Thermodynamical Stability of the Nickel-Lanthanum Complex Oxides

Thermodynamic analysis of the ternary La–Ni–O system

“…The absence of visible variation of the unit cell parameters of La 2 NiO 4 with the La/Ni ratio in the range 1.925-1.99 seems to exclude the possibility of a solid solution of NiO in La 2 NiO 4 at least for air-annealed compounds in agreement with Foëx et al [39]. Recently, Bannikov and Cherepanov (the same group as in [49,36]) reported the synthesis and investigation of the thermodynamic stability of La 4 Ni 3 O 10 , La 3 Ni 2 O 7 , and LaNiO 3 [31]. Thus, the existence of La 2 NiO 4 , La 3 Ni 2 O 7 , La 4 Ni 3 O 10 , and LaNiO 3 as thermodynamically stable phases in air in the vertical section La 2 NiO 4 -LaNiO 3 is now well established.…”

“…The decomposition of LaNiO 3 at elevated temperatures is described in several publications [12,15,[31][32][33][34][35], partially with rather conflicting results concerning the stability range and decomposition products ( Table 2). The temperature of the reaction (1) in air has been measured as 1120 K [15], 1367 K [32], and 1253 K [31].…”

Phase Equilibria and Crystal Structures of Mixed Oxides in the La-Mn-Ni-O System

“…This influences both the stability limits of similar phases and their defect structure. In particular, the average oxidation state of Mn ions in LaMnO 3 + δ in air is slightly higher than 3+, that of Co ions in LaëÓO 3 -δ is slightly lower than 3+, the oxygen-defi- [22,23].…”

“…Under these conditions, the Mn-Ni-O system contains Mn 3 O 4 -and NiO-based solid solutions: [9]. The La-Ni-O system in air at 1100 ° C contains three perovskite-like phases: La 2 NiO 4 , La 3 Ni 2 O 7 , and La 4 Ni 3 O 10 [10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Two more mixed oxides in this system were obtained under other conditions: LaNiO 3 (below 900 ° C in air or at elevated oxygen pressures [22][23][24][25][26]) and La 6 Ni 5 O 15 (at 1200 ° C in…”

Oxide material synthesis by combustion of organic-inorganic compositions

“…Such instances may be the synthesis of LaNiO 3 [34][35][36], BiFeO 3 [20,[37][38][39]. In the source-oxide synthesis of LaNiO 3 and BiFeO 3 , as noted in [20,34], the acceptable process rate is achieved at temperatures exceeding the thermal stability interval of these compounds.…”