Stoichiography: New Ways Determining Chemical Composition and Real Structure of Materials

Abstract

The principles of stoichiography and novel reference-free methods of molecular and phase analysis for complex unknown mixtures are considered. The stoichiography can be inferred from stoichiometry of mass transfer of unsteady homo- and heterophase processes and joins both operations: separation of mixture by means of chromatography, electromigration, dissolution or others and determination of stoichiometry of a substance flow with time. The stoichiography allows a chemical compound to be determined by its primary property, namely, by stoichiometry of elemental composition. Stoichiograms provided a basis for such type of information. They are time variances of molar ratio for mass transfer rates of chemical elements from multielement substances. Invariancy to concentration and temperature of solvents, hydrodynamic regime is a fundamental property of the stoichiograms in the case of individual compounds. Therefore the stoichiograms are kept constant and are equal to formula stoichiometric coefficients of the individual compound. Theory and methodology of new stoichographic methods, differential dissolution and ion-chromato-stoichiography are presented. New equipment, stoichiograph, and a new procedure of differential dissolution, stoichiographic titration, are discussed here in details. Applications of differential dissolution to analyze multielement and polyphase crystalline and amorphous samples are given. ***The author devotes this paper to memory of his teacher, Professor O. A. Songina, an outstanding scientist, who began to develop fundamental ideas concerning chemical and electrochemical methods of the phase analysis. The essence of this paper was reported on International Conference of Analytical Chemistry, which was organized on the occasion of the 100th Birthday of Professor O. A. Songina on May 22-25th, 2001, in Almaty, Kazakhstan.