Electron Microscopy of a Family of Hexagonal Perovskites: One-Dimensional Structures Related to Sr4Ni3O9

New stabilized phases in the Sr/Ca–Mn–Co–O system: structural–magnetic properties relationship

“…As previously observed in other related 1D oxides, bright dots can be associated to TP sites, whereas less bright dots along the c-axis should correspond to Oh sites. 27,28 Therefore, a careful analysis of the contrast variation along the c-axis leads to the polyhedra sequence along the polyhedra rows; according to that, the structure of these materials is formed by an ordered intergrowth between 3 unit cells of (Sr/Ca) 4 Mn 2 CoO 9 (-2Oh-TP-2Oh-TP-2Oh-TP-) and half a unit cell of (Sr/Ca) 3 MnCoO 6 (-Oh-TP-). Fig.…”

The hidden story in BaNiO3to BaNiO2transformation: adaptive structural series and NiO exsolution

“…During the moderate BaNiO3 reduction, several BaNiO3-x stoichiometries have been proposed, 9,10 culminating with a substoichiometric BaNi0.86O2.36 compound. 6 The later evidence and structural understanding in terms of composite structures of the A1+xNiO3 (A= Sr, Ni) series [11][12][13][14] helps to understand the BaNi5/6O5/2 oxide, first announced with supermixed valence +2,+3,+4 nickel. 13 This latter phase is considered as intermediate archetype during the structural transformation over the oxygen-evolution reaction (OER) redox cycling.…”

Low-dimensional magnetism in the mixed Cr valence spin-chain compound Sr_4Cr_3O_9

“…2(a), all the lines in the XRD pattern for our samples could be indexed using the closely related trigonal Sr 4 Ni 3 O 9 structure (Space group P 321, hexagonal lattice parameters a = 9.477 Å, and c = 7.826 Å) with 5 inequivalent Ni positions. 25,26 The overall structures of Sr 16 It should be pointed out that only the lattice parameters, the peak profile parameters, and the atomic positions of the Sr and Cr were varied in the fits. When the fractional occupancies and thermal parameters were varied, the fits did not converge.…”