We found that two lithium niobate-type oxides, CdPbO3 and PbNiO3 were synthesized by high-pressure as metastable low-pressure perovskite-type phases. We then discussed the stability of lithium niobate-type and perovskite-type oxides relative to oxides with other structure for ABO3 compounds. Consequently, the tolerance factor of perovskite is not the only predominant one to determine the stabil...

The properties of transition-metal oxides are related to the presence of elements with mixed valences, such as Mn and Co. Spatial mapping of the valence-state distribution of transition-metal elements is a challenge to existing microscopy techniques. In this letter, using the valence-state information provided by the white lines observed in electron energy-loss spectroscopy in a transmission el...