A complex oxalate precursor, CaCu3(TiO)4(C2O4)8·9H2O, (CCT-OX), was synthesized and the precipitate that obtained was confirmed to be monophasic by the wet chemical analyses,
X-ray diffraction, FTIR absorption and TG/DTA analyses. The thermal decomposition of this oxalate precursor led to the formation
of phase-pure calcium copper titanate, CaCu3Ti4O12, (CCTO) at ≥680°C. The bright-field TEM micrographs revealed that the size of the as synthesized crystallites to be in the
30–80 nm range. The powders so obtained had excellent sinterability resulting in high density ceramics which exhibited giant
dielectric constants upto 40000 (1 kHz) at 25°C, accompanied by low dielectric losses, <0.07.