Various cation ratios

Table II. Product Phases Observed for Various Cation Ratios...

Formation constants K for complexes of dicyclohexyl-18-crown-6 ether with various cations. Note that, although the radii of Ca ", Na" and Hg + are very similar, the ratio of the formation constants is 1 6.3 225. Again, K" and Ba " have similar radii but the ratio of K is 1 35 in the reverse direction (note log scale). 

Approximate selectivity coefficients for the exchange of various cations for lithium ions on a sulphonated polystyrene, a typically strong acid resin, are given in Table 18.1. The values are relative to Li = 1.0. The selectivity coefficient between two ions is the ratio of their selectivities relative to lithium. Hence, for a sodium-hydrogen exchange ... 

Table 3.1 Range of Radius Ratio Values for Various Cationic Coordination Numbers... 

We focus attention on the fact that the crystal radii (CRs) for the various cations listed in table 1.11 are simply equivalent to the effective ionic radii (IRs) augmented by 0.14 A. Wittaker and Muntus (1970) observed that the CR radii of Shannon and Prewitt (1969) conform better than IR radii to the radius ratio principle and proposed a tabulation with intermediate values, consistent with the above principle (defined by the authors as ionic radii for geochemistry ), as particularly useful for sihcates. It was not considered necessary to reproduce the... 

Table 1.5. Radius ratios for various cation coordination geometries in ionic compounds...

Fig. 6.3. Ideal (average observed) coordination number versus predicted coordination number for various cations. The predicted coordination numbers are calculated using the ratios of the Pauling (1960) six-coordinate radii by interpolating coordination numbers between the values given in Table 6.1. Most cations are represented by points, selected cations are shown by their chemical symbol and, where necessary, oxidation state.

Values of the radius ratio for various cations relative to oxygen are given in Table 13-19, together with the predicted ligancies, from Table... 

FIGURE 7.15 Plot of d(-U(r))/d( NO, orRlol) versus (a) the charge-to-size ratio or (b) the enthalpy of hydration for the extraction of the nitrates of various cations. (From R. Chiarizia, M. P. Jensen, P. G. Rickest, Z. Kolarik, M. Borowski, and P. Thiyagerrajan, Langmuir, 20 10798-10808, 2004. With permission.)... 

The subfragment 1 of myosin was investigated with the diastereomers of ATPClS as well as ATPfiS in the presence of various cations, particularly Mg2+, Cd3+, NH4+ and Tl+ (18 ). The Sp/R activity ratios obtained with the isomers of ATPClS were largely independent of the cation. The simplest explanation for this result is that the cations are not coordinated to the ci-phosphate group. Additional support for this contention comes from experiments em-... 

The product ratio in electrochemical reduction of benzalacetone is significantly altered by surfactants and various cations, which cause micellar and/or ion-pairing effects. Using these additives, it is possible to control the partitioning of the initially formed radical anion between the two main reaction pathways either dimerization or further reduction to the saturated ketone.Additionally, micellar surfactants allow the use of aqueous media without cosolvents. 

A theoretical treatment of metal halide extractions, encompassing various cationic, anionic, and polymeric species, has been presented by Diamond, who was particularly interested in molybdenum(VI) halides. Section 23-5 examines in more detail the questions of distribution ratios and chemical equilibria in the aqueous and organic phases. 

The microporous alumino-silicate zeolites (Types A, X, and mordenite are frequently used) provide a variety of pore openings (3-10 A), cavity and channel sizes, and framework Si/Al ratios. They are also available in various cationic exchanged forms (Na, K, Li, Ag, Ca, Ba, Mg), which govern their pore openings and cationic adsorption site polarities. They are highly hydrophilic materials and must be dehydrated before use. The amorphous adsorbents contain an intricate network of micropores and mesopores of various shapes and sizes. The pore size distribution may vary over a wide range. The activated carbons and the polymeric sorbents are relatively hydrophobic in nature. The silica and alumina gels are more hydrophilic (less than zeolites) and they must also be dehydrated before use. 

Noda et al. [ 168] reported the details of Bronsted acid-based ionic liquids consisting of a monoprotonic acid and an organic base, in particular solid bis(trifluorometha-nesulfonyl)amide (HTFSI) and solid imidazole (Im) mixed at various molar ratios to form liquid fractions. Studies of the conductivity, H NMR chemical shift, selfdiffusion coefficient, and electrochemical polarization results indicated that, for the Im excess compositions, the proton conductivity increased with an increasing Im molar fraction, with rapid proton-exchange reactions taking place between the protonated Im cation and Im. Proton conduction was found to occur via a combination of Grotthuss- and vehicle-type mechanisms. Recently, Nakamoto [169] reported the... 

Silicon—Cation Ratios in Solids and Stream Water. During low-flow periods of the Mattole river, the ratio of silicon (equivalents/liter) to alkalis plus alkaline earths (equivalents/liter) in solution is approximately 0.15-0.2, and following high flows it is in the range 0.8-0.9. These ratios can be compared with those in various common rock-forming minerals, as listed in Table IV. 

A series of zincosilicates MFI was synthesized from the mixtures of even Zn/Si ratio and various silicon sources. The properties of the resulting samples differed considerably regarding their zinc content, the crystallite morphology and size and catalytic activity. The samples modified with various cations (Ca, Cu, Zn, Al, H) showed some activity for 2-propanol dehydration (no acetone was detected). The samples modified with Al cations showed the highest activity. It is likely that part of Al could attain the framework positions or facilitate a generation of separated acidic OH groups. The lower activity of the H-forms could result from the presence of hydrogen bonds between adjacent hydroxyls. 

Table 4 gives the permeability ratios for various cations in the potassium channel of the node of Ranvier [23]. These values should be compared with those in Table 3... 

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