Ionic ternary

Sandri, G., Bonferoni, M. C., Chetoni, P., Rossi, S., Ferrari, F., Ronchi, C., et al. (2006), Ophthalmic delivery systems based on drug-polymer-polymer ionic ternary interaction In vitro and in vivo characterization, Eur. I. Pharm. Biopharm., 62(1), 59-69. 

Among cerium-containing nitride-type compounds, ternary nitrides in which Ce is tetravalent are formed with electropositive metals such as lithium or barium. These hygroscopic compounds are essentially ionic in character. In addition, oxynitrides containing cerium and barium are also known. However, surprisingly, no ionic ternary nitride (or quaternary oxynitride) involving other R elements has been described. 

The small size of lithium frequently confers special properties on its compounds and for this reason the element is sometimes termed anomalous . For example, it is miscible with Na only above 380° and is immiscible with molten K, Rb and Cs, whereas all other pairs of alkali metals are miscible with each other in all proportions. (The ternary alloy containing 12% Na, 47% K and 41% Cs has the lowest known mp, —78°C, of any metallic system.) Li shows many similarities to Mg. This so-called diagonal relationship stems from the similarity in ionic size of the two elements / (Li ) 76pm, / (Mg ) 72pm, compared with / (Na ) 102pm. Thus, as first noted by Arfvedson in establishing lithium as a new element, LiOH and LiiCOs are much less soluble than the corresponding... 

Table 3.6-2 The room-temperature electrochemical potential windows for binary and ternary chloroaluminate and related ionic liquids.

Despite the relatively short history of the chemistry of fluoride compounds, several thousands of binary and ternary fluoride compounds have been described, and their systematization is well developed [39 - 41]. Significant progress was achieved in the study of the crystal chemistry of fluoride compounds thanks to the ionic character of their chemical bonds and corresponding simplicity of their ciystal structure. The structure of these kinds of compounds is defined primarily by the geometry and the energy of mainly... 

Tell B, Wagner S, Kasper HM (1977) Ionic conduction in ternary chalcogenides. J Electrochem Soc 124 536-537... 

NMR measurements are very useful to understand the properties of the stabilizing reagents of metal nanoparticles. Author s group reported the structure of stabilization of non-ionic and cationic surfactants on platinum nanoparticles [22] and that of ternary amines on rhodium nanoparticles [23]. Such information is considerably important for applications of nanoparticles such as... 

This argument with respect to the ionic radii would predict a surface enrichment of Sn4+ (0.083 nm) for the ternary oxide, which is not observed. Hutchings et al. [50]... 

Ternary compounds are usually ionic, at least in part, except if they contain no metal atoms or ammonium ion. 

Table XIX contains stability constants for complexes of Ca2+ and of several other M2+ ions with a selection of phosphonate and nucleotide ligands (681,687-695). There is considerably more published information, especially on ATP (and, to a lesser extent, ADP and AMP) complexes at various pHs, ionic strengths, and temperatures (229,696,697), and on phosphonates (688) and bisphosphonates (688,698). The metal-ion binding properties of cytidine have been considered in detail in relation to stability constant determinations for its Ca2+ complex and complexes of seven other M2+ cations (232), and for ternary M21 -cytidine-amino acid and -oxalate complexes (699). Stability constant data for Ca2+ complexes of the nucleosides cytidine and uridine, the nucleoside bases adenine, cytosine, uracil, and thymine, and the 5 -monophosphates of adenosine, cytidine, thymidine, and uridine, have been listed along with values for analogous complexes of a wide range of other metal ions (700). Unfortunately comparisons are sometimes precluded by significant differences in experimental conditions.

An antisite defect is an atom on an inappropriate site in a crystal, that is, a site normally occupied by a different chemical species. In a compound of formula AB the antisite defects that can occur are an A atom on a site normally occupied by a B atom, or a B atom on a site normally occupied by an A atom. Antisite defects are not very important in binary ionic compounds, as the misplacement of an ion is energetically costly, and so unfavorable. In ternary ionic compounds, however, such as spinels, AB204, the transfer of A ions to B sites and vice versa, is not... 

A ternary reciprocal system is a system containing four components, but where these components are related through a reciprocal reaction. One example is the system LiCl-LiF-KCl-KF. Solid LiCl, LiF, KC1 and KF are highly ionic materials and take the rock salt crystal structure, in which the cations and anions are located on separate sub-lattices. It is therefore convenient to introduce ionic fractions (Xj) for each sub-lattice as discussed briefly in Section 3.1. The ionic fractions of the anions and cations are not independent since electron neutrality must be fulfilled ... 

Both the ternary systems are simple eutectic ones and the composition of the system is represented by the ionic fraction of one of the cations and one of the anions. In Figure 4.21 the ionic fraction of Li+ is varied along the X-axis, while the ionic fraction of F is varied along the 7-axis. 

Figure 7.15 (a) Enthalpy of formation of ternary oxides and nitrides from their binary constituent compounds as a function of the ratio of ionic potential [16]. Reprinted with permission from [16] Copyright (1997) American Chemical Society, (b) Gibbs energy of the oxide-sulfide equilibrium for group 1 and 2 metals at 1773 K as a function of the optical basicity of the metal. 

A typical example of energy minimization using interatomic potentials is a study [2] of the ternary fluorides AMF3 (A = Li+-Cs+, M = Mg2+-Ba2+). Not all these compounds have been reported experimentally. The computational study was based on structures adopted by AMO3 oxides, since the oxide and fluoride ions have similar ionic radii. The possible structures, shown in Figure 11.6, fall into two classes ... 

This problem was resolved by Nakae et al. [7] using non-polar octadecylsilica as the stationary phase and a solution of 0.1 M of sodium perchlorate in methanol/water (80 20) as the mobile phase. The ternary system (water-alcohol-salt), previously used by Fudano and Konishi [8] as an eluent for the separation of ionic surfactants at higher concentrations, induced the so-called salting out effect . The addition of the organic solvent to the water modified the polarity of the eluent and produced a good separation within a short period of time [9]. It also has the function of dissociating the surfactant micelles in individual molecules that are dissolved in the eluent [8], The presence of the salt (NaC104) in the mobile phase has a considerable influence on... 

About the same time Beutier and Renon (11) also proposed a similar model for the representation of the equilibria in aqueous solutions of weak electrolytes. The vapor was assumed to be an ideal gas and < >a was set equal to unity. Pitzer s method was used for the estimation of the activity coefficients, but, in contrast to Edwards et al. (j)), two ternary parameters in the activity coefficient expression were employed. These were obtained from data on the two-solute systems It was found that the equilibria in the systems NH3+ H2S+H20, NH3+C02+H20 and NH3+S02+H20 could be represented very well up to high concentrations of the ionic species. However, the model was unreliable at high concentrations of undissociated ammonia. Edwards et al. (1 2) have recently proposed a new expression for the representation of the activity coefficients in the NH3+H20 system, over the complete concentration range from pure water to pure NH3. it appears that this area will assume increasing importance and that one must be able to represent activity coefficients in the region of high concentrations of molecular species as well as in dilute solutions. Cruz and Renon (13) have proposed an expression which combines the equations for electrolytes with the non-random two-liquid (NRTL) model for non-electrolytes in order to represent the complete composition range. In a later publication, Cruz and Renon (J4J, this model was applied to the acetic acid-water system. 

---