Structures of the individual iron oxides

The planets nearest the Sun have a high-temperature surface while those further away have a low temperature. The temperature depends on the closeness to the Sun, but it also depends on the chemical composition and zone structures of the individual planets and their sizes. In this respect Earth is a somewhat peculiar planet, we do not know whether it is unique or not in that its core has remained very hot, mainly due to gravitic compression and radioactive decay of some unstable isotopes, and loss of core heat has been restricted by a poorly conducting mainly oxide mantle. This heat still contributes very considerably to the overall temperature of the Earth s surface. The hot core, some of it solid, is composed of metals, mainly iron, while the mantle is largely of molten oxidic rocks until the thin surface of solid rocks of many different compositions, such as silicates, sulfides and carbonates, occurs. This is usually called the crust, below the oceans, and forms the continents of today. Water and the atmosphere are reached in further outward succession. We shall describe the relevant chemistry in more detail later here, we are concerned first with the temperature gradient from the interior to the surface (Figure 1.2). The Earth s surface, i.e. the crust, the sea and the atmosphere, is of... 

In the present, work we propose the preparation of Y-Fez03-Si02 nanocomposite through individual sols of iron oxide and SiOz. This approach provides wide possibilities to control the structure of the composite [3]. Structural features and magnetic properties of the samples are reported. 

Oxidation. Catalyst preparation procedures determine catalyst structures and consequent catalytic performance. The activity of combinations of oxides is often quite different from those of the individual oxides. For example, the capability of FejOj, the catalyst used to oxidize CH3OH to formaldehyde, to promote complete oxidation is nearly absent in iron(III) molybdate, Fe2(Mo04>3. ... 

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