Three new ordering schemes for oxygen vacancies in CaMnO3–x superlattices based on square-pyramidal co-ordination of Mn3+

Electron diffraction and high resolution electron microscopy have brought to light three new ordered structures in a material of composition CaMnO(2.50 ± 0.02); in all these structures as well as in another analogous oxide, CaMnO2.75, the original features of the perovskite structure are preserved, thus offering an explanation for the facile loss and uptake of oxygen properties that these selective oxidation catalysts possess.