Oxygen site

Stabilization of the syn conformer in the gas phase is explained rather intuitively in terms of the extra stabilization due to increased interactions between the H atom in the OH group and the O atom in C=0 group. As one can see in Figure 5, the extra stabilization in the anti confonner in aqueous solution arises from the solvation energy, especially at the carbonyl oxygen site. 

Figure 2. The structure of 0.15 Li20 Mn02. The lithium and oxygen sites within the (2 X 2) channel of the a - MnO, framework are partially occupied.

Table I. The electrostatic energies of the central silicon site and one nearest-neighbor oxygen site for a 977 point-ion cluster, and the Madelung energies for silicon and oxygen in alpha-quartz...

Figure 9.18. Schematic picture ofthe different oxygen sites involved in the partial catalytic oxidation of propylene to acrolein on Bi2MoOg, along with their conceived role in the reaction...

La2 xSrxCu04 EFG tensor, disagrees with point charge model, charge state, holes from substitution of La by Sr are localized mainly at the oxygen sites in the CU-O2 plane... 

RBa2Cu40g (R = Sm, Y, Er) Nuclear-quadrupole coupling parameters at the rare-earth metal and copper sites from Cu ( Zn) and Ga( Zn) Mossbauer emission spectroscopy, EEG tensor in comparison with point charge model, shows that holes in lattices are localized primarily at chain-oxygen sites... 

U.S. EPA, Cost of In Situ Treatment of Fuel Oxygenate, Site Closure and the Total Cost of Cleanup, Conference on Remediation, National Ground Water Association, New Orleans, November 13-14, 2003. 

The FTIR data recorded upon N0/02 adsorption in the presence of C02 showed that bidentate carbonates were immediately formed along with nitrite species. By increasing the time of contact, carbonates were partially displaced, while nitrites evolved to nitrate species [52], Notably, the amounts of surface nitrites present at each contact time are lower in the presence of C02 than in its absence. This indicates that C02 competes for the surface oxygen sites able to give nitrites at the beginning of the adsorption process in fact, after several minutes of exposure to the N0/02/C02 mixture, the amount of nitrates stored was comparable to that obtained in the absence of C02. In conclusion, while in the presence of C02 the nitrite route is inhibited to some extent due to the competition between NO and C02 for the surface oxygen sites of the Ba phase, the nitrate route is only marginally affected by the C02 presence, if any. 

Figure 3 illustrates the resolution of two oxygen sites connected with Brpnsted protons [119] in HY zeolite. The separation of these sites from other, non-proto-nated positions in the zeolite framework was possible by a two-dimensional 1H-170 HETCOR (heteronuclear correlation) NMR experiment which was acquired at... 

Nickel oxide, NiO, which adopts the sodium chloride structure (Fig. 1.14), can readily be made slightly oxygen rich, and, because the solid then contains more oxygen than nickel, the crystal must also contain a population of point defects. This situation can formally be considered as a reaction of oxygen gas with stoichiometric NiO, and the simplest assumption is to suppose that the extra oxygen extends the crystal by adding extra oxygen sites. Atoms are added as neutral atoms, and... 

These equations may be summarized as follows, but the intermediate stages involving the non-bridging oxygen sites are of crucial importance, as demonstrated by the observed resistance of vitreous silica to aqueous attack ... 

This hypothesis was tested using DMSO (5) to limit both proton and water exchange whereupon the 170 signals of the four oxygen sites in the [Re0(H20)(CN)4] and [ReO(OH)(CN)4]2- ions were clearly identified (Fig. 10). 

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