Thermogravimetric investigations on A(H2O)6BX6 complexes and the formation of ABX6 and ABO3 structures

Thermogravimetry (TG) of A(H2O)6BX6 complexes are presented, with A = Cd2+, Co2+, Cu2+, Fe2+, Mg2+, Mn2+, Ni2+, Pb2+, Zn2+, B=Si4+, Sn4+, Ti4+, Zr4+, and X=Cl−, F−. On a selected number of complexes, differential thermal analyses (DTA) and differential scanning calorimetric measurements (DSC) have been performed. It was found possible to synthesize most complexes including Cd(H2O)6TiF6 as single crystals. The hexafluoride and the titanate compounds are formed from the corresponding cadmium hexaquo—hexafluoride complex. The cadmium titanate could be made either in the ilmenite or in the perovskite structure. The decomposition programs for the preparation of NiTiO3 and CdTiO3 are presented. The hexaquo—hexahalide complexes, in general, show one of two decomposition types. The intermediate product in one type is the metal(II) fluoride AX2 and in the other the mixed hexahalide compounds ABX6. Which type of decomposition occurs depends on the anion BX2−6.