Sodalites of the composition Cd-8[BeSiO4](6)X(2), X = S, Se, and Te, have been synthesized by hydrothermal reaction of CdO, BeO, SiO2, and X at 750 degrees C and 2 kbar. The materials crystallize with the cubic sodalite unit cell with an ordered Be/Si framework in the space group . Their structures have been refined from powder diffraction data in order to delineate the dimensions of the Cd(4)X units in the sodalite cage and the intercage separation of these units. Infrared, UV-vis and Si-29 MAS NMR spectra of these materials are also reported. Correlations between structural parameters and Si-29 chemical shifts have been determined for this series of compounds. UV-vis data demonstrate that the Cd(4)X units do not interact electronically.