Solvation stoichiometries

The second stage of modeling is the introduction of solvated ionic species into the model double layer. Coadsorption of HF and water yields adsorbed HgO ions the solvation stoichiometries of ions in the first monolayer and in subsequent layers are determined. The third stage of modeling is establishment of potential control in UHV. Hydrogen coadsorption is used to deflect the effective potential of the water monolayer below the potential of zero charge. The unique ways in which UHV models can contribute to an improved molecular-scale understanding of electrochemical interfaces are discussed. 

Srinivasan, T.G. Suresh, A. Prasanna, R. Jayanthi, N. Vasudeva Rao, P.R. Metal-solvate stoichiometry evaluation in extractions by solvating type neutral extractants -A novel approach, Solvent Extr. Ion Exch. 14 (1996) 443-458. 

The model related to eq. [9.99a] was evaluated,resulting in the supposition that the equilibrium of two forms of solvated proton HA and HB is important. Solvation stoichiometry was not considered. Both proton solvated forms are denoted as HA" and HB". ... 

Novel techniques for the creation of co-crystals and solvates such as neat and liquid assisted grinding have challenged the ability of crystal structure prediction to predict stoichiometry from first principles. Recent work has addressed the problem of predicting solvate stoichiometry of acetic acid (the solvent) with various molecules including carbamazepine (CBZ) and its 10,11-dihydro derivative (DHCBZ), urea and theobromine(see Figure 4.8). 

At present, intercalation compounds are used widely in various electrochemical devices (batteries, fuel cells, electrochromic devices, etc.). At the same time, many fundamental problems in this field do not yet have an explanation (e.g., the influence of ion solvation, the influence of defects in the host structure and/or in the host stoichiometry on the kinetic and thermodynamic properties of intercalation compounds). Optimization of the host stoichiometry of high-voltage intercalation compounds into oxide host materials is of prime importance for their practical application. Intercalation processes into organic polymer host materials are discussed in Chapter 26. 

If solvent is added to either of the solid eutectics represented by e or e in Fig. 25a or b, the undissolved solid retains this composition while the saturated solution maintains the composition E or E, respectively. Again, Gibbs phase rule [145,146] can provide further insight into these systems. If the solid enantiomers are solvated, the compositions of the equilibrium solids are displaced symmetrically along the DS or LS axes to an extent determined by the stoichiometry of the solvates. Similarly, if the racemic compound is solvated, the stoichiometry of the equilibrium solid is displaced from R along the line RS to an extent determined by the stoichiometry of the solvate. 

The stoichiometry illustrates how each formula unit generates a single solvated proton. By contrast, sulphuric acid, H2SO4, dissociates in solution according to... 

Equation (6.27) demonstrated how the concentration of the solvated protons equates to the concentration of a mono-protic acid from which it derived but, from Equation (6.28), the concentration of the solvated protons will be twice the concentration if the parent acid is di-protic. These different stoichiometries affect the pH, as demonstrated now by Worked Examples 6.6 and 6.7. 

The lanthanide halides form a wide range of solvates with a variety of organic solvents for a given halide and solvent, a range of stoichiometries may be exhibited. Some idea of the range of solvents involved is given by Table II (108,112,142-166), which gives references to numerous solvates. The collection of citations in this table is illustrative, not comprehensive. 

In the following general discussion n = 1 will be assumed for simplicity. Other stoichiometries will be considered in the text when relevant. All three species L, S and LS are solvated to various extents. 

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