Electron and X-Ray Diffraction, and 29Si MAS NMR Studies of the Solid Solution Cs4Sb4O8(Si4(1-)Ge4O12)

The solid solution Cs4Sb4O8(Si4(1-x)Ge4xO12) has been studied using electron and X-ray diffraction, and 29Si MAS NMR. All compositions for 0 ≤ x ≤ 1 were found to be single phase. However, the mmm symmetry of the X4O12 rings is maintained for x ≤ 0.15. Structure determinations from single crystals corresponding to x = 0.5 and 0.6 indicate a random distribution of Si (and Ge) atoms on the tetrahedral X sites. Analysis of the 29Si MAS NMR spectra shows that the statistical distribution of Si (and Ge) atoms in the X4O12 rings is equally present at a local level.