Determination of chemical composition of solid inorganic substances and materials using the principles of stoichiography and voltammetry

Abstract

The state of the art in determination of the phase composition of complex inorganic solids by chemical and electrochemical methods is discussed. The theoretical and practical essentials of stoichiography and the new stoichiographic method of differential dissolution (DD) are reported. The unique feature of this method is that reference samples of the analyzed solid phases are not necessary. The development of this stoichiographic method was strongly affected by voltammetry. The application of the DD method for determining the chemical composition of various substances and materials is presented. The complementary use of voltammetry and DD for the detection, identification, and quantitative determination of inhomogeneity of the chemical composition of hightemperature superconductors was shown to be efficient.

Experiments and Consideration about Surface Nonstoichiometry of Few-Layer MoS2 Prepared by Chemical Vapor Deposition

“…In general, the DD method might characterize the complex samples, providing information on number, content and composition of phases, going from the surface through the entire bulk of the sample. There are numerous examples of the DD application for precise examination of various high-tech materials in the form of crystals, thin films, and nanoscale powders. , …”

“…Here a unique ability of a new stoichiographic method of differential dissolution (DD) to separate complex mixture into individual phases and to identify them according to their stoichiometric formulas was used. Separation takes place for dissolution in the specially induced dynamic regime with progressively increasing concentration of solvent, and it is an effective method realizing functions of both bulk and local analysis simultaneously providing chemical information due to identification of compounds by their primary attribute, that is, the elemental stoichiometry. , XPS with different excitation energies allowed nondestructive determination of the altered layer composition, its extent to a depth, and finding of number and origin of nearest-neighboring atoms of Mo. IR spectroscopy being coupled to thermal gravimetric analysis may provide the quantitative characterization of absorbates.…”

Origin of the solid solution in the LiInSe 2 –In 2 Se 3 system

“…Nonlinear regions of the stoichiograms, short or long, reflect fine features of the test materials: phase state including microphases and chemical inhomogeneity in the form of surface and interface compositions. Special approaches and experimental procedures are developed to detect even small fluctuations of stoichiograms and interpret them correctly [11][12][13]. A detailed description of the experimental procedure of differential dissolution analysis to be applied to analysis of the LiBC 2 crystals is reported in [11,14,15].…”

“…It is a simple, rapid and effective technique and there are many examples of its application as a probe to monitor the evolution of chemical inhomogeneity on the sub-μm scale in different materials [11][12][13]. Analyzing with a high spatial resolution the compositional variability of the LiInSe 2 crystals, we could control precisely the level of their chemical inhomogeneity and elucidate the main mechanism of its occurrence.…”

Analytical Chemistry in Russia

“…The list of other achievements includes new versions and the first monograph on kinetic methods of analysis (K. B. Yatsimirskii) . A new approach in phase analysis called stechiography has been elaborated by V. V. Malakhov in Novosibirsk. , N. A. Tananaev developed, simultaneously with F. Feigl in Austria, the spot test method in the 1920s. Many analytical reagents were proposed in 1940–1980s, mostly for UV–vis spectrophotometry.…”