Crystal chemistry and stability of regular non-dense packings of spheres. Layers on the square net and structures on the primitive cubic lattice

摘要

In the context of the experimental and theoretical studies of the properties of substances in the state of uniform expansion, it was of interest to analyze possible structures with decreased density, which are stable at negative pressures. This paper reports on our crystal structure analysis of two- and three-dimensional structures with sublattices of vacancies constructed from identical atoms A on the square net and on the primitive cubic lattice. To compare the thermodynamic stabilities of these structures at 0 K we used the elementary potential of interatomic interactions whose parameters are the AA contact energy and the atomic radius. At any pressure within the admissible range of pressures, there exists a structure with a sublattice of vacancy clusters, which is more stable than the ideal flaw-free structure.