Effect of Cd2+Cd2+ on the growth and thermal properties of K2SO4 crystal

Single crystals of pure and Cd2+Cd2+-doped potassium sulfate were grown from aqueous solutions by the slow evaporation technique. From nutrient solutions with a CdSO4 concentration of 4 wt% crystals containing 0.014 wt% dopant concentration could be obtained. The X-ray diffraction patterns of powdered crystals confirmed their crystal structures for both cases. Thermal analysis of pure crystals shows that the αα–ββ phase transformation peak around 580 °C is superimposed with spurious effects, while for Cd2+Cd2+-doped crystals this is not the case. The thermal hysteresis of the phase transition is 8 K for undoped K2SO4 and is reduced to 3.5 K for K2SO4:Cd2+Cd2+. Compared to undoped crystals, the optical transmittance of Cd2+Cd2+-doped crystals is higher.