Lanthanide higher oxides

Lanthanide Higher Oxides The Contributions of Leroy Eyring... 

In this article I will elaborate on the knowledge, which was obtained by Professor Leroy Eyring and his colleagues in more than 50 years of research on the lanthanide higher oxides and their ideas for the applications of these oxides. Also the unique non-stoichiometric characteristics of the lanthanide higher oxides are emphasized and the intrinsic relationship between the macroscopic properties and nano-scale structures is demonstrated. 

TABLE 1 Summary of the oxygen-deficient fluorite-related lanthanide higher oxides of the Rn02n-2m series... 

Establishment of the structures of the lanthanide higher oxides, finding the structural principles involved, and attempts at understanding the relationship between their structures and properties have been under way for five decades. 

Based on the fluorite-type module theory the thermodynamic properties, hysteresis, and reactions between the homologous series can be elucidated and the structures of homologous series experimentally discovered may be modeled. Using these principles a wide range of non-stoichiometric ternary lanthanide higher oxides from RO2 to R2O3 were founded. 

The striking characteristics of the lanthanide higher oxides are rooted in the electronic structure of Ce, Pr, and Tb atoms. The lanthanide elements located in the third group of the periodic table have a normal 3+ valence state and the normal oxides have the R2O3 formula. Due to the special electron configurations of Ce... 

Several review articles and books on the lanthanide higher oxides, which include thermodynamic properties, have been published (Eyring, 1979 Haire and Eyring, 1994 Trovarelli, 2002 Adachi and Imanaka, 1998 Adachi et al., 2005). The systematic thermodynamic data of the cerium, praseodymium, and terbium oxides can be found in Bevan s and Eyring s papers (Hyde et al., 1966 Hyde and Eyring, 1965 Bevan and Kordis, 1964). 

FIGURE 17 A sketch of the oxygen content changes with temperature and oxygen partial pressure swings for the lanthanide higher oxides. 

Experimental electron diffraction data of the lanthanide higher oxides... 

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