STRUCTURAL STABILITY OF CONTAINER CRYSTALS FOR SOME ANTI-ZEOLITES

摘要

The crystallographic analysis of the structures of Yb-3(BO3(OH)(6))center dot 2H(2)O (I), Ba8Ni4[BP3O11(OH)(2)](4) (II), and Pb-4(O(OH)(2))SiO4 (III) shows that they are based on sublattices of heavy Yb, Ba, Pb cations with similar parameters and a significant fraction of vacant nodes, which provides the formation of bulk voids. The key role of these cations also manifests itself in the fact that they occupy special positions with fixed coordinates and a high local symmetry. The crystallization process is a coherent assembly of chemically stable cation groups formed in the precrystallization phase of a substance.