Crystallographic Analysis of Symmetry-Stability Relations in Atomic Structures

Widely known and some other structural types as well as mechanisms of structural transformations are considered in the framework of the idea that stability of crystal structures is caused by translational and point spatial symmetries, which reduce the degree of freedom and, therefore, the energy of material particles (atoms, chemically stable atomic groups). The role of highly symmetric spatial “stencils” of atomic arrangement in the solution of the composition—structure problem is shown. Criteria of relative stability of crystal structures are proposed.