International audienceThe multiferroic LuFeO was recently proposed as a promising material for oxygen storage due to its easy reversible oxidation into LuFeO. We have investigated the similar scenario in YbFeO, leading to a slightly greater oxygen storage (OSC) capacity of 1434 μmol O/g. For the first time, the structural model of LnFeO was fully understood by high-resolution microscopy images, and synchrotron and neutron diffraction experiments, as well as maximum entropy method. The oxygen uptake promotes a reconstructive shearing of the [YbO] sub-units controlled by the adaptive Ln/Fe oxygen coordination and the Fe redox. After oxidation, the rearrangement of the Fe coordination polyhedra is unique such that all available FeO units (n = ...