Preparation of LaNiO3 powder from coprecipitated lanthanum-nickel oxalates

Article abstract of DOI:10.1007/BF01045351

Coprecipitation of lanthanum and nickel oxalates in a water-alcohol mixed solution of an oxalic acid resulted in a simultaneous and homogeneous deposition of the respective oxalate particles with a desired cation ratio. The coprecipitated oxalate could be readily converted to a fine powder (5 to 6 m² g^-1) of LaNiO₃ by heating at 800 to 850° C. Examination of precipitation conditions established an optimum procedure for the powder synthesis of LaNiO₃. Thermal analysis showed that La₂NiO₄ (high temperature form) is transiently produced prior to the formation of LaNiO₃. Mixed valency of the nickel ion was quantitatively determined by means of the oxidation-reduction titration, suggesting that the chemical formula of the powders might be LaNiO_{2.85 to 2.90}.