Structure and vibrational spectra of argyrodite family compounds Cu8SiX6 (X = S, Se) and Cu8GeS6

Infrared transmission and Raman spectra of the argyrodite family compounds Cu8SiX6 (X = S,Se) and Cu8GeS6 have been measured. Structure data of Cu8SiSe6 and Cu8GeS6 at 300 K have been obtained through Rietveld analysis. On the basis of these results, the frequencies and intensities of infrared or Raman active modes of these compounds have been calculated, and the relations between the vibrational spectra and the crystal structures have been studied. (C) 1999 Elsevier Science B.V. All rights reserved.