Oxygen ions/molecules

Electrical Conduction by Proton Jumps. As mentioned in Sec. 24, a hydroxyl ion may be regarded as a doubly charged oxygen ion 0 , containing a proton inside the electronic cloud of the ion, which has the same number of electrons as a fluoride ion. The radius of the hydroxyl ion cannot be very different from that of the fluoride ion. But it will be seen from Table 2 that the mobility of the hydroxyl ion is about four times as great. This arises from the fact that a large part of the mobility is undoubtedly due to proton transfers.1 Consider a water molecule in contact with a hydroxyl ion. If a proton jumps from the molecule to the ion,... 

Figure 10. The structures of (a) LinhV2, v04 s H20 and (b) Li06V2 i504,s. Hatched regions represent V05 square pyramids. The circles in (a) show the positions of the oxygen ions from the water molecules (adapted from Refs. [91,92J).

Positive Ion-Molecule Reactions. Some of the important ions identified in hydrocarbon/air or oxygen combustion are presented in Table II. With the exception of CHO+ and possibly C3H3+, all the ions are produced in ion-molecule reactions. 

Cations at the surface possess Lewis acidity, i.e. they behave as electron acceptors. The oxygen ions behave as proton acceptors and are thus Bronsted bases. This has consequences for adsorption, as we will see. According to Bronsted s concept of basicity, species capable of accepting a proton are called a base, while a Bronsted acid is a proton donor. In Lewis concept, every species that can accept an electron is an acid, while electron donors, such as molecules possessing electron lone pairs, are bases. Hence a Lewis base is in practice equivalent to a Bronsted base. However, the concepts of acidity are markedly different. 

Fig. 3. Oxygen transport in solids. 02 is dissociated and ionized at the reduction interface to give O2 ions, which are transferred across the solid to the oxidation interface, at which they lose the electrons to return back to 02 molecules that are released to the stream, (a) In the solid electrolyte cell based on a classical solid electrolyte, the ionic oxygen transport requires electrodes and external circuitry to transfer the electrons from the oxidation interface to the reduction interface (b) in the mixed conducting oxide membrane, the ionic oxygen transport does not require electrodes and external circuitry to transfer the electrons to the reduction interface from the oxidation interface, because the mixed conductor oxide provides high conductivities for both oxygen ions and electrons.

The lanthanide and actinide ions react with oxygen donor molecules. Recently, four selected lanthanide and actinide ions have been reacted with several sources of oxygen including 02. The formation of [MO]+ and [M02]+ ions were observed by the reactions of Ce+, Nd+, Th+, and U+ with 02. All reactions produced [MO]+ but [MOH]+ was a common minor product and [Th02]+ and [U02]+ ions were also obtained by the reaction of M+ with 02 (101). 

The M+ ions of groups 3 (IIIB), 4 (IVB), and 5 (VB) often react with oxygen containing molecules to form [MO]+. Bare metal ions (M+) are in a relatively rare oxidation state and so there are limited comparisons with condensed-phase... 

The non-bridging oxygen ion so produced is now capable of dissociating another water molecule ... 

As Fig. 2.4 illustrates, a cation can associate with a surface as an inner sphere, or outer-sphere complex depending on whether a chemical, i.e., a largely covalent bond, between the metal and the electron donating oxygen ions, is formed (as in an inner-sphere type solute complex) or if a cation of opposite charge approaches the surface groups within a critical distance as with solute ion pairs the cation and the base are separated by one (or more) water molecules. Furthermore, ions may be in the diffuse swarm of the double layer. 

Compound-specific isotope analysis (CSIA) by GC-IRMS became possible in 1978 due to work of Mathews and Hayes [634], based on earlier low-precision work of Sano et al. [635]. The key innovation was the development of a catalytic combustion furnace based on Pt with CuO as oxygen source, placed between the GC exit and the mass spectrometer. The high pressure of helium (99.999% purity or better) ensures that all gas flows are viscous. After being dried in special traps avoiding formation of HC02 (i. e., interferes with 13C02) by ion-molecule reactions in the ion source, the C02 is transmitted to a device that regulates pressure and flow and then into the ion source [604]. 

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