Reactivity in molten oxonitrates of lanthanum and maganese salts. Synthesis of La_(l-x)MnO_3

摘要

The reactivity of each lanthanum and manganese nitrate and chloride is studied in four molten media, NaNO_3, NaNO_2, KNO_3 and KNO_2 at 500 °C. The lanthanum salts produce mainly hydroxide and oxychloride. The manganese salts give a variety of compounds, mainly oxides and also oxychloride and sodium manganate. The reaction of the mixed metal salts leads to the perovskite non-stoichiometric La_(l-x)MnO_3. The results can be interpreted in terms of acido-basicity of the lanthanum ion and of oxidation pathway of the manganese species. The simultaneous presence of both metal ions in the media forces La_(l-x)MnO_3 to precipitate. The obtained crystallites are nanosized with a large surface area.