Differential Dissolution Stoichiographic Method in Investigation of the Chemical Composition of Functional Materials

— This paper presents examples that characterize various aspects of the possibility of determining the phase composition of solid multielement substances and materials containing nanostructured forms of their components by a differential dissolution stoichiographic method. The use of stoichiography makes it possible to detect and quantitatively determine both known and unknown crystalline and amorphous phases of constant and variable composition without standards of solid phases. The use of stoichiographic methods and ideas of nonequilibrium thermodynamics allows one to gain fundamentally new data on solid-state transformations of multielement, multiphase substances and materials.