The chemical compound LaCoO₃ can only be obtained by high-temperature sintering of a mixture of lanthanum and cobalt oxides according to the reaction: La2O3 + 2CoO + 1/2O2 = 2LaCoO3 It does not matter how the initial oxides La2O3 and CoO were obtained. You can simply mix purchased oxides or obtain them by decomposing the corresponding nitrates. In any case, you cannot do without sintering, since with the thermal decomposition of a stoichiometric mixture of nitrates you will not obtain the compound LaCoO3, but a mixture of individual oxides of cobalt and lanthanum.

Hi Ankit Vishwakarma

Actually it's likely that you may succeed by this route. I have no direct experience in making lanthanide cobaltates, but with my colleagues at IBM we made lanthanide cuprates by spray pyrolysis of nitrate solutions during the last millenium.

See Article Bismuth Strontium Calcium Copper Oxide High-Tc Superconducti...

Article YBa2YCu3O7–δ Thin Films Grown by a Simple Spray Deposition Technique

Article Spray pyrolysis for high Tc superconductor films

Article Comparative analysis of YBCO thin films prepared by spray-py...

(The last two articles are reviews quoting our work.)

It should be easier to make Co(3+) compounds than Cu(3+) compounds, and Co(3+) oxide is more acidic than Cu(3+) oxide (which should help with the absence of a strongly basic oxide - we had BaO or SrO in our compounds back then). The nitrate precursors help ensure a strongly oxidizing environment. Still, an oxygen atmosphere may be needed if you want a stoichiometric cobaltate.