Icosahedral nanoclusters-precursors and self-assembly of crystal structures of the WAl12 (Im-3, cI26) family and sillenite Bi12 SiO20 (I23, cI66)

摘要: The self-assembly of crystal structures the family WAl12 (Im-3, cI26) and sillenite Bi12SiO20 (I23, cI66) has been simulated. methods combinatorial topological analysis (TOPOS program package) have used based on determination type cluster-precursor building basic 3D net structure in form a graph, nodes which correspond to position centers gravity clusters-precursors, edges characterize bonds between them. corresponds body-centered Fe (with BCC type). symmetric-topological code processes self-assembling from nanoclusters-precursors—primary chain → microlayer micronetwork—has completely reconstructed. chemical composition icosahedral nanoclusters-precursors 13 atoms for 33 compounds whole. is an icosahedron 12 Al with W atom center. occupies 2a unit cell highest crystallographically possible symmetry m-3. In structure, location 32 shell nanocluster Bergman cluster: vertices are occupied by Bi atoms, oxygen four also coupled Si located center cluster, above below 20 faces icosahedron. Nanoclusters occupy positions cell. can be obtained removal O system icosahedra conserved.