Combinatorial-topological modeling of the cluster self-assembly of crystal structures of zeolites of the GME, AFX, AFT, and ISC-2 family

摘要

Combinatorial-topological 3D modeling of periodic packages from T-12 polyhedral clusters has been carried out (t-hpr tiles in the form of hexagonal prisms), most frequent in the crystal zeolite structures. A basic 2D microlayer L is obtained by decoding a single-node 2D grid of the 6.6.6 type of graphite and it contains cyclic hexamers (T-12)(6). The hexamer is located in a triple hexagonal cell with a (hex) = 13.90 ; the height of the layer is about 10 . In theory, the formation of an unlimited number of structures of polytypes with cell parameters of c (hex) = N x 10 is possible due to the different variants of the complementary communication of the L layers with each other (both with and without a shift). For the three obtained models of skeletons, an analogy is found with the following known zeolites: GME (mineral Gmelinite, P6(3)/mmc, c (hex) = 10 ), which is classified as a single layer 1H-polytype from the translation-related layers L, AFX-2H-polytype (P6(3)/mmc, c (hex) = 20) and AFT-3H-polytype (P6(3)/mmc, c (hex) = 30 ). A new 3H-polytype ISC-2 is found with parameters a = 13.90 , c = 30.00 , V = 5019.7 (3), and P-6m2 (187). Using a TOPOS program pack, a set of tiles T (n) is determined characterizing all polyhedral zeolite cavities: t-hpr-12T, t-gme-24T, t-aft-48T, and t-isc-72T (a new type of tile). It is assumed that the synthesis of skeletonized compound Al36P36O144 can be carried out by selecting the corresponding organic structure directing agents (OSDA molecules) in order to stabilize local areas corresponding to the cavities of the largest size (t-isc-72T size).