Towards a general description of hexagonal three-dimensional framework structures: the lateral connection of trigonal columns (LCTC) group

Hexagonal three-dimensional framework structures are constructed from trigonal columns. When two types of trigonal column are distinguished, all hexagonal 3D framework structures known to date can be classified in the lateral connection of trigonal columns (LCTC) group. Also, orthorhombic 3D nets can be constructed from trigonal columns and a number of such hypothetical nets related to the hexagonal 81(i) series of Smith & Dytrych [Nature (London) (1984), 309, 607-608] are enumerated. A systematic investigation of the several ways by which neighbouring trigonal columns can be linked and symmetry related gives rise to a large number of subgroups in the present LCTC group. A general designation for LCTC structures by means of a composite code is proposed.