Several variants of hydrated sodium cadmium bisulfate, Na 2Cd2(SO4)3·3H2O, Na2Cd(SO4)2·2H2O, and Na 2Cd(SO4)2·4H2O have been synthesized, and their thermal properties followed by phase transitions have been invesigated. The formation of these phases depends on the stochiometry and the time taken for crystallization from water. Na2Cd 2(SO4)3·3H2O, which crystallizes in the trigonal system, space group P3c, is grown from the aqueous solution in about four weeks. The kröhnkite type mineral Na 2Cd(SO4)2·2H2O and the mineral astrakhanite, also known as blödite, Na2Cd(SO 4)2·4H2O, crystallize concomittantly in about 24 weeks. Both these minerals belong to the monoclinic system (space group P21/c). Na2Cd2(SO4) 3·3H2O loses water completely when heated to 250 °C and transforms to a dehydrated phase (cubic system, space group I4̄3d) whose structure has been established using ab initio powder diffration techniques. Na2Cd(SO4)2· 2H2O transforms to α-Na2Cd(SO4) 2 (space group C2/c) on heating to 150 °C which is a known high ionic conductor and remains intact over prolonged periods of exposure to moisture (over six months). However, when α-Na2Cd(SO 4)2 is heated to 570 °C followed by sudden quenching in liquid nitrogen β-Na2Cd(SO4)2 (P2 1/c) is formed. β-Na2Cd(SO4)2 takes up water from the atmosphere and gets converted completely to the kröhnkite type mineral in about four weeks. Further, β-Na 2Cd(SO4)2 has a conductivity behavior comparable to the α-form up to 280 °C, the temperature required for the transformation of the β- to α-form. These experiments demonstrate the possibility of utilizing the abundantly available mineral sources as precursors to design materials with special properties. © 2011 American Chemical Society.