A Novel synthesis method based on the behaviour and effect of the addition of chloride and sulphate for spheroidization of the structure of rare earth-oxide e.g. and were prepared from combustion synthesis at a temperature of. The compounds were later doped with at various percentages and calcined at for 4 hours. The crystallites size and the thermal stability of the doped powder were determined with X-ray and thermogravimetry respectively. Scanning Electron Microscopy was finally used to determine the morphology of the novel rare earth-oxides calcined at. Secondly, another set of doped compound were also calcined at a various temperatures for 4 hours and its crystallites size, thermal stability and morphology were also determined with X-ray, Thermogravimetry and Scanning Electron Microscopy. Finally, conclusion was drawn based on how the crystallites size changed with regard to percentage of at the calcinations temperature of and also at a various calcination temperatures with a fixed percentage of the doped. Lastly, the same techniques were applied to gadolinium oxide.