Fluorite structure oxides

Structure and Oxygen Diffusion in Fluorite Structure Oxides... 

For a simple solid solution the lattice parameter usually follow Vegard s rule with good approximation, i.e. a linear relationship exists between lattice parameter and the concentration of the solute. The slope of this straight line is termed Vegard s slope, Kim published an empirical relation between ionic radius of the metal ion of oxides (dopants) dissolved in ceria (and other fluorite structured oxides)... 

Numerous other anion-deficient fluorite-structured oxides have been investigated,... 

The fluorite structure has a large number of octahedral interstitial voids. Thus this structure is rather open and rapid ion diffusion might be expected. A high temperature modification of zirconia has the fluorite-type structure, which is stabilized by addition of trivalent or divalent cations, such as Ca and Y, while pure ceria adopts the fluorite structure. Oxide ion conduction is... 

In addition to fluorite structure electrolytes such as stabilised zirconia and ceria, there are many non-fluorite structure oxides which are potentially attractive for SOFC electrolyte application. These include perovskites like lanthanum gallate and to a lesser degree calcium titanate. Alternative oxides are the pyrochlores such as yttrium zirconate (YZr207)and gadolinium titanate (Gd2Ti207) [49,50], but these are only suitable in very limited oxygen pressure ranges. Therefore, the main discussion here focuses on the perovskites. 

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