Complexes overall formation constant

In Chapter 3 we described how an uncharged metal complex MA is formed from a metal ion central atom) through a stepwise reaction with the anion A (ligand) of a monobasic organic acid, HA, defining a stepwise formation constant k , and an overall formation constant (3 , where... 

The reaction between Craq002+ and N02 appears to be the only documented study of the interaction of a superoxometal complex with N02. The 0-0 bond in the product Craq00N02+ is weak and cleaves in the reverse process, the overall formation constant being... 

Table 5. Overall formation constants of Cu(II) complexes with various polymer ligands...

The [Ni(CN)4]2 anion is one of the most stable nickel(II) complexes and an overall formation constant as high as about 1030 has been determined.627,62 The structure of the complex is square planar with the nickel(II) bound to carbon atoms of cyanides and with linear Ni—C—N linkages (Table 37).629 630 The planar [Ni(CN)4]2 units are stacked in columns in the crystal lattice with Ni—Ni interlayer distances as short as 330 pm. C-bonded CN- is a strong field donor and the electronic spectrum of [Ni(CN)4]2 shows two weak d-d bands at 444 and 328 nm. 

Pi and // represent the overall formation constant for the different complexes of species A or B, respectively, initially present in solution ... 

All the ions can form string complexes, the overall formation constants for tetrahedral [ML4] species (e.g., [HgCl4]2-) with a selection of ligands, being shown in the table given ahead. There is an increasing tendency to soft class b behaviour in the order... 

In the case of Ag+, only two imidazolyl groups participate in complex formation, and the overall stability constant is log p2 = 8.00, about one order of magnitude larger than the overall formation constant of the Ag/imidazole complex (log p2 = 6.84). Complexes of Cu2 + with poly 4(5)-vinyl-imidazole, poly(N-vinyl-imidazole), and... 

The larger the value of the constant is, the more stable the complex (Table 12.11). The metal-ammine formation constants Ksl and Kst are known as stepwise formation constants. Stepwise formation constants1 could be used to estimate overall formation constants. For example,... 

Replacing the metal-ammine complexes in the denominator as a function of NH3, M2+, and overall formation constants, as demonstrated in Equation 12.24, gives... 

The existence of Tl cyanide complexes has been mentioned previously however, on the basis of the analogy with other Tl -pseudohalide redox reactions, and by analysis of the redox potentials, the existence of the T1(CN) "" complexes was not widely accepted for a time. However, a detailed investigation of this system using ° T1 and NMR spectroscopy has indicated that Tl indeed forms very stable cyanide complexes (the overall formation constants,... 

Table 1. Overall formation constants (log P) for the complexes and pK values for deprotonation processes in the systems copper(II) - A -D-gluconylamino acid (T = 298 K, I = 0.1 mol dm, NaC104)...

Uranium tetrafluoride is a key intermediate in the production of thermal reactor fuels. It may be prepared directly from uranyl solutions by reduction of the U to U and addition of HF to precipitate UF4. A number of processes have been developed to produce UF4 by this wet route, which may be used to produce UF4 at the ore processing site. These employ iron, S02/Cu or electrolysis for the reduction step, the latter being preferred since it introduces no contaminants into the solution. The reduction of u in various media has been studied to assess the effect of complexation on the reduction reaction. The standard potential for the reduction of U02 to in 1 M HCIO4 has been given as +0.32 V. " The overall formation constants of fluoride complexes in 1 M NaCl were found to be log 82= 13.12, logj83 = 17.46 and log/84 = 21.8. Although wet processes have been developed as a short cut to UF4, the most widely used process at present involves dry processing. 

As shown by the values of the formation constants found by solvent extraction (overall formation constants] and by spectrophotometry (inner sphere formation constants], it is safe to assume that azide complexes are mostly inner sphere. This is also supported by the values of the formation constant of Eu (III] calculated using the charge transfer band whose appearance must be attributed to close contact between azide and metal ion. 

Stepwise and Overall Formation Constants for Complex Ions... 

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