Display of cross-sections showing packing in inclusion compounds

A system of BASIC programs for a personal computer allowing the display of plane sections through crystal structures has been developed in order to analyse intermolecular contacts as well as the shape and size of intra- or intermolecular voids in the structure of inclusion compounds. The data consisting of lattice parameters, type of Bravais lattice, symmetry operations, and positional parameters of atoms in an asymmetric unit are stored in a data file, reusable and correctable. The structure is considered as an assembly of spherical atoms of given van der Waals radii. The section plane may be defined by either coordinates of three points or the crystallographic index. A series of sections parallel to the original one at a specified interval of distance may be calculated and displayed automatically, and memorized for further reviewing, modifying graphic features, etc. Hard copies may be prepared using a dot-matrix printer or plotting devices. The program may be applicable to any crystal structure with an arbitrary choice of atomic radii.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on Cyclodextrins, Lancaster, U.K., 20–25 July 1986.