Complexes formation in aqueous solution

Seward, T.M. (1981) Metal complex formation in aqueous solutions at elevated temperatures and pressures. In Rickard, D.T. and Wickman, F.E. (eds.). Chemistry and Geochemistry of Solutions at High Temperatures and Pressures, Phys. Chem. Earth, 13 and 14, 113-132. 

Seward T. M. (1981). Metal complex formation in aqueous solutions at elevated temperatures and pressures. Phys. Chem. Earth, 13 113-132. 

Table 9. Log K Values for M +-macrobicyclic ligand complex formation in aqueous solution. ) (34)...

The equilibrium in equation (94) is generally defined as a mass-distribution ratio such as that shown above for cation-exchange resins (equation 93), and the position of the equilibrium is determined by the relative Concentration of the counter-ion ML/- and the co-ion X-. The nature of the quaternary amine has little effect on the equilibrium properties of the resin, and the chemistry of metal complex formation in aqueous solution is the dominant factor. 

By comparison with studies of complex formation in aqueous solution, the gaseous transport of coordination compounds in geochemical systems has received scant attention despite many pointers to the possibility, especially concerning volcanic emanations, arising from metallurgical processes. In Section 64.2 reference was made to a number of halides associated with fumarolic... 

The equilibrium constants for complex formation in aqueous solution are not high compared to those for Fe2+—Cu2+ because the Mn11 ion is the largest of these and it has no ligand field stabilization energy in its complexes (except in the few of low spin). 

Consider complex ion formation in the CdClj-KCl system, and let it be assumed for the moment that a CdCl complex ion is formed. If such complex ions were formed in an aqueous solution of CdClj and KCl, they would exist as little islands separated from other ions by large expanses of water. In fused salts, there are no oceans of solvent separating the ions. Thus, a Cd " ion would constantly be coming into contact on all sides with chloride ions, and yet one singles out three of these CP ions and says that they are part of (or belong to) a CdCIJ complex ion (Fig. 5.54). It appears that in the absence of the separateness possible in aqueous solutions, the concept of complex ions in molten salts is suspect As will be argued later, however, what is dubious turns out to be not the concept but the comparison of complex formation in fused salts with complex formation in aqueous solutions. 

AHR/AVS] Ahrland, S., Avsar, E., Kullberg, L., Thermodynamics of metal complex formation in aqueous solution. VI. Equilibrium and enthalpy measurements on the zinc and cadmium selenocyanate systems, Acta Chem. Scand, A 28, (1974), 855-865. Cited on pages 206, 266, 276, 277. 

A detailed discussion of the thermodynamics of complex formation in aqueous solution lies beyond the scope of this book, but we discuss briefly entropy changes that accompany the formation of coordination compounds in solution, and the so-called chelate ejfect. In Chapter 20, we look further at the thermodynamics of complex formation. 

It may be noted finally that 7Li (92.7%) gives nuclear magnetic resonance signals comparable to those given by so that complex formation in aqueous solutions can be studied in this way it was shown24 that nitrilo-triacetic acid, N(CH2COOH)3 (NTA), probably forms a complex ion, [Li(NTA)2]5, in solution. 

A rough order of reactivity of +2 metal ions follows from the rates of complex formation in aqueous solution, and is... 

F1A/SHE] Fialkov, Y. A., Sheka, Z. A., Complex formation in aqueous solutions of sulfuric acid and some metal sulfates, Russ. J. Inorg. Chem., 1, (1956), 120-125. Cited on pages 181, 284. 

The crystal structures of the three heavier thallium(I) halides have been established and lattice energies calculated the inert pair of T1+ is apparently insignificant in terms of the stability of the lattice. The enthalpy of hydration of the Tl ion was also derived. Gas phase (TlBr, Til) and matrix isolation studies (TlCl, TlBr, Til) have shown that TlX and TI2X2 species are important.Complex formation in aqueous solution decreases in the order Cl > Br > I, and as with the fluorides, the double salts show no evidence of anionic complex formation by Tl Finally, it is important to note that TII3 is formulated as Tr(lT) from X-ray studies.Thermal decomposition yields TI3I4, whose structure has not been reported. 

Amodiaquine hydrochloride is determined colorimetrically by complex formation, in aqueous solution, with bromophenol blue, bromocresol green, bromocresol purple, and methyl orange, respectively. The complex with bromophenol blue has the highest molar absorptivity. Recoveries are more than 98.6% for all complexes, and the absorbance is linear with concentration in the range 1-11 Ag/nd. The absorption maxima for the complexes occur at 420 nm except for the bromocresol purple complex which exhibits maximum at 415 nm. The various complexes are extracted with chloroform and absorbance is measured at the respective maxima for quantitative determination (28). 

In 1961, Eastman Kodak found that diesters and tetraesters, such as (149) and (150), increased the sensitivity of silver halide emulsions already sensitized with gold compounds <61BP588242>. Hengel investigated the correlation between complex formation in aqueous solutions and photographic activity <83MI 932-02). 

Thermodynamic characteristics of Ca-EDTA complex formation in aqueous solution have been derived at 288, 298, and 308 K and at ionic strengths of 0.3, 0.5, and 1.0 (KNOj). Conductivity and i.r. data suggest that CaH2EDTA is an acid salt of EDTA, and that the concentration of the ionic complex (if it exists) is negligible." ... 

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