Cadmium is an extremely toxic nonbiodegradable heavy metal, which accumulates in significant quantities in the near-surface environments, where it easily enters surrounding water and soil. In this work, we synthesized a series of cadmium silicates (CdAl2Si2O8, Cd2SiO4, Cd3Si3O9, Cd3(SiO4)O), which are prospective materials for cadmium immobilization. The most environmentally stable and least studied of them, CdAl2Si2O8, was investigated by means of scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder and single crystal X-ray diffraction (over the temperature range of 27–1100 °C). Using alkali cations additives, we were able to obtain CdAl2Si2O8 at a temperature (500 °C) half previously reported. We showed that cadmium can be successfully incorporated into a feldspar-like crystal structure and that the amount of cadmium could range depending on synthesis conditions from 21 to 37 wt % CdO. Our data indicate that CdAl2Si2O8 is stable up to at least 1100 °C and does not undergo phase transitions with a change in the volume of the unit cell. We can conclude that CdAl2Si2O8 is a promising material for cadmium immobilization, given its resistance to leaching and low synthesis temperatures.