Electrochemical Preparation and Structural Characterization of La2NiO4+δ Phases (0 ≤ δ ≤ 0.25)

摘要: Abstract Electrochemical oxidation in alkaline solution has been used to control and extend the oxygen overstoichiometry of La 2 NiO 4+δ phases (0 ≤ δ 0.25). Chemical analysis carried out determine nickel (III) content related excess. Structural data (X-ray powder diffraction on neutron 4.25 ) show that interstitial atoms are introduced into O layers. ESR spectra for compound recorded at 4.2 298 K characterize either low spin Ni 3+ ( t 6 2g d 1 x - y a flattened octahedral site or + τ an elongated octahedron. The results relaxation structure as function could arise from steric effect (i.e., formation disproportionation 2+ .