Preparation and Properties of Perovskite-Type Oxides from Three-Dimensional Heterometal Assemblies, {Ln[Cr(ox)₃]⋅10H₂O}_<i>x</i> (Ln=La, Pr or Nd)

Abstract

Three kinds of heterometal assemblies, {Ln[Cr(ox)3]• 10H2O}x (Ln=La, Pr or Nd), were prepared by the reaction of K3[Cr(ox)3]• 3H2O with Ln(NO3)3• 6H2O in

Synthesis ofAFeO2.5+x(0≤x≤0.5;A=Sr, Ca) Mixed Oxides from the Oxidative Thermal Decomposition ofA[Fe(CN)5NO]·4H2O

“…The synthesis of mixed oxides, particularly perovskites and related oxides, from the decomposition of inorganic coordination compounds allows one to lower the reaction temperature and to obtain more homogeneous and finely divided powders (1)(2)(3)(4)(5).…”

Thermal evolution of the microstructure of nanosized LaFeO3 powders from the thermal decomposition of a heteronuclear complex, La[Fe(CN)6] · 5H2O

“…14 The development of innovative processing methods through chemistry permits one to lower the preparation temperature and to improve homogeneity and reproducibility of the ceramic products, with the synthesis of ultrafine and chemically pure powders of mixed-metal oxides at low temperatures. [23][24][25][26][27] Moreover, this method permits one to obtain the trimetallic complexes as a single phase, the decomposition of which leads to the formation of the single phase of trimetallic perovskite-type oxides, containing either two Ln and one Me, [28][29][30] or one Ln and two Me. [16][17][18][19][20][21] The preparation of LnMeO 3 perovskite-type oxides by the thermal decomposition at low temperatures from the corresponding heteronuclear complexes, which are readily precipitated from aqueous solution, has been first proposed by Gallagher in 1968.…”

A temperature-dependent powder diffraction study of chromium lanthanum nitrate, LaCr(NO3)6·12H2O

“…This intramolecular oxidation reaction is certainly due to the in situ oxygen formation inside the solid during this stage. Indeed, as already described in the course of the decomposition of mixed chromium lanthanum oxalates (Sakamoto et al, 1992) and citrates (Devi and Rao, 1993), chromium(III) oxidation is only observed in oxidizing atmospheres. The subsequent reduction of LaCrO 4 to LaCrO 3 at higher temperature depends on the oxygen pressure inside the reaction vessel.…”

“…The subsequent reduction of LaCrO 4 to LaCrO 3 at higher temperature depends on the oxygen pressure inside the reaction vessel. It is clear that, in vacuum or in nitrogen, the low oxygen pressure involves the reduction of LaCrO 4 at a lower temperature than that observed in an ambient oxygen pressure atmosphere (Sakamoto et al, 1992;Devi and Rao, 1989;Bueno et al, 1995;Furusaki, 1997). It is interesting to note that, to our knowledge, it is the second example of synthesis of a nitrato-complex of lanthanum with a trivalent cation, and also of a nitrate compound in which a double valence change of a cation is reported.…”