Cation anion effect

With the exception of PRs used for direct application, thCTe normally is a negl ible difference in crop response between sources of the common P fertilizers, which indicates in itself that differences in wat solubility is not a major factor in determining P availability. A possible exception to this generalization is that N-P sources are sometimes more efficiently used in banded applications because of N-P interaction created by increased root proliferation in the fertilizer zone and anion/cation effects. The effect of placing ammonium sources with water-soluble P has been shown to be the most beneftdal. 

The anion-cation effects of the adsorbents are significant. For example, sulfates cause elution temperature to increase compared to chlorides. 

S ts can be used to precipitate proteins by salting out effects. The effectiveness of various salts is determined by the Hofmeister series, with anions being effective in the order citrate > PO4" > SO4" > CH3COO > Cl > NO3 , and cations according to NH4 > > Na ... 

If the cation has been unchanged, its ability to act as a hydrogen-bond donor has been unchanged, so why is an effect seen at all I propose that there is competition between the anion and the Reichardt s dye solute for the proton. Thus, the values of the ionic liquids are controlled by the ability of the liquid to act as a hydrogen bond donor (cation effect) moderated by its hydrogen bond acceptor ability (anion effect). This may be described in terms of two competing equilibria. The cation can hydrogen bond to the anion [Equation (3.5-2)] ... 

There is a wide variety of solid electrolytes and, depending on their composition, these anionic, cationic or mixed conducting materials exhibit substantial ionic conductivity at temperatures between 25 and 1000°C. Within this very broad temperature range, which covers practically all heterogeneous catalytic reactions, solid electrolytes can be used to induce the NEMCA effect and thus activate heterogeneous catalytic reactions. As will become apparent throughout this book they behave, under the influence of the applied potential, as active catalyst supports by becoming reversible in situ promoter donors or poison acceptors for the catalytically active metal surface. 

The study of the MEEP/PEO-(LiX)n and MEEP/PPO-(LiX)n complexes, (X= BF4, CIO4) by Li NMR spectroscopy, DSC and X-ray diffraction showed that they were multiphase with amorphous MEEP and crystalhne PEO phases. Strong cation-anion association effects were also observed [612]. 

The general subject of lactone polymerization has been reviewed (7, 19). Polymerization of e-caprolactone can be effected by at least four different mechanisms categorized as anionic, cationic, coordination, and radical. Each method has unique attributes, providing... 

To sum up, in addition to the electronic stabilization and solvation, classical steric congestion caused by either the cation or anion moieties effectively controls the ease of ionic dissociation of the carbon-carbon a bond in hydrocarbons. 

Licht S, Tenne R, Flaisher H, Manassen J (1986) Cation effects on the electrochemistry of anions in polysulfide photoelectrochemical cells. J Electrochem Soc 133 52-59... 

Okada et al. have presented a dynamic dissociation model, which is schematically shown in one dimension in Fig. 4. They assumed that the separating motion of a cation (or anion) of interest from the reference anion (cation), which is called the self-exchange velocity,is the electrically conducting process, which will be considered in Section III.7( ) in more detail. The Chemla effect can also be reproduced by the SEV. 

Surfactants. The use of surfactants is greatly restricted in formulating ophthalmic solutions. The order of surfactant toxicity is anionic > cationic >> nonionic. Several nonionic surfactants are used in relatively low concentrations to aid in dispersing steroids in suspensions and to achieve or to improve solution clarity. Those principally used are the sorbitan ether esters of oleic acid (Polysorbate or Tween 20 and 80), polymers of oxyethylated octyl phenol (Tyloxapol), and polyoxyl 40 stearate. The lowest concentration possible is used to perform the desired function. Their effect on preservative efficacy and their possible binding by macromolecules must be taken into account, as well as their effect on ocular irritation. The use of surfactants as cosolvents for an ophthalmic solution of chloramphenicol has been described [271]. This com-... 

Some of the reports are as follows. Mizukoshi et al. [31] reported ultrasound assisted reduction processes of Pt(IV) ions in the presence of anionic, cationic and non-ionic surfactant. They found that radicals formed from the reaction of the surfactants with primary radicals sonolysis of water and direct thermal decomposition of surfactants during collapsing of cavities contribute to reduction of metal ions. Fujimoto et al. [32] reported metal and alloy nanoparticles of Au, Pd and ft, and Mn02 prepared by reduction method in presence of surfactant and sonication environment. They found that surfactant shows stabilization of metal particles and has impact on narrow particle size distribution during sonication process. Abbas et al. [33] carried out the effects of different operational parameters in sodium chloride sonocrystallisation, namely temperature, ultrasonic power and concentration sodium. They found that the sonocrystallization is effective method for preparation of small NaCl crystals for pharmaceutical aerosol preparation. The crystal growth then occurs in supersaturated solution. Mersmann et al. (2001) [21] and Guo et al. [34] reported that the relative supersaturation in reactive crystallization is decisive for the crystal size and depends on the following factors. 

The influence of pressure has also been used to tune the ST properties of these ID chain compounds. Application of hydrostatic pressure ( 6 kbar) on [Fe(hyptrz)3] (4-chlorophenylsulfonate)2 H20 (hyptrz=4-(3 -hydroxypro-pyl)-l,2,4-triazole) provokes a parallel shift of the ST curves upwards to room temperature (Fig. 5) [41]. The steepness of the ST curves along with the hysteresis width remain practically constant. This lends support to the assertion that cooperative interactions are confined within the Fe(II) triazole chain. Thus a change in external pressure has an effect on the SCO behaviour comparable to a change in internal electrostatic pressure due to anion-cation interactions (e.g. changing the counter-anion). Both lead to considerable shifts in transition temperatures without significant influence on the hysteresis width. Several theoretical models have been developed to predict such SCO behaviour of ID chain compounds under pressure [50-52]. Figure 5 (bottom) also shows the pressure dependence of the LS fraction, yLS, of... 

The stability of crown-ether complexes depends on several factors these include cavity size of the ligand, cation diameter, spatial distribution of ring binding sites, the character of the hetero-atoms, the presence of additional binding sites and the type of solvent used. In apolar solutions it also depends on the nature of the anion. The effects of these parameters will be illustrated in the next sections. 

It has become popular to attribute to crown ethers an anion activation effect which term suggests that their presence causes an increase in reaction rate. Although this is certainly true in many cases, it does not hold for reactions in which the ion pair is much more reactive than the free anion as a result of a cation-assisted reaction pathway. In addition to anion activation , crown ethers also exhibit cation deactivation . 

The phase behavior of anionic-cationic surfactant mixture/alcohol/oil/ water systems exhibit a similar effect. First of all, it should be mentioned that because of the low solubility of the catanionic compound, it tends to precipitate in absence of co-surfactant, such as a short alcohol. When a small amount of cationic surfactant is added to a SOW system containing an anionic surfactant and alcohol (A), three-phase behavior is exhibited at the proper formulation, and the effect of the added cationic surfactant may be deduced from the variation of the optimum salinity (S ) for three-phase behavior as in Figs. 5-6 plots. Figure 16 (left) shows that when some cationic surfactant is added to a SOWA system containing mostly an anionic surfactant, the value of In S decreases strongly, which is an indication of a reduction in hydrophilicity of the surfactant mixture. The same happens when a small amount of anionic surfactant is added to a SOWA system containing mostly a cationic surfactant. As seen in Fig. 16 (left), the values of In S at which the parent anionic and cationic surfactant systems exhibit three-phase behavior are quite high, which means that both base surfactants, e.g., dodecyl sulfate... 

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