction times produce an H2Ge4S9 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.