SYNTHETIC PEROVSKITE OXIDES

Storage of chemicals, 385 Strained-ring compounds, 385 Styrene—butadiene rubber, 386 Sugars, 386 Sulfinyl azides, 387 Sulfonation incidents, 387 Sulfonic acid esters, 388 Sulfonyl azides, 388 Sulfur black, 389 Sulfur compounds, 389 Sulfur esters, 389 Sunspots, 390 Superheated liquids, 390 Superiors/supervisors, 390 Synthetic perovskite oxides, 391... 

From a practical point of view, these compounds are models of crystalline matrices for nuclear waste disposal. One such storage material is SYNROC, a synthetic mineral whose major constituents are the complex oxides hollandite, zirconolite, and perovskite. We have chosen perovskite as a model structural family because of its efficient packing and its accommodation of a wide range of cations, both in size and oxidation state (5). 

Lanthanides as components in complex oxide systems In perovskites For conduction in electrocatalysis For oxidizing properties For hydrogenation properties For synthetic gas (CO-H2) reactions To provide sulfur oxides (SO, ) control In oxysulphides In other systems ... 

In a much later stage of development, other ceramics that were not clay-or silicate-based depended on much more sophisticated raw materials, such as binary oxides, carbides, perovskites, and even completely synthetic materials for which there are no natural equivalents. The microstructures of these modern ceramics were at least an order of magnitude finer and more homogeneous and much less porous than those of their traditional counterparts. It is the latter — the modern or technical ceramics — with which this book is mainly concerned. 

Li-an Yu. Lu Jin, Min-fang Han,First-principles Study on Electronic Structures and Oxygen Vacancy Energies of Perovskite-type Oxides BaB03-5( B = Te,Co,Nb),Journal of Synthetic Crystals, 41(3),747-752(2012). 

To explain the effect of water on the location of chlorine at the surface of the catalyst, a combined time-of-flight-secondary ion mass spectrometry and X-ray photoelectron spectroscopy study has been carried out fresh and used LaMn03+5 catalysts [60]. Both techniques indicated that the presence of chlorine on the tested catalysts increased by exposure of the catalyst to the reactive mixture in dry synthetic air. Chlorine was present as both chloride ion and covalent chlorine on perovskite, while organic chlorinated residues were absent. The lanthanum excess as oxide (hydroxide) partially covering the perovskite mainly transforms into LaOCl and to a minor extent into Lads. Water delays the surface degradation extent of the perovskite into related (oxy) (hydroxy) chlorinated inorganic phases by less molecular chlorine and related chlorine species on the catalyst surface. Equations (17.4)-(17.6) describe the reaction scheme of Cl removal over the investigated perovskite and the role of water. 

There has been a recent drive to develop low-temperature, environmentally friendly synthetic routes to metal oxide nanoparticles. In 2006, Brutchey and Morse reported the template-free synthesis of BaTiOs perovskite nanoparticles of uniform size and shape at only 16 °C. This synthesis is described as a vapour-diffusion sol-gel route, whereby the slow hydrolysis of a bimetallic precursor is achieved yia the kinetically-controlled delivery of water, according to equation 2 °... 

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