The Raman and Infrared Spectra and the Structures of Dimethyl Dichalcogenides

Abstract

There are six possible configurations for CH₃-X-X-CH₃ (X=0, S, Se, Te); D_3d, D_3h, C_2h, C_2v, C₂ and C₁. So the structures of molecules of the type CH₃-X-X-CH₃ have been the subject of several investigations. It has been reported that CH₃-X-X-CH₃ type molecules had a skewed structure with C₂ symmetry or a cis form with C_2v symmetry. However the obtained vibrational spectra show the general simplicity of the spectra and the lack of coincidence between Raman and infrared frequencies which indicates that a molecule has a center of symmetry. Therefore a C₂ structure or a C_2v symmetry can not be supported for CH₃-X-X-CH₃ type molecules. The present object of the vibrational study is to distinguish between the six most probable structures.

Key Words:

• Raman, Infrared
• Structure
• CH₃-O-O-CH₃
• CH₃-S-S-CH₃
• CH₃-Se-Se-CH₃
• CH₃-Te-Te-CH₃