Optimal acidity of complexes by solution of polynomials and by iteration.

The methods for optimal acidity of complexes M(x)L(y)(OH)(m)H(n) based on direct iteration or solution of polynomials are described and discussed. Then, by a direct straightforward method of computation (that does not require any iteration) the complexes M(x)L(OH)(m)H(n) and ML(y)(OH)(m)H(n) are treated (where 1 x 3 and 1 y 3). Finally, the conditions leading to formation of polynuclear complexes are shown and discussed. The importance of study of polynuclear complexes for solving of biochemical problems is pointed out. Practical examples are given for each method.

X-ray fluorescence spectrometry of copper intermediates.

Iron, magnetite, copper, copper(II) oxide, calcium carbonate, sulphur, silicon dioxide and aluminium oxide as components of copper intermediates (concentrates, slags, mattes, calcines and fluxes) in powdered (300-400 mesh) binary mixtures obey the Lachance-Traill equation, so the coefficients alpha(AX) of interelement effects can easily be determined experimentally. They show a reasonable agreement with the theoretical values calculated from mass absorption coefficients. This fact can be the basis of a convenient routine method for the determination of intermediates. Since the intermediates exhibit differences in the distribution of their atoms (microcosmic inhomogeneity) a correction factor k(dist) has to be used. Its value for the main components (concentrations > 5%) is in the range 0.92-1.24 The highest relative average deviation of the results from those of the classical "wet" methods is 2.7% for the major and 30% for the minor components.

Limits of the molar-ratio method.

The limiting factors (one constant molar-ratio of metal to ligand, constant excess of masking reagent and buffer, and high enough effective stability) of the molar ratio method are discussed. The lowest values of the effective stability constant for the true metal/ligand ratio to be determined for the complex and for a metal determination to be relatively independent of ligand concentration are calculated.

Stability constants of some metal dithizonates.

The overall stability constants of electroneutral dithizonates of bismuth, cadmium, cobalt(II), copper(II), iron(II), lead(II), manganese(II), mercury(II), nickel, palladium(II), silver, tin(II) and zinc were determined by means of stoichiometric dilution in aqueous solution stabilized by hydroxylamine hydrochloride, at pH 5.50-10.02. Stability constants of complexes ML of bivalent metals were determined under similar conditions but with an excess of metal.

Stabilities of some cyclopentadienide metal complexes.

The composition and stabilities of hydrogen, mangaoese(II), iron(II), cobalt(II), nickel(II) and palladium(II) complexes with cyclopentadienide were investigated spectrophotometrically in aqueous and dimethylformamide solutions. Corresponding effective and overall stability constants were determined.