This Book is basically aimed at synthesis, solid state reactivity, crystallographic characterization and electrical measurements on titania and zirconia based ceramic materials, which have been identified as potential matrix for process development in technology of radioactive waste management. Though their applications in this area are well documented but their structure–property relationship is not yet investigated to the desired level, therefore, it is necessary to understand thoroughly the structural complexities of the interactions of the effluent cations vis-a-vis ceramic precursors. Powder diffraction data and GSAS software based calculations of cell parameters, crystal symmetry, isotropic and thermal parameters, inter-atomic distances and other structural factors provide a good data base for process development. The electrical properties of substituted ceramic phases have been investigated with a view to find their applications in electrical and electronic materials, insulators and sensor technology. Impedance spectroscopy is used as a prime technique for such investigations.