Investigations of the Structures of Chalcogenide Compounds

Jennifer A. Aitken, Kyoung-Shin Choi, Rhonda Patschke, and Mercouri G. Kanatzidis

Department of Chemistry, Michigan State University

Chalcogenide compounds are compounds which contain sulfur, selenium or tellurium. They are an important class of solid state compounds which have potential applications in thermoelectrics, non-linear optics, ferroelectrics, batteries and other areas. In our lab we are synthesizing new ternary and quaternary chalcogenides and determining their structure and properties. Chalcogenide compounds display a wonderful structural diversity, the properties of the compound can frequently be determined from the structure itself. Single crystal x-ray diffraction is utilized to determine the structure of each new compound. In some cases, we have discovered that there are chalcogen-chalcogen bonds in the structure which are visible via Raman spectroscopy, as shown in the figure below. The local structure surrounding the chalcogens leads to variations of the chalcogen-chalcogen vibrational mode between different compounds. From the Raman spectra we can not only verify the presence of a chalcogen-chalcogen bond but also determine a relationship between the shift in the wave number of the chalcogen-chalcogen stretching mode and the local geometry in the structure.