Oxygen cavity

Tihe presence of exchangeable cations, framework oxygens, cavities of A different sizes, and previously adsorbed water molecules makes the interaction of water with zeolites complicated (1). As a result, in zeolites, water molecules with different physical properties exist, from tightly bound to liquid-like water. This was shown by NMR measurements (2,3 4) ... 

A site cation in perovskites B site cation in perovskites Oxygen cavity in cluster-like systems Carbonate... 

The decomposition of the nitrates produces oxygen molecules, and we have verified that if a mixture of silver nitrates and closed tubes is submitted to a thermal treatment (400°C) decomposing the salt, it is possible to observe filled CNTs (Ag, Co, Cu [34]). It appears that oxygen liberated during the thermal decomposition of the metal salt erodes the CNT tip and the yet un-decomposed salt then enters by capillarity (see Fig. 8). We have also observed during the electron-irradiation decomposition of enclosed nitrate that the liberated gases erodes the CNT cavity [22] (see the innermost tubes in Fig. 5). 

In these ions the heteroatoms are situated inside cavities or baskets formed by MOg octahedra of the parent M atoms and are bonded to oxygen atoms of the adjacent MOg octahedra. The stereochemistry of the heteroatom is determined by the shape of the cavity which in turn depends on the ratio of the number of heteroatoms to parent atoms. Three major and a number of minor classes are found. 

Analysis of weight loss isotherms displayed in Fig. 8 shows that the first step in the interaction between Nb02F and carbonates of other alkali metals is similar to the interaction described by Equation (11). However, compounds of the M(Nb04F form, where M = Na, K, Rb, Cs, were not found [85]. The instability of such compounds is related to the ionic radii of the alkali metals, which are greater than that of Nb5+, thus the ions are too large to occupy the octahedral cavities formed by the oxygen and fluorine ions. 

The cavity is further bounded by two carbon atoms and an adjacent hydrogen atom of each of six of the hydroquinone molecules in the manner shown in the figure. Hence, the wall of the cavity is formed by 12 oxygen atoms, 12 carbon atoms, and 18... 

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